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en/2033.html.txt

@@ -0,0 +1,1277 @@
+
+
+In physics, a force is any interaction that, when unopposed, will change the motion of an object. A force can cause an object with mass to change its velocity (which includes to begin moving from a state of rest), i.e., to accelerate. Force can also be described intuitively as a push or a pull. A force has both magnitude and direction, making it a vector quantity.  It is measured in the SI unit of newtons and represented by the symbol F.
+
+The original form of Newton's second law states that the net force acting upon an object is equal to the rate at which its momentum changes with time. If the mass of the object is constant, this law implies that the acceleration of an object is directly proportional to the net force acting on the object, is in the direction of the net force, and is inversely proportional to the mass of the object.
+
+Concepts related to force include: thrust, which increases the velocity of an object; drag, which decreases the velocity of an object; and torque, which produces changes in rotational speed of an object. In an extended body, each part usually applies forces on the adjacent parts; the distribution of such forces through the body is the internal mechanical stress. Such internal mechanical stresses cause no acceleration of that body as the forces balance one another. Pressure, the distribution of many small forces applied over an area of a body, is a simple type of stress that if unbalanced can cause the body to accelerate. Stress usually causes deformation of solid materials, or flow in fluids.
+
+Philosophers in antiquity used the concept of force in the study of stationary and moving objects and simple machines, but thinkers such as Aristotle and Archimedes retained fundamental errors in understanding force. In part this was due to an incomplete understanding of the sometimes non-obvious force of friction, and a consequently inadequate view of the nature of natural motion.[1] A fundamental error was the belief that a force is required to maintain motion, even at a constant velocity. Most of the previous misunderstandings about motion and force were eventually corrected by Galileo Galilei and Sir Isaac Newton. With his mathematical insight, Sir Isaac Newton formulated laws of motion that were not improved for nearly three hundred years.[2] By the early 20th century, Einstein developed a theory of relativity that correctly predicted the action of forces on objects with increasing momenta near the speed of light, and also provided insight into the forces produced by gravitation and inertia.
+
+With modern insights into quantum mechanics and technology that can accelerate particles close to the speed of light, particle physics has devised a Standard Model to describe forces between particles smaller than atoms. The Standard Model predicts that exchanged particles called gauge bosons are the fundamental means by which forces are emitted and absorbed. Only four main interactions are known: in order of decreasing strength, they are: strong, electromagnetic, weak, and gravitational.[3]:2–10[4]:79 High-energy particle physics observations made during the 1970s and 1980s confirmed that the weak and electromagnetic forces are expressions of a more fundamental electroweak interaction.[5]
+
+Since antiquity the concept of force has been recognized as integral to the functioning of each of the simple machines. The mechanical advantage given by a simple machine allowed for less force to be used in exchange for that force acting over a greater distance for the same amount of work. Analysis of the characteristics of forces ultimately culminated in the work of Archimedes who was especially famous for formulating a treatment of buoyant forces inherent in fluids.[1]
+
+Aristotle provided a philosophical discussion of the concept of a force as an integral part of Aristotelian cosmology. In Aristotle's view, the terrestrial sphere contained four elements that come to rest at different "natural places" therein. Aristotle believed that motionless objects on Earth, those composed mostly of the elements earth and water, to be in their natural place on the ground and that they will stay that way if left alone. He distinguished between the innate tendency of objects to find their "natural place" (e.g., for heavy bodies to fall), which led to "natural motion", and unnatural or forced motion, which required continued application of a force.[6] This theory, based on the everyday experience of how objects move, such as the constant application of a force needed to keep a cart moving, had conceptual trouble accounting for the behavior of projectiles, such as the flight of arrows. The place where the archer moves the projectile was at the start of the flight, and while the projectile sailed through the air, no discernible efficient cause acts on it. Aristotle was aware of this problem and proposed that the air displaced through the projectile's path carries the projectile to its target. This explanation demands a continuum like air for change of place in general.[7]
+
+Aristotelian physics began facing criticism in medieval science, first by John Philoponus in the 6th century.
+
+The shortcomings of Aristotelian physics would not be fully corrected until the 17th century work of Galileo Galilei, who was influenced by the late medieval idea that objects in forced motion carried an innate force of impetus. Galileo constructed an experiment in which stones and cannonballs were both rolled down an incline to disprove the Aristotelian theory of motion. He showed that the bodies were accelerated by gravity to an extent that was independent of their mass and argued that objects retain their velocity unless acted on by a force, for example friction.[8]
+
+Sir Isaac Newton described the motion of all objects using the concepts of inertia and force, and in doing so he found they obey certain conservation laws. In 1687, Newton published his thesis Philosophiæ Naturalis Principia Mathematica.[2][9] In this work Newton set out three laws of motion that to this day are the way forces are described in physics.[9]
+
+Newton's First Law of Motion states that objects continue to move in a state of constant velocity unless acted upon by an external net force (resultant force).[9] This law is an extension of Galileo's insight that constant velocity was associated with a lack of net force (see a more detailed description of this below). Newton proposed that every object with mass has an innate inertia that functions as the fundamental equilibrium "natural state" in place of the Aristotelian idea of the "natural state of rest". That is, Newton's empirical First Law contradicts the intuitive Aristotelian belief that a net force is required to keep an object moving with constant velocity. By making rest physically indistinguishable from non-zero constant velocity, Newton's First Law directly connects inertia with the concept of relative velocities. Specifically, in systems where objects are moving with different velocities, it is impossible to determine which object is "in motion" and which object is "at rest". The laws of physics are the same in every inertial frame of reference, that is, in all frames related by a Galilean transformation.
+
+For instance, while traveling in a moving vehicle at a constant velocity, the laws of physics do not change as a result of its motion. If a person riding within the vehicle throws a ball straight up, that person will observe it rise vertically and fall vertically and not have to apply a force in the direction the vehicle is moving. Another person, observing the moving vehicle pass by, would observe the ball follow a curving parabolic path in the same direction as the motion of the vehicle. It is the inertia of the ball associated with its constant velocity in the direction of the vehicle's motion that ensures the ball continues to move forward even as it is thrown up and falls back down. From the perspective of the person in the car, the vehicle and everything inside of it is at rest: It is the outside world that is moving with a constant speed in the opposite direction of the vehicle. Since there is no experiment that can distinguish whether it is the vehicle that is at rest or the outside world that is at rest, the two situations are considered to be physically indistinguishable. Inertia therefore applies equally well to constant velocity motion as it does to rest.
+
+A modern statement of Newton's Second Law is a vector equation:[Note 1]
+
+where 
+
+
+
+
+
+
+p
+→
+
+
+
+
+
+{\displaystyle {\vec {p}}}
+
+ is the momentum of the system, and 
+
+
+
+
+
+
+F
+→
+
+
+
+
+
+{\displaystyle {\vec {F}}}
+
+ is the net (vector sum) force. If a body is in equilibrium, there is zero net force by definition (balanced forces may be present nevertheless). In contrast, the second law states that if there is an unbalanced force acting on an object it will result in the object's momentum changing over time.[9]
+
+By the definition of momentum,
+
+where m is the mass and 
+
+
+
+
+
+
+v
+→
+
+
+
+
+
+{\displaystyle {\vec {v}}}
+
+ is the velocity.[3]:9–1, 9–2
+
+If Newton's second law is applied to a system of constant mass,[Note 2] m may be moved outside the derivative operator. The equation then becomes
+
+By substituting the definition of acceleration, the algebraic version of Newton's Second Law is derived:
+
+Newton never explicitly stated the formula in the reduced form above.[10]
+
+Newton's Second Law asserts the direct proportionality of acceleration to force and the inverse proportionality of acceleration to mass. Accelerations can be defined through kinematic measurements. However, while kinematics are well-described through reference frame analysis in advanced physics, there are still deep questions that remain as to what is the proper definition of mass. General relativity offers an equivalence between space-time and mass, but lacking a coherent theory of quantum gravity, it is unclear as to how or whether this connection is relevant on microscales. With some justification, Newton's second law can be taken as a quantitative definition of mass by writing the law as an equality; the relative units of force and mass then are fixed.
+
+The use of Newton's Second Law as a definition of force has been disparaged in some of the more rigorous textbooks,[3]:12–1[4]:59[11] because it is essentially a mathematical truism. Notable physicists, philosophers and mathematicians who have sought a more explicit definition of the concept of force include Ernst Mach and Walter Noll.[12][13]
+
+Newton's Second Law can be used to measure the strength of forces. For instance, knowledge of the masses of planets along with the accelerations of their orbits allows scientists to calculate the gravitational forces on planets.
+
+Whenever one body exerts a force on another, the latter simultaneously exerts an equal and opposite force on the first. In vector form, if 
+
+
+
+
+
+
+
+
+F
+→
+
+
+
+
+1
+,
+2
+
+
+
+
+
+{\displaystyle \scriptstyle {\vec {F}}_{1,2}}
+
+ is the force of body 1 on body 2 and 
+
+
+
+
+
+
+
+
+F
+→
+
+
+
+
+2
+,
+1
+
+
+
+
+
+{\displaystyle \scriptstyle {\vec {F}}_{2,1}}
+
+ that of body 2 on body 1, then
+
+This law is sometimes referred to as the action-reaction law, with 
+
+
+
+
+
+
+
+
+F
+→
+
+
+
+
+1
+,
+2
+
+
+
+
+
+{\displaystyle \scriptstyle {\vec {F}}_{1,2}}
+
+ called the action and 
+
+
+
+
+−
+
+
+
+
+F
+→
+
+
+
+
+2
+,
+1
+
+
+
+
+
+{\displaystyle \scriptstyle -{\vec {F}}_{2,1}}
+
+ the reaction.
+
+Newton's Third Law is a result of applying symmetry to situations where forces can be attributed to the presence of different objects. The third law means that all forces are interactions between different bodies,[14][Note 3] and thus that there is no such thing as a unidirectional force or a force that acts on only one body.
+
+In a system composed of object 1 and object 2, the net force on the system due to their mutual interactions is zero:
+
+More generally, in a closed system of particles, all internal forces are balanced. The particles may accelerate with respect to each other but the center of mass of the system will not accelerate. If an external force acts on the system, it will make the center of mass accelerate in proportion to the magnitude of the external force divided by the mass of the system.[3]:19–1[4]
+
+Combining Newton's Second and Third Laws, it is possible to show that the linear momentum of a system is conserved.[15] In a system of two particles, if 
+
+
+
+
+
+
+
+
+p
+→
+
+
+
+
+1
+
+
+
+
+
+{\displaystyle \scriptstyle {\vec {p}}_{1}}
+
+ is the momentum of object 1 and 
+
+
+
+
+
+
+
+
+p
+→
+
+
+
+
+2
+
+
+
+
+
+{\displaystyle \scriptstyle {\vec {p}}_{2}}
+
+ the momentum of object 2, then
+
+Using similar arguments, this can be generalized to a system with an arbitrary number of particles. In general, as long as all forces are due to the interaction of objects with mass, it is possible to define a system such that net momentum is never lost nor gained.[3][4]
+
+In the special theory of relativity, mass and energy are equivalent (as can be seen by calculating the work required to accelerate an object). When an object's velocity increases, so does its energy and hence its mass equivalent (inertia). It thus requires more force to accelerate it the same amount than it did at a lower velocity. Newton's Second Law
+
+remains valid because it is a mathematical definition.[16]:855–876 But for relativistic momentum to be conserved, it must be redefined as:
+
+where 
+
+
+
+
+m
+
+0
+
+
+
+
+{\displaystyle m_{0}}
+
+ is the rest mass and 
+
+
+
+c
+
+
+{\displaystyle c}
+
+ the speed of light.
+
+The relativistic expression relating force and acceleration for a particle with constant non-zero rest mass 
+
+
+
+m
+
+
+{\displaystyle m}
+
+ moving in the 
+
+
+
+x
+
+
+{\displaystyle x}
+
+ direction is:
+
+where
+
+is called  the Lorentz factor.[17]
+
+In the early history of relativity, the expressions 
+
+
+
+
+γ
+
+3
+
+
+m
+
+
+{\displaystyle \gamma ^{3}m}
+
+ and 
+
+
+
+γ
+m
+
+
+{\displaystyle \gamma m}
+
+ were called longitudinal and transverse mass. Relativistic force does not produce a constant acceleration, but an ever-decreasing acceleration as the object approaches the speed of light. Note that 
+
+
+
+γ
+
+
+{\displaystyle \gamma }
+
+ approaches asymptotically an infinite value and is undefined for an object with a non-zero rest mass as it approaches the speed of light, and the theory yields no prediction at that speed.
+
+If 
+
+
+
+v
+
+
+{\displaystyle v}
+
+ is very small compared to 
+
+
+
+c
+
+
+{\displaystyle c}
+
+, then 
+
+
+
+γ
+
+
+{\displaystyle \gamma }
+
+ is very close to 1 and
+
+is a close approximation. Even for use in relativity, however, one can restore the form of
+
+through the use of four-vectors. This relation is correct in relativity when 
+
+
+
+
+F
+
+μ
+
+
+
+
+{\displaystyle F^{\mu }}
+
+ is the four-force, 
+
+
+
+m
+
+
+{\displaystyle m}
+
+ is the invariant mass, and 
+
+
+
+
+A
+
+μ
+
+
+
+
+{\displaystyle A^{\mu }}
+
+ is the four-acceleration.[18]
+
+Since forces are perceived as pushes or pulls, this can provide an intuitive understanding for describing forces.[2] As with other physical concepts (e.g. temperature), the intuitive understanding of forces is quantified using precise operational definitions that are consistent with direct observations and compared to a standard measurement scale. Through experimentation, it is determined that laboratory measurements of forces are fully consistent with the conceptual definition of force offered by Newtonian mechanics.
+
+Forces act in a particular direction and have sizes dependent upon how strong the push or pull is. Because of these characteristics, forces are classified as "vector quantities". This means that forces follow a different set of mathematical rules than physical quantities that do not have direction (denoted scalar quantities). For example, when determining what happens when two forces act on the same object, it is necessary to know both the magnitude and the direction of both forces to calculate the result. If both of these pieces of information are not known for each force, the situation is ambiguous. For example, if you know that two people are pulling on the same rope with known magnitudes of force but you do not know which direction either person is pulling, it is impossible to determine what the acceleration of the rope will be. The two people could be pulling against each other as in tug of war or the two people could be pulling in the same direction. In this simple one-dimensional example, without knowing the direction of the forces it is impossible to decide whether the net force is the result of adding the two force magnitudes or subtracting one from the other. Associating forces with vectors avoids such problems.
+
+Historically, forces were first quantitatively investigated in conditions of static equilibrium where several forces canceled each other out. Such experiments demonstrate the crucial properties that forces are additive vector quantities: they have magnitude and direction.[2] When two forces act on a point particle, the resulting force, the resultant (also called the net force), can be determined by following the parallelogram rule of vector addition: the addition of two vectors represented by sides of a parallelogram, gives an equivalent resultant vector that is equal in magnitude and direction to the transversal of the parallelogram.[3][4] The magnitude of the resultant varies from the difference of the magnitudes of the two forces to their sum, depending on the angle between their lines of action. However, if the forces are acting on an extended body, their respective lines of application must also be specified in order to account for their effects on the motion of the body.
+
+Free-body diagrams can be used as a convenient way to keep track of forces acting on a system. Ideally, these diagrams are drawn with the angles and relative magnitudes of the force vectors preserved so that graphical vector addition can be done to determine the net force.[19]
+
+As well as being added, forces can also be resolved into independent components at right angles to each other. A horizontal force pointing northeast can therefore be split into two forces, one pointing north, and one pointing east. Summing these component forces using vector addition yields the original force. Resolving force vectors into components of a set of basis vectors is often a more mathematically clean way to describe forces than using magnitudes and directions.[20] This is because, for orthogonal components, the components of the vector sum are uniquely determined by the scalar addition of the components of the individual vectors. Orthogonal components are independent of each other because forces acting at ninety degrees to each other have no effect on the magnitude or direction of the other. Choosing a set of orthogonal basis vectors is often done by considering what set of basis vectors will make the mathematics most convenient. Choosing a basis vector that is in the same direction as one of the forces is desirable, since that force would then have only one non-zero component. Orthogonal force vectors can be three-dimensional with the third component being at right-angles to the other two.[3][4]
+
+Equilibrium occurs when the resultant force acting on a point particle is zero (that is, the vector sum of all forces is zero). When dealing with an extended body, it is also necessary that the net torque be zero.
+
+There are two kinds of equilibrium: static equilibrium and dynamic equilibrium.
+
+Static equilibrium was understood well before the invention of classical mechanics. Objects that are at rest have zero net force acting on them.[21]
+
+The simplest case of static equilibrium occurs when two forces are equal in magnitude but opposite in direction. For example, an object on a level surface is pulled (attracted) downward toward the center of the Earth by the force of gravity. At the same time, a force is applied by the surface that resists the downward force with equal upward force (called a normal force). The situation produces zero net force and hence no acceleration.[2]
+
+Pushing against an object that rests on a frictional surface can result in a situation where the object does not move because the applied force is opposed by static friction, generated between the object and the table surface. For a situation with no movement, the static friction force exactly balances the applied force resulting in no acceleration. The static friction increases or decreases in response to the applied force up to an upper limit determined by the characteristics of the contact between the surface and the object.[2]
+
+A static equilibrium between two forces is the most usual way of measuring forces, using simple devices such as weighing scales and spring balances. For example, an object suspended on a vertical spring scale experiences the force of gravity acting on the object balanced by a force applied by the "spring reaction force", which equals the object's weight. Using such tools, some quantitative force laws were discovered: that the force of gravity is proportional to volume for objects of constant density (widely exploited for millennia to define standard weights); Archimedes' principle for buoyancy; Archimedes' analysis of the lever; Boyle's law for gas pressure; and Hooke's law for springs. These were all formulated and experimentally verified before Isaac Newton expounded his Three Laws of Motion.[2][3][4]
+
+Dynamic equilibrium was first described by Galileo who noticed that certain assumptions of Aristotelian physics were contradicted by observations and logic. Galileo realized that simple velocity addition demands that the concept of an "absolute rest frame" did not exist. Galileo concluded that motion in a constant velocity was completely equivalent to rest. This was contrary to Aristotle's notion of a "natural state" of rest that objects with mass naturally approached. Simple experiments showed that Galileo's understanding of the equivalence of constant velocity and rest were correct. For example, if a mariner dropped a cannonball from the crow's nest of a ship moving at a constant velocity, Aristotelian physics would have the cannonball fall straight down while the ship moved beneath it. Thus, in an Aristotelian universe, the falling cannonball would land behind the foot of the mast of a moving ship. However, when this experiment is actually conducted, the cannonball always falls at the foot of the mast, as if the cannonball knows to travel with the ship despite being separated from it. Since there is no forward horizontal force being applied on the cannonball as it falls, the only conclusion left is that the cannonball continues to move with the same velocity as the boat as it falls. Thus, no force is required to keep the cannonball moving at the constant forward velocity.[8]
+
+Moreover, any object traveling at a constant velocity must be subject to zero net force (resultant force). This is the definition of dynamic equilibrium: when all the forces on an object balance but it still moves at a constant velocity.
+
+A simple case of dynamic equilibrium occurs in constant velocity motion across a surface with kinetic friction. In such a situation, a force is applied in the direction of motion while the kinetic friction force exactly opposes the applied force. This results in zero net force, but since the object started with a non-zero velocity, it continues to move with a non-zero velocity. Aristotle misinterpreted this motion as being caused by the applied force. However, when kinetic friction is taken into consideration it is clear that there is no net force causing constant velocity motion.[3][4]
+
+The notion "force" keeps its meaning in quantum mechanics, though one is now dealing with operators  instead of classical variables and though the physics is now described by the Schrödinger equation instead of Newtonian equations. This has the consequence that the results of a measurement are now sometimes "quantized", i.e. they appear in discrete portions. This is, of course, difficult to imagine in the context of "forces". However, the potentials V(x,y,z) or fields, from which the forces generally can be derived, are treated similarly to classical position variables, i.e., 
+
+
+
+V
+(
+x
+,
+y
+,
+z
+)
+→
+
+
+
+V
+^
+
+
+
+(
+
+
+
+x
+^
+
+
+
+,
+
+
+
+y
+^
+
+
+
+,
+
+
+
+z
+^
+
+
+
+)
+
+
+{\displaystyle V(x,y,z)\to {\hat {V}}({\hat {x}},{\hat {y}},{\hat {z}})}
+
+.
+
+This becomes different only in the framework of quantum field theory, where these fields are also quantized.
+
+However, already in quantum mechanics there is one "caveat", namely the particles acting onto each other do not only possess the spatial variable, but also a discrete  intrinsic angular momentum-like variable called the "spin", and there is the Pauli exclusion principle relating the space and the spin variables. Depending on the value of the spin, identical particles split into two different classes, fermions and bosons.  If two identical fermions (e.g. electrons) have a symmetric spin function (e.g.  parallel spins) the spatial variables must be antisymmetric (i.e. they exclude each other from their places much as if there was a repulsive force), and vice versa, i.e. for antiparallel spins the position variables must be symmetric (i.e. the apparent force must be attractive). Thus in the case of two fermions there is a strictly negative correlation between spatial and spin variables, whereas for two bosons (e.g. quanta of electromagnetic waves, photons) the correlation is strictly positive.
+
+Thus the notion "force" loses already part of its meaning.
+
+In modern particle physics, forces and the acceleration of particles are explained as a mathematical by-product of exchange of momentum-carrying gauge bosons. With the development of quantum field theory and general relativity, it was realized that force is a redundant concept arising from conservation of momentum (4-momentum in relativity and momentum of virtual particles in quantum electrodynamics). The conservation of momentum can be directly derived from the homogeneity or symmetry of space and so is usually considered more fundamental than the concept of a force. Thus the currently known fundamental forces are considered more accurately to be "fundamental interactions".[5]:199–128 When particle A emits (creates) or absorbs (annihilates) virtual particle B, a momentum conservation results in recoil of particle A making impression of repulsion or attraction between particles A A' exchanging by B. This description applies to all forces arising from fundamental interactions. While sophisticated mathematical descriptions are needed to predict, in full detail, the accurate result of such interactions, there is a conceptually simple way to describe such interactions through the use of Feynman diagrams. In a Feynman diagram, each matter particle is represented as a straight line (see world line) traveling through time, which normally increases up or to the right in the diagram. Matter and anti-matter particles are identical except for their direction of propagation through the Feynman diagram. World lines of particles intersect at interaction vertices, and the Feynman diagram represents any force arising from an interaction as occurring at the vertex with an associated instantaneous change in the direction of the particle world lines. Gauge bosons are emitted away from the vertex as wavy lines and, in the case of virtual particle exchange, are absorbed at an adjacent vertex.[22]
+
+The utility of Feynman diagrams is that other types of physical phenomena that are part of the general picture of fundamental interactions but are conceptually separate from forces can also be described using the same rules. For example, a Feynman diagram can describe in succinct detail how a neutron decays into an electron, proton, and neutrino, an interaction mediated by the same gauge boson that is responsible for the weak nuclear force.[22]
+
+All of the known forces of the universe are classified into four fundamental interactions. The strong and the weak forces are nuclear forces that act only at very short distances, and are responsible for the interactions between subatomic particles, including nucleons and compound nuclei. The electromagnetic force acts between electric charges, and the gravitational force acts between masses. All other forces in nature derive from these four fundamental interactions. For example, friction is a manifestation of the electromagnetic force acting between atoms of two surfaces, and the Pauli exclusion principle,[23] which does not permit atoms to pass through each other. Similarly, the forces in springs, modeled by Hooke's law, are the result of electromagnetic forces and the Pauli exclusion principle acting together to return an object to its equilibrium position. Centrifugal forces are acceleration forces that arise simply from the acceleration of rotating frames of reference.[3]:12–11[4]:359
+
+The fundamental theories for forces developed from the unification of different ideas. For example, Sir. Isaac Newton unified, with his universal theory of gravitation, the force responsible for objects falling near the surface of the Earth with the force responsible for the falling of celestial bodies about the Earth (the Moon) and around the Sun (the planets). Michael Faraday and James Clerk Maxwell demonstrated that electric and magnetic forces were unified through a theory of electromagnetism. In the 20th century, the development of quantum mechanics led to a modern understanding that the first three fundamental forces (all except gravity) are manifestations of matter (fermions) interacting by exchanging virtual particles called gauge bosons.[24] This Standard Model of particle physics assumes a similarity between the forces and led scientists to predict the unification of the weak and electromagnetic forces in electroweak theory, which was subsequently confirmed by observation. The complete formulation of the Standard Model predicts an as yet unobserved Higgs mechanism, but observations such as neutrino oscillations suggest that the Standard Model is incomplete. A Grand Unified Theory that allows for the combination of the electroweak interaction with the strong force is held out as a possibility with candidate theories such as supersymmetry proposed to accommodate some of the outstanding unsolved problems in physics. Physicists are still attempting to develop self-consistent unification models that would combine all four fundamental interactions into a theory of everything. Einstein tried and failed at this endeavor, but currently the most popular approach to answering this question is string theory.[5]:212–219
+
+What we now call gravity was not identified as a universal force until the work of Isaac Newton. Before Newton, the tendency for objects to fall towards the Earth was not understood to be related to the motions of celestial objects. Galileo was instrumental in describing the characteristics of falling objects by determining that the acceleration of every object in free-fall was constant and independent of the mass of the object. Today, this acceleration due to gravity towards the surface of the Earth is usually designated as 
+
+
+
+
+
+
+
+g
+→
+
+
+
+
+
+
+{\displaystyle \scriptstyle {\vec {g}}}
+
+ and has a magnitude of about 9.81 meters per second squared (this measurement is taken from sea level and may vary depending on location), and points toward the center of the Earth.[26] This observation means that the force of gravity on an object at the Earth's surface is directly proportional to the object's mass. Thus an object that has a mass of 
+
+
+
+m
+
+
+{\displaystyle m}
+
+ will experience a force:
+
+For an object in free-fall, this force is unopposed and the net force on the object is its weight. For objects not in free-fall, the force of gravity is opposed by the reaction forces applied by their supports. For example, a person standing on the ground experiences zero net force, since a normal force (a reaction force) is exerted by the ground upward on the person that counterbalances his weight that is directed downward.[3][4]
+
+Newton's contribution to gravitational theory was to unify the motions of heavenly bodies, which Aristotle had assumed were in a natural state of constant motion, with falling motion observed on the Earth. He proposed a law of gravity that could account for the celestial motions that had been described earlier using Kepler's laws of planetary motion.[27]
+
+Newton came to realize that the effects of gravity might be observed in different ways at larger distances. In particular, Newton determined that the acceleration of the Moon around the Earth could be ascribed to the same force of gravity if the acceleration due to gravity decreased as an inverse square law. Further, Newton realized that the acceleration of a body due to gravity is proportional to the mass of the other attracting body.[27] Combining these ideas gives a formula that relates the mass (
+
+
+
+
+
+m
+
+⊕
+
+
+
+
+
+{\displaystyle \scriptstyle m_{\oplus }}
+
+) and the radius (
+
+
+
+
+
+R
+
+⊕
+
+
+
+
+
+{\displaystyle \scriptstyle R_{\oplus }}
+
+) of the Earth to the gravitational acceleration:
+
+where the vector direction is given by 
+
+
+
+
+
+
+r
+^
+
+
+
+
+
+{\displaystyle {\hat {r}}}
+
+, is the unit vector directed outward from the center of the Earth.[9]
+
+In this equation, a dimensional constant 
+
+
+
+G
+
+
+{\displaystyle G}
+
+ is used to describe the relative strength of gravity. This constant has come to be known as Newton's Universal Gravitation Constant,[28] though its value was unknown in Newton's lifetime. Not until 1798 was Henry Cavendish able to make the first measurement of 
+
+
+
+G
+
+
+{\displaystyle G}
+
+ using a torsion balance; this was widely reported in the press as a measurement of the mass of the Earth since knowing 
+
+
+
+G
+
+
+{\displaystyle G}
+
+ could allow one to solve for the Earth's mass given the above equation. Newton, however, realized that since all celestial bodies followed the same laws of motion, his law of gravity had to be universal. Succinctly stated, Newton's Law of Gravitation states that the force on a spherical object of mass 
+
+
+
+
+m
+
+1
+
+
+
+
+{\displaystyle m_{1}}
+
+ due to the gravitational pull of mass 
+
+
+
+
+m
+
+2
+
+
+
+
+{\displaystyle m_{2}}
+
+ is
+
+where 
+
+
+
+r
+
+
+{\displaystyle r}
+
+ is the distance between the two objects' centers of mass and 
+
+
+
+
+
+
+
+r
+^
+
+
+
+
+
+
+{\displaystyle \scriptstyle {\hat {r}}}
+
+ is the unit vector pointed in the direction away from the center of the first object toward the center of the second object.[9]
+
+This formula was powerful enough to stand as the basis for all subsequent descriptions of motion within the solar system until the 20th century. During that time, sophisticated methods of perturbation analysis[29] were invented to calculate the deviations of orbits due to the influence of multiple bodies on a planet, moon, comet, or asteroid. The formalism was exact enough to allow mathematicians to predict the existence of the planet Neptune before it was observed.[30]
+
+Mercury's orbit, however, did not match that predicted by Newton's Law of Gravitation. Some astrophysicists predicted the existence of another planet (Vulcan) that would explain the discrepancies; however no such planet could be found. When Albert Einstein formulated his theory of general relativity (GR) he turned his attention to the problem of Mercury's orbit and found that his theory added a correction, which could account for the discrepancy. This was the first time that Newton's Theory of Gravity had been shown to be inexact.[32]
+
+Since then, general relativity has been acknowledged as the theory that best explains gravity. In GR, gravitation is not viewed as a force, but rather, objects moving freely in gravitational fields travel under their own inertia in straight lines through curved space-time – defined as the shortest space-time path between two space-time events. From the perspective of the object, all motion occurs as if there were no gravitation whatsoever. It is only when observing the motion in a global sense that the curvature of space-time can be observed and the force is inferred from the object's curved path. Thus, the straight line path in space-time is seen as a curved line in space, and it is called the ballistic trajectory of the object. For example, a basketball thrown from the ground moves in a parabola, as it is in a uniform gravitational field. Its space-time trajectory is almost a straight line, slightly curved (with the radius of curvature of the order of few light-years). The time derivative of the changing momentum of the object is what we label as "gravitational force".[4]
+
+The electrostatic force was first described in 1784 by Coulomb as a force that existed intrinsically between two charges.[16]:519 The properties of the electrostatic force were that it varied as an inverse square law directed in the radial direction, was both attractive and repulsive (there was intrinsic polarity), was independent of the mass of the charged objects, and followed the superposition principle. Coulomb's law unifies all these observations into one succinct statement.[33]
+
+Subsequent mathematicians and physicists found the construct of the electric field to be useful for determining the electrostatic force on an electric charge at any point in space. The electric field was based on using a hypothetical "test charge" anywhere in space and then using Coulomb's Law to determine the electrostatic force.[34]:4–6 to 4–8 Thus the electric field anywhere in space is defined as
+
+where 
+
+
+
+q
+
+
+{\displaystyle q}
+
+ is the magnitude of the hypothetical test charge.
+
+Meanwhile, the Lorentz force of magnetism was discovered to exist between two electric currents. It has the same mathematical character as Coulomb's Law with the proviso that like currents attract and unlike currents repel. Similar to the electric field, the magnetic field can be used to determine the magnetic force on an electric current at any point in space. In this case, the magnitude of the magnetic field was determined to be
+
+where 
+
+
+
+I
+
+
+{\displaystyle I}
+
+ is the magnitude of the hypothetical test current and 
+
+
+
+
+ℓ
+
+
+
+{\displaystyle \scriptstyle \ell }
+
+ is the length of hypothetical wire through which the test current flows. The magnetic field exerts a force on all magnets including, for example, those used in compasses. The fact that the Earth's magnetic field is aligned closely with the orientation of the Earth's axis causes compass magnets to become oriented because of the magnetic force pulling on the needle.
+
+Through combining the definition of electric current as the time rate of change of electric charge, a rule of vector multiplication called Lorentz's Law describes the force on a charge moving in a magnetic field.[34] The connection between electricity and magnetism allows for the description of a unified electromagnetic force that acts on a charge. This force can be written as a sum of the electrostatic force (due to the electric field) and the magnetic force (due to the magnetic field). Fully stated, this is the law:
+
+where 
+
+
+
+
+
+
+
+F
+→
+
+
+
+
+
+
+{\displaystyle \scriptstyle {\vec {F}}}
+
+ is the electromagnetic force, 
+
+
+
+q
+
+
+{\displaystyle q}
+
+ is the magnitude of the charge of the particle, 
+
+
+
+
+
+
+
+E
+→
+
+
+
+
+
+
+{\displaystyle \scriptstyle {\vec {E}}}
+
+ is the electric field, 
+
+
+
+
+
+
+
+v
+→
+
+
+
+
+
+
+{\displaystyle \scriptstyle {\vec {v}}}
+
+ is the velocity of the particle that is crossed with the magnetic field (
+
+
+
+
+
+
+
+B
+→
+
+
+
+
+
+
+{\displaystyle \scriptstyle {\vec {B}}}
+
+).
+
+The origin of electric and magnetic fields would not be fully explained until 1864 when James Clerk Maxwell unified a number of earlier theories into a set of 20 scalar equations, which were later reformulated into 4 vector equations by Oliver Heaviside and Josiah Willard Gibbs.[35] These "Maxwell Equations" fully described the sources of the fields as being stationary and moving charges, and the interactions of the fields themselves. This led Maxwell to discover that electric and magnetic fields could be "self-generating" through a wave that traveled at a speed that he calculated to be the speed of light. This insight united the nascent fields of electromagnetic theory with optics and led directly to a complete description of the electromagnetic spectrum.[36]
+
+However, attempting to reconcile electromagnetic theory with two observations, the photoelectric effect, and the nonexistence of the ultraviolet catastrophe, proved troublesome. Through the work of leading theoretical physicists, a new theory of electromagnetism was developed using quantum mechanics. This final modification to electromagnetic theory ultimately led to quantum electrodynamics (or QED), which fully describes all electromagnetic phenomena as being mediated by wave–particles known as photons. In QED, photons are the fundamental exchange particle, which described all interactions relating to electromagnetism including the electromagnetic force.[Note 4]
+
+There are two "nuclear forces", which today are usually described as interactions that take place in quantum theories of particle physics. The strong nuclear force[16]:940 is the force responsible for the structural integrity of atomic nuclei while the weak nuclear force[16]:951 is responsible for the decay of certain nucleons into leptons and other types of hadrons.[3][4]
+
+The strong force is today understood to represent the interactions between quarks and gluons as detailed by the theory of quantum chromodynamics (QCD).[37] The strong force is the fundamental force mediated by gluons, acting upon quarks, antiquarks, and the gluons themselves. The (aptly named) strong interaction is the "strongest" of the four fundamental forces.
+
+The strong force only acts directly upon elementary particles. However, a residual of the force is observed between hadrons (the best known example being the force that acts between nucleons in atomic nuclei) as the nuclear force. Here the strong force acts indirectly, transmitted as gluons, which form part of the virtual pi and rho mesons, which classically transmit the nuclear force (see this topic for more). The failure of many searches for free quarks has shown that the elementary particles affected are not directly observable. This phenomenon is called color confinement.
+
+The weak force is due to the exchange of the heavy W and Z bosons. Its most familiar effect is beta decay (of neutrons in atomic nuclei) and the associated radioactivity. The word "weak" derives from the fact that the field strength is some 1013 times less than that of the strong force. Still, it is stronger than gravity over short distances. A consistent electroweak theory has also been developed, which shows that electromagnetic forces and the weak force are indistinguishable at a temperatures in excess of approximately 1015 kelvins. Such temperatures have been probed in modern particle accelerators and show the conditions of the universe in the early moments of the Big Bang.
+
+Some forces are consequences of the fundamental ones. In such situations, idealized models can be utilized to gain physical insight.
+
+The normal force is due to repulsive forces of interaction between atoms at close contact. When their electron clouds overlap, Pauli repulsion (due to fermionic nature of electrons) follows resulting in the force that acts in a direction normal to the surface interface between two objects.[16]:93 The normal force, for example, is responsible for the structural integrity of tables and floors as well as being the force that responds whenever an external force pushes on a solid object. An example of the normal force in action is the impact force on an object crashing into an immobile surface.[3][4]
+
+Friction is a surface force that opposes relative motion. The frictional force is directly related to the normal force that acts to keep two solid objects separated at the point of contact. There are two broad classifications of frictional forces: static friction and kinetic friction.
+
+The static friction force (
+
+
+
+
+F
+
+
+s
+f
+
+
+
+
+
+{\displaystyle F_{\mathrm {sf} }}
+
+) will exactly oppose forces applied to an object parallel to a surface contact up to the limit specified by the coefficient of static friction (
+
+
+
+
+μ
+
+
+s
+f
+
+
+
+
+
+{\displaystyle \mu _{\mathrm {sf} }}
+
+) multiplied by the normal force (
+
+
+
+
+F
+
+N
+
+
+
+
+{\displaystyle F_{N}}
+
+). In other words, the magnitude of the static friction force satisfies the inequality:
+
+The kinetic friction force (
+
+
+
+
+F
+
+
+k
+f
+
+
+
+
+
+{\displaystyle F_{\mathrm {kf} }}
+
+) is independent of both the forces applied and the movement of the object. Thus, the magnitude of the force equals:
+
+where 
+
+
+
+
+μ
+
+
+k
+f
+
+
+
+
+
+{\displaystyle \mu _{\mathrm {kf} }}
+
+ is the coefficient of kinetic friction. For most surface interfaces, the coefficient of kinetic friction is less than the coefficient of static friction.
+
+Tension forces can be modeled using ideal strings that are massless, frictionless, unbreakable, and unstretchable. They can be combined with ideal pulleys, which allow ideal strings to switch physical direction. Ideal strings transmit tension forces instantaneously in action-reaction pairs so that if two objects are connected by an ideal string, any force directed along the string by the first object is accompanied by a force directed along the string in the opposite direction by the second object.[38] By connecting the same string multiple times to the same object through the use of a set-up that uses movable pulleys, the tension force on a load can be multiplied. For every string that acts on a load, another factor of the tension force in the string acts on the load. However, even though such machines allow for an increase in force, there is a corresponding increase in the length of string that must be displaced in order to move the load. These tandem effects result ultimately in the conservation of mechanical energy since the work done on the load is the same no matter how complicated the machine.[3][4][39]
+
+An elastic force acts to return a spring to its natural length. An ideal spring is taken to be massless, frictionless, unbreakable, and infinitely stretchable. Such springs exert forces that push when contracted, or pull when extended, in proportion to the displacement of the spring from its equilibrium position.[40] This linear relationship was described by Robert Hooke in 1676, for whom Hooke's law is named. If 
+
+
+
+Δ
+x
+
+
+{\displaystyle \Delta x}
+
+ is the displacement, the force exerted by an ideal spring equals:
+
+where 
+
+
+
+k
+
+
+{\displaystyle k}
+
+ is the spring constant (or force constant), which is particular to the spring. The minus sign accounts for the tendency of the force to act in opposition to the applied load.[3][4]
+
+Newton's laws and Newtonian mechanics in general were first developed to describe how forces affect idealized point particles rather than three-dimensional objects. However, in real life, matter has extended structure and forces that act on one part of an object might affect other parts of an object. For situations where lattice holding together the atoms in an object is able to flow, contract, expand, or otherwise change shape, the theories of continuum mechanics describe the way forces affect the material. For example, in extended fluids, differences in pressure result in forces being directed along the pressure gradients as follows:
+
+where 
+
+
+
+V
+
+
+{\displaystyle V}
+
+ is the volume of the object in the fluid and 
+
+
+
+P
+
+
+{\displaystyle P}
+
+ is the scalar function that describes the pressure at all locations in space. Pressure gradients and differentials result in the buoyant force for fluids suspended in gravitational fields, winds in atmospheric science, and the lift associated with aerodynamics and flight.[3][4]
+
+A specific instance of such a force that is associated with dynamic pressure is fluid resistance: a body force that resists the motion of an object through a fluid due to viscosity. For so-called "Stokes' drag" the force is approximately proportional to the velocity, but opposite in direction:
+
+where:
+
+More formally, forces in continuum mechanics are fully described by a stress–tensor with terms that are roughly defined as
+
+where 
+
+
+
+A
+
+
+{\displaystyle A}
+
+ is the relevant cross-sectional area for the volume for which the stress-tensor is being calculated. This formalism includes pressure terms associated with forces that act normal to the cross-sectional area (the matrix diagonals of the tensor) as well as shear terms associated with forces that act parallel to the cross-sectional area (the off-diagonal elements). The stress tensor accounts for forces that cause all strains (deformations) including also tensile stresses and compressions.[2][4]:133–134[34]:38–1–38–11
+
+There are forces that are frame dependent, meaning that they appear due to the adoption of non-Newtonian (that is, non-inertial) reference frames. Such forces include the centrifugal force and the Coriolis force.[41] These forces are considered fictitious because they do not exist in frames of reference that are not accelerating.[3][4] Because these forces are not genuine they are also referred to as "pseudo forces".[3]:12–11
+
+In general relativity, gravity becomes a fictitious force that arises in situations where spacetime deviates from a flat geometry. As an extension, Kaluza–Klein theory and string theory ascribe electromagnetism and the other fundamental forces respectively to the curvature of differently scaled dimensions, which would ultimately imply that all forces are fictitious.
+
+Forces that cause extended objects to rotate are associated with torques. Mathematically, the torque of a force 
+
+
+
+
+
+
+
+F
+→
+
+
+
+
+
+
+{\displaystyle \scriptstyle {\vec {F}}}
+
+ is defined relative to an arbitrary reference point as the cross-product:
+
+where
+
+Torque is the rotation equivalent of force in the same way that angle is the rotational equivalent for position, angular velocity for velocity, and angular momentum for momentum. As a consequence of Newton's First Law of Motion, there exists rotational inertia that ensures that all bodies maintain their angular momentum unless acted upon by an unbalanced torque. Likewise, Newton's Second Law of Motion can be used to derive an analogous equation for the instantaneous angular acceleration of the rigid body:
+
+where
+
+This provides a definition for the moment of inertia, which is the rotational equivalent for mass. In more advanced treatments of mechanics, where the rotation over a time interval is described, the moment of inertia must be substituted by the tensor that, when properly analyzed, fully determines the characteristics of rotations including precession and nutation.
+
+Equivalently, the differential form of Newton's Second Law provides an alternative definition of torque:
+
+Newton's Third Law of Motion requires that all objects exerting torques themselves experience equal and opposite torques,[43] and therefore also directly implies the conservation of angular momentum for closed systems that experience rotations and revolutions through the action of internal torques.
+
+For an object accelerating in circular motion, the unbalanced force acting on the object equals:[44]
+
+where 
+
+
+
+m
+
+
+{\displaystyle m}
+
+ is the mass of the object, 
+
+
+
+v
+
+
+{\displaystyle v}
+
+ is the velocity of the object and 
+
+
+
+r
+
+
+{\displaystyle r}
+
+ is the distance to the center of the circular path and 
+
+
+
+
+
+
+
+r
+^
+
+
+
+
+
+
+{\displaystyle \scriptstyle {\hat {r}}}
+
+ is the unit vector pointing in the radial direction outwards from the center. This means that the unbalanced centripetal force felt by any object is always directed toward the center of the curving path. Such forces act perpendicular to the velocity vector associated with the motion of an object, and therefore do not change the speed of the object (magnitude of the velocity), but only the direction of the velocity vector. The unbalanced force that accelerates an object can be resolved into a component that is perpendicular to the path, and one that is tangential to the path. This yields both the tangential force, which accelerates the object by either slowing it down or speeding it up, and the radial (centripetal) force, which changes its direction.[3][4]
+
+Forces can be used to define a number of physical concepts by integrating with respect to kinematic variables. For example, integrating with respect to time gives the definition of impulse:[45]
+
+which by Newton's Second Law must be equivalent to the change in momentum (yielding the Impulse momentum theorem).
+
+Similarly, integrating with respect to position gives a definition for the work done by a force:[3]:13–3
+
+which is equivalent to changes in kinetic energy (yielding the work energy theorem).[3]:13–3
+
+Power P is the rate of change dW/dt of the work W, as the trajectory is extended by a position change 
+
+
+
+
+
+d
+
+
+
+
+x
+→
+
+
+
+
+
+
+{\displaystyle \scriptstyle {d}{\vec {x}}}
+
+ in a time interval dt:[3]:13–2
+
+with 
+
+
+
+
+
+
+
+v
+→
+
+
+
+
+ 
+
+=
+
+ d
+
+
+
+
+x
+→
+
+
+
+
+/
+
+
+d
+
+t
+
+
+
+{\displaystyle {{\vec {v}}{\text{ }}={\text{ d}}{\vec {x}}/{\text{d}}t}}
+
+ the velocity.
+
+Instead of a force, often the mathematically related concept of a potential energy field can be used for convenience. For instance, the gravitational force acting upon an object can be seen as the action of the gravitational field that is present at the object's location. Restating mathematically the definition of energy (via the definition of work), a potential scalar field 
+
+
+
+
+
+U
+(
+
+
+
+r
+→
+
+
+
+)
+
+
+
+
+{\displaystyle \scriptstyle {U({\vec {r}})}}
+
+ is defined as that field whose gradient is equal and opposite to the force produced at every point:
+
+Forces can be classified as conservative or nonconservative. Conservative forces are equivalent to the gradient of a potential while nonconservative forces are not.[3][4]
+
+A conservative force that acts on a closed system has an associated mechanical work that allows energy to convert only between kinetic or potential forms. This means that for a closed system, the net mechanical energy is conserved whenever a conservative force acts on the system. The force, therefore, is related directly to the difference in potential energy between two different locations in space,[46] and can be considered to be an artifact of the potential field in the same way that the direction and amount of a flow of water can be considered to be an artifact of the contour map of the elevation of an area.[3][4]
+
+Conservative forces include gravity, the electromagnetic force, and the spring force. Each of these forces has models that are dependent on a position often given as a radial vector 
+
+
+
+
+
+
+
+r
+→
+
+
+
+
+
+
+{\displaystyle \scriptstyle {\vec {r}}}
+
+ emanating from spherically symmetric potentials.[47] Examples of this follow:
+
+For gravity:
+
+where 
+
+
+
+G
+
+
+{\displaystyle G}
+
+ is the gravitational constant, and 
+
+
+
+
+m
+
+n
+
+
+
+
+{\displaystyle m_{n}}
+
+ is the mass of object n.
+
+For electrostatic forces:
+
+where 
+
+
+
+
+ϵ
+
+0
+
+
+
+
+{\displaystyle \epsilon _{0}}
+
+ is electric permittivity of free space, and 
+
+
+
+
+q
+
+n
+
+
+
+
+{\displaystyle q_{n}}
+
+ is the electric charge of object n.
+
+For spring forces:
+
+where 
+
+
+
+k
+
+
+{\displaystyle k}
+
+ is the spring constant.[3][4]
+
+For certain physical scenarios, it is impossible to model forces as being due to gradient of potentials. This is often due to macrophysical considerations that yield forces as arising from a macroscopic statistical average of microstates. For example, friction is caused by the gradients of numerous electrostatic potentials between the atoms, but manifests as a force model that is independent of any macroscale position vector. Nonconservative forces other than friction include other contact forces, tension, compression, and drag. However, for any sufficiently detailed description, all these forces are the results of conservative ones since each of these macroscopic forces are the net results of the gradients of microscopic potentials.[3][4]
+
+The connection between macroscopic nonconservative forces and microscopic conservative forces is described by detailed treatment with statistical mechanics. In macroscopic closed systems, nonconservative forces act to change the internal energies of the system, and are often associated with the transfer of heat. According to the Second law of thermodynamics, nonconservative forces necessarily result in energy transformations within closed systems from ordered to more random conditions as entropy increases.[3][4]
+
+The SI unit of force is the newton (symbol N), which is the force required to accelerate a one kilogram mass at a rate of one meter per second squared, or kg·m·s−2.[48] The corresponding CGS unit is the dyne, the force required to accelerate a one gram mass by one centimeter per second squared, or g·cm·s−2. A newton is thus equal to 100,000 dynes.
+
+The gravitational foot-pound-second English unit of force is the pound-force (lbf), defined as the force exerted by gravity on a pound-mass in the standard gravitational field of 9.80665 m·s−2.[48] The pound-force provides an alternative unit of mass: one slug is the mass that will accelerate by one foot per second squared when acted on by one pound-force.[48]
+
+An alternative unit of force in a different foot-pound-second system, the absolute fps system, is the poundal, defined as the force required to accelerate a one-pound mass at a rate of one foot per second squared.[48] The units of slug and poundal are designed to avoid a constant of proportionality in Newton's Second Law.
+
+The pound-force has a metric counterpart, less commonly used than the newton: the kilogram-force (kgf) (sometimes kilopond), is the force exerted by standard gravity on one kilogram of mass.[48] The kilogram-force leads to an alternate, but rarely used unit of mass: the metric slug (sometimes mug or hyl) is that mass that accelerates at 1 m·s−2 when subjected to a force of 1 kgf. The kilogram-force is not a part of the modern SI system, and is generally deprecated; however it still sees use for some purposes as expressing aircraft weight, jet thrust, bicycle spoke tension, torque wrench settings and engine output torque. Other arcane units of force include the sthène, which is equivalent to 1000 N, and the kip, which is equivalent to 1000 lbf.
+
+See also Ton-force.
+
+See force gauge, spring scale, load cell
+

en/2034.html.txt

@@ -0,0 +1,1277 @@
+
+
+In physics, a force is any interaction that, when unopposed, will change the motion of an object. A force can cause an object with mass to change its velocity (which includes to begin moving from a state of rest), i.e., to accelerate. Force can also be described intuitively as a push or a pull. A force has both magnitude and direction, making it a vector quantity.  It is measured in the SI unit of newtons and represented by the symbol F.
+
+The original form of Newton's second law states that the net force acting upon an object is equal to the rate at which its momentum changes with time. If the mass of the object is constant, this law implies that the acceleration of an object is directly proportional to the net force acting on the object, is in the direction of the net force, and is inversely proportional to the mass of the object.
+
+Concepts related to force include: thrust, which increases the velocity of an object; drag, which decreases the velocity of an object; and torque, which produces changes in rotational speed of an object. In an extended body, each part usually applies forces on the adjacent parts; the distribution of such forces through the body is the internal mechanical stress. Such internal mechanical stresses cause no acceleration of that body as the forces balance one another. Pressure, the distribution of many small forces applied over an area of a body, is a simple type of stress that if unbalanced can cause the body to accelerate. Stress usually causes deformation of solid materials, or flow in fluids.
+
+Philosophers in antiquity used the concept of force in the study of stationary and moving objects and simple machines, but thinkers such as Aristotle and Archimedes retained fundamental errors in understanding force. In part this was due to an incomplete understanding of the sometimes non-obvious force of friction, and a consequently inadequate view of the nature of natural motion.[1] A fundamental error was the belief that a force is required to maintain motion, even at a constant velocity. Most of the previous misunderstandings about motion and force were eventually corrected by Galileo Galilei and Sir Isaac Newton. With his mathematical insight, Sir Isaac Newton formulated laws of motion that were not improved for nearly three hundred years.[2] By the early 20th century, Einstein developed a theory of relativity that correctly predicted the action of forces on objects with increasing momenta near the speed of light, and also provided insight into the forces produced by gravitation and inertia.
+
+With modern insights into quantum mechanics and technology that can accelerate particles close to the speed of light, particle physics has devised a Standard Model to describe forces between particles smaller than atoms. The Standard Model predicts that exchanged particles called gauge bosons are the fundamental means by which forces are emitted and absorbed. Only four main interactions are known: in order of decreasing strength, they are: strong, electromagnetic, weak, and gravitational.[3]:2–10[4]:79 High-energy particle physics observations made during the 1970s and 1980s confirmed that the weak and electromagnetic forces are expressions of a more fundamental electroweak interaction.[5]
+
+Since antiquity the concept of force has been recognized as integral to the functioning of each of the simple machines. The mechanical advantage given by a simple machine allowed for less force to be used in exchange for that force acting over a greater distance for the same amount of work. Analysis of the characteristics of forces ultimately culminated in the work of Archimedes who was especially famous for formulating a treatment of buoyant forces inherent in fluids.[1]
+
+Aristotle provided a philosophical discussion of the concept of a force as an integral part of Aristotelian cosmology. In Aristotle's view, the terrestrial sphere contained four elements that come to rest at different "natural places" therein. Aristotle believed that motionless objects on Earth, those composed mostly of the elements earth and water, to be in their natural place on the ground and that they will stay that way if left alone. He distinguished between the innate tendency of objects to find their "natural place" (e.g., for heavy bodies to fall), which led to "natural motion", and unnatural or forced motion, which required continued application of a force.[6] This theory, based on the everyday experience of how objects move, such as the constant application of a force needed to keep a cart moving, had conceptual trouble accounting for the behavior of projectiles, such as the flight of arrows. The place where the archer moves the projectile was at the start of the flight, and while the projectile sailed through the air, no discernible efficient cause acts on it. Aristotle was aware of this problem and proposed that the air displaced through the projectile's path carries the projectile to its target. This explanation demands a continuum like air for change of place in general.[7]
+
+Aristotelian physics began facing criticism in medieval science, first by John Philoponus in the 6th century.
+
+The shortcomings of Aristotelian physics would not be fully corrected until the 17th century work of Galileo Galilei, who was influenced by the late medieval idea that objects in forced motion carried an innate force of impetus. Galileo constructed an experiment in which stones and cannonballs were both rolled down an incline to disprove the Aristotelian theory of motion. He showed that the bodies were accelerated by gravity to an extent that was independent of their mass and argued that objects retain their velocity unless acted on by a force, for example friction.[8]
+
+Sir Isaac Newton described the motion of all objects using the concepts of inertia and force, and in doing so he found they obey certain conservation laws. In 1687, Newton published his thesis Philosophiæ Naturalis Principia Mathematica.[2][9] In this work Newton set out three laws of motion that to this day are the way forces are described in physics.[9]
+
+Newton's First Law of Motion states that objects continue to move in a state of constant velocity unless acted upon by an external net force (resultant force).[9] This law is an extension of Galileo's insight that constant velocity was associated with a lack of net force (see a more detailed description of this below). Newton proposed that every object with mass has an innate inertia that functions as the fundamental equilibrium "natural state" in place of the Aristotelian idea of the "natural state of rest". That is, Newton's empirical First Law contradicts the intuitive Aristotelian belief that a net force is required to keep an object moving with constant velocity. By making rest physically indistinguishable from non-zero constant velocity, Newton's First Law directly connects inertia with the concept of relative velocities. Specifically, in systems where objects are moving with different velocities, it is impossible to determine which object is "in motion" and which object is "at rest". The laws of physics are the same in every inertial frame of reference, that is, in all frames related by a Galilean transformation.
+
+For instance, while traveling in a moving vehicle at a constant velocity, the laws of physics do not change as a result of its motion. If a person riding within the vehicle throws a ball straight up, that person will observe it rise vertically and fall vertically and not have to apply a force in the direction the vehicle is moving. Another person, observing the moving vehicle pass by, would observe the ball follow a curving parabolic path in the same direction as the motion of the vehicle. It is the inertia of the ball associated with its constant velocity in the direction of the vehicle's motion that ensures the ball continues to move forward even as it is thrown up and falls back down. From the perspective of the person in the car, the vehicle and everything inside of it is at rest: It is the outside world that is moving with a constant speed in the opposite direction of the vehicle. Since there is no experiment that can distinguish whether it is the vehicle that is at rest or the outside world that is at rest, the two situations are considered to be physically indistinguishable. Inertia therefore applies equally well to constant velocity motion as it does to rest.
+
+A modern statement of Newton's Second Law is a vector equation:[Note 1]
+
+where 
+
+
+
+
+
+
+p
+→
+
+
+
+
+
+{\displaystyle {\vec {p}}}
+
+ is the momentum of the system, and 
+
+
+
+
+
+
+F
+→
+
+
+
+
+
+{\displaystyle {\vec {F}}}
+
+ is the net (vector sum) force. If a body is in equilibrium, there is zero net force by definition (balanced forces may be present nevertheless). In contrast, the second law states that if there is an unbalanced force acting on an object it will result in the object's momentum changing over time.[9]
+
+By the definition of momentum,
+
+where m is the mass and 
+
+
+
+
+
+
+v
+→
+
+
+
+
+
+{\displaystyle {\vec {v}}}
+
+ is the velocity.[3]:9–1, 9–2
+
+If Newton's second law is applied to a system of constant mass,[Note 2] m may be moved outside the derivative operator. The equation then becomes
+
+By substituting the definition of acceleration, the algebraic version of Newton's Second Law is derived:
+
+Newton never explicitly stated the formula in the reduced form above.[10]
+
+Newton's Second Law asserts the direct proportionality of acceleration to force and the inverse proportionality of acceleration to mass. Accelerations can be defined through kinematic measurements. However, while kinematics are well-described through reference frame analysis in advanced physics, there are still deep questions that remain as to what is the proper definition of mass. General relativity offers an equivalence between space-time and mass, but lacking a coherent theory of quantum gravity, it is unclear as to how or whether this connection is relevant on microscales. With some justification, Newton's second law can be taken as a quantitative definition of mass by writing the law as an equality; the relative units of force and mass then are fixed.
+
+The use of Newton's Second Law as a definition of force has been disparaged in some of the more rigorous textbooks,[3]:12–1[4]:59[11] because it is essentially a mathematical truism. Notable physicists, philosophers and mathematicians who have sought a more explicit definition of the concept of force include Ernst Mach and Walter Noll.[12][13]
+
+Newton's Second Law can be used to measure the strength of forces. For instance, knowledge of the masses of planets along with the accelerations of their orbits allows scientists to calculate the gravitational forces on planets.
+
+Whenever one body exerts a force on another, the latter simultaneously exerts an equal and opposite force on the first. In vector form, if 
+
+
+
+
+
+
+
+
+F
+→
+
+
+
+
+1
+,
+2
+
+
+
+
+
+{\displaystyle \scriptstyle {\vec {F}}_{1,2}}
+
+ is the force of body 1 on body 2 and 
+
+
+
+
+
+
+
+
+F
+→
+
+
+
+
+2
+,
+1
+
+
+
+
+
+{\displaystyle \scriptstyle {\vec {F}}_{2,1}}
+
+ that of body 2 on body 1, then
+
+This law is sometimes referred to as the action-reaction law, with 
+
+
+
+
+
+
+
+
+F
+→
+
+
+
+
+1
+,
+2
+
+
+
+
+
+{\displaystyle \scriptstyle {\vec {F}}_{1,2}}
+
+ called the action and 
+
+
+
+
+−
+
+
+
+
+F
+→
+
+
+
+
+2
+,
+1
+
+
+
+
+
+{\displaystyle \scriptstyle -{\vec {F}}_{2,1}}
+
+ the reaction.
+
+Newton's Third Law is a result of applying symmetry to situations where forces can be attributed to the presence of different objects. The third law means that all forces are interactions between different bodies,[14][Note 3] and thus that there is no such thing as a unidirectional force or a force that acts on only one body.
+
+In a system composed of object 1 and object 2, the net force on the system due to their mutual interactions is zero:
+
+More generally, in a closed system of particles, all internal forces are balanced. The particles may accelerate with respect to each other but the center of mass of the system will not accelerate. If an external force acts on the system, it will make the center of mass accelerate in proportion to the magnitude of the external force divided by the mass of the system.[3]:19–1[4]
+
+Combining Newton's Second and Third Laws, it is possible to show that the linear momentum of a system is conserved.[15] In a system of two particles, if 
+
+
+
+
+
+
+
+
+p
+→
+
+
+
+
+1
+
+
+
+
+
+{\displaystyle \scriptstyle {\vec {p}}_{1}}
+
+ is the momentum of object 1 and 
+
+
+
+
+
+
+
+
+p
+→
+
+
+
+
+2
+
+
+
+
+
+{\displaystyle \scriptstyle {\vec {p}}_{2}}
+
+ the momentum of object 2, then
+
+Using similar arguments, this can be generalized to a system with an arbitrary number of particles. In general, as long as all forces are due to the interaction of objects with mass, it is possible to define a system such that net momentum is never lost nor gained.[3][4]
+
+In the special theory of relativity, mass and energy are equivalent (as can be seen by calculating the work required to accelerate an object). When an object's velocity increases, so does its energy and hence its mass equivalent (inertia). It thus requires more force to accelerate it the same amount than it did at a lower velocity. Newton's Second Law
+
+remains valid because it is a mathematical definition.[16]:855–876 But for relativistic momentum to be conserved, it must be redefined as:
+
+where 
+
+
+
+
+m
+
+0
+
+
+
+
+{\displaystyle m_{0}}
+
+ is the rest mass and 
+
+
+
+c
+
+
+{\displaystyle c}
+
+ the speed of light.
+
+The relativistic expression relating force and acceleration for a particle with constant non-zero rest mass 
+
+
+
+m
+
+
+{\displaystyle m}
+
+ moving in the 
+
+
+
+x
+
+
+{\displaystyle x}
+
+ direction is:
+
+where
+
+is called  the Lorentz factor.[17]
+
+In the early history of relativity, the expressions 
+
+
+
+
+γ
+
+3
+
+
+m
+
+
+{\displaystyle \gamma ^{3}m}
+
+ and 
+
+
+
+γ
+m
+
+
+{\displaystyle \gamma m}
+
+ were called longitudinal and transverse mass. Relativistic force does not produce a constant acceleration, but an ever-decreasing acceleration as the object approaches the speed of light. Note that 
+
+
+
+γ
+
+
+{\displaystyle \gamma }
+
+ approaches asymptotically an infinite value and is undefined for an object with a non-zero rest mass as it approaches the speed of light, and the theory yields no prediction at that speed.
+
+If 
+
+
+
+v
+
+
+{\displaystyle v}
+
+ is very small compared to 
+
+
+
+c
+
+
+{\displaystyle c}
+
+, then 
+
+
+
+γ
+
+
+{\displaystyle \gamma }
+
+ is very close to 1 and
+
+is a close approximation. Even for use in relativity, however, one can restore the form of
+
+through the use of four-vectors. This relation is correct in relativity when 
+
+
+
+
+F
+
+μ
+
+
+
+
+{\displaystyle F^{\mu }}
+
+ is the four-force, 
+
+
+
+m
+
+
+{\displaystyle m}
+
+ is the invariant mass, and 
+
+
+
+
+A
+
+μ
+
+
+
+
+{\displaystyle A^{\mu }}
+
+ is the four-acceleration.[18]
+
+Since forces are perceived as pushes or pulls, this can provide an intuitive understanding for describing forces.[2] As with other physical concepts (e.g. temperature), the intuitive understanding of forces is quantified using precise operational definitions that are consistent with direct observations and compared to a standard measurement scale. Through experimentation, it is determined that laboratory measurements of forces are fully consistent with the conceptual definition of force offered by Newtonian mechanics.
+
+Forces act in a particular direction and have sizes dependent upon how strong the push or pull is. Because of these characteristics, forces are classified as "vector quantities". This means that forces follow a different set of mathematical rules than physical quantities that do not have direction (denoted scalar quantities). For example, when determining what happens when two forces act on the same object, it is necessary to know both the magnitude and the direction of both forces to calculate the result. If both of these pieces of information are not known for each force, the situation is ambiguous. For example, if you know that two people are pulling on the same rope with known magnitudes of force but you do not know which direction either person is pulling, it is impossible to determine what the acceleration of the rope will be. The two people could be pulling against each other as in tug of war or the two people could be pulling in the same direction. In this simple one-dimensional example, without knowing the direction of the forces it is impossible to decide whether the net force is the result of adding the two force magnitudes or subtracting one from the other. Associating forces with vectors avoids such problems.
+
+Historically, forces were first quantitatively investigated in conditions of static equilibrium where several forces canceled each other out. Such experiments demonstrate the crucial properties that forces are additive vector quantities: they have magnitude and direction.[2] When two forces act on a point particle, the resulting force, the resultant (also called the net force), can be determined by following the parallelogram rule of vector addition: the addition of two vectors represented by sides of a parallelogram, gives an equivalent resultant vector that is equal in magnitude and direction to the transversal of the parallelogram.[3][4] The magnitude of the resultant varies from the difference of the magnitudes of the two forces to their sum, depending on the angle between their lines of action. However, if the forces are acting on an extended body, their respective lines of application must also be specified in order to account for their effects on the motion of the body.
+
+Free-body diagrams can be used as a convenient way to keep track of forces acting on a system. Ideally, these diagrams are drawn with the angles and relative magnitudes of the force vectors preserved so that graphical vector addition can be done to determine the net force.[19]
+
+As well as being added, forces can also be resolved into independent components at right angles to each other. A horizontal force pointing northeast can therefore be split into two forces, one pointing north, and one pointing east. Summing these component forces using vector addition yields the original force. Resolving force vectors into components of a set of basis vectors is often a more mathematically clean way to describe forces than using magnitudes and directions.[20] This is because, for orthogonal components, the components of the vector sum are uniquely determined by the scalar addition of the components of the individual vectors. Orthogonal components are independent of each other because forces acting at ninety degrees to each other have no effect on the magnitude or direction of the other. Choosing a set of orthogonal basis vectors is often done by considering what set of basis vectors will make the mathematics most convenient. Choosing a basis vector that is in the same direction as one of the forces is desirable, since that force would then have only one non-zero component. Orthogonal force vectors can be three-dimensional with the third component being at right-angles to the other two.[3][4]
+
+Equilibrium occurs when the resultant force acting on a point particle is zero (that is, the vector sum of all forces is zero). When dealing with an extended body, it is also necessary that the net torque be zero.
+
+There are two kinds of equilibrium: static equilibrium and dynamic equilibrium.
+
+Static equilibrium was understood well before the invention of classical mechanics. Objects that are at rest have zero net force acting on them.[21]
+
+The simplest case of static equilibrium occurs when two forces are equal in magnitude but opposite in direction. For example, an object on a level surface is pulled (attracted) downward toward the center of the Earth by the force of gravity. At the same time, a force is applied by the surface that resists the downward force with equal upward force (called a normal force). The situation produces zero net force and hence no acceleration.[2]
+
+Pushing against an object that rests on a frictional surface can result in a situation where the object does not move because the applied force is opposed by static friction, generated between the object and the table surface. For a situation with no movement, the static friction force exactly balances the applied force resulting in no acceleration. The static friction increases or decreases in response to the applied force up to an upper limit determined by the characteristics of the contact between the surface and the object.[2]
+
+A static equilibrium between two forces is the most usual way of measuring forces, using simple devices such as weighing scales and spring balances. For example, an object suspended on a vertical spring scale experiences the force of gravity acting on the object balanced by a force applied by the "spring reaction force", which equals the object's weight. Using such tools, some quantitative force laws were discovered: that the force of gravity is proportional to volume for objects of constant density (widely exploited for millennia to define standard weights); Archimedes' principle for buoyancy; Archimedes' analysis of the lever; Boyle's law for gas pressure; and Hooke's law for springs. These were all formulated and experimentally verified before Isaac Newton expounded his Three Laws of Motion.[2][3][4]
+
+Dynamic equilibrium was first described by Galileo who noticed that certain assumptions of Aristotelian physics were contradicted by observations and logic. Galileo realized that simple velocity addition demands that the concept of an "absolute rest frame" did not exist. Galileo concluded that motion in a constant velocity was completely equivalent to rest. This was contrary to Aristotle's notion of a "natural state" of rest that objects with mass naturally approached. Simple experiments showed that Galileo's understanding of the equivalence of constant velocity and rest were correct. For example, if a mariner dropped a cannonball from the crow's nest of a ship moving at a constant velocity, Aristotelian physics would have the cannonball fall straight down while the ship moved beneath it. Thus, in an Aristotelian universe, the falling cannonball would land behind the foot of the mast of a moving ship. However, when this experiment is actually conducted, the cannonball always falls at the foot of the mast, as if the cannonball knows to travel with the ship despite being separated from it. Since there is no forward horizontal force being applied on the cannonball as it falls, the only conclusion left is that the cannonball continues to move with the same velocity as the boat as it falls. Thus, no force is required to keep the cannonball moving at the constant forward velocity.[8]
+
+Moreover, any object traveling at a constant velocity must be subject to zero net force (resultant force). This is the definition of dynamic equilibrium: when all the forces on an object balance but it still moves at a constant velocity.
+
+A simple case of dynamic equilibrium occurs in constant velocity motion across a surface with kinetic friction. In such a situation, a force is applied in the direction of motion while the kinetic friction force exactly opposes the applied force. This results in zero net force, but since the object started with a non-zero velocity, it continues to move with a non-zero velocity. Aristotle misinterpreted this motion as being caused by the applied force. However, when kinetic friction is taken into consideration it is clear that there is no net force causing constant velocity motion.[3][4]
+
+The notion "force" keeps its meaning in quantum mechanics, though one is now dealing with operators  instead of classical variables and though the physics is now described by the Schrödinger equation instead of Newtonian equations. This has the consequence that the results of a measurement are now sometimes "quantized", i.e. they appear in discrete portions. This is, of course, difficult to imagine in the context of "forces". However, the potentials V(x,y,z) or fields, from which the forces generally can be derived, are treated similarly to classical position variables, i.e., 
+
+
+
+V
+(
+x
+,
+y
+,
+z
+)
+→
+
+
+
+V
+^
+
+
+
+(
+
+
+
+x
+^
+
+
+
+,
+
+
+
+y
+^
+
+
+
+,
+
+
+
+z
+^
+
+
+
+)
+
+
+{\displaystyle V(x,y,z)\to {\hat {V}}({\hat {x}},{\hat {y}},{\hat {z}})}
+
+.
+
+This becomes different only in the framework of quantum field theory, where these fields are also quantized.
+
+However, already in quantum mechanics there is one "caveat", namely the particles acting onto each other do not only possess the spatial variable, but also a discrete  intrinsic angular momentum-like variable called the "spin", and there is the Pauli exclusion principle relating the space and the spin variables. Depending on the value of the spin, identical particles split into two different classes, fermions and bosons.  If two identical fermions (e.g. electrons) have a symmetric spin function (e.g.  parallel spins) the spatial variables must be antisymmetric (i.e. they exclude each other from their places much as if there was a repulsive force), and vice versa, i.e. for antiparallel spins the position variables must be symmetric (i.e. the apparent force must be attractive). Thus in the case of two fermions there is a strictly negative correlation between spatial and spin variables, whereas for two bosons (e.g. quanta of electromagnetic waves, photons) the correlation is strictly positive.
+
+Thus the notion "force" loses already part of its meaning.
+
+In modern particle physics, forces and the acceleration of particles are explained as a mathematical by-product of exchange of momentum-carrying gauge bosons. With the development of quantum field theory and general relativity, it was realized that force is a redundant concept arising from conservation of momentum (4-momentum in relativity and momentum of virtual particles in quantum electrodynamics). The conservation of momentum can be directly derived from the homogeneity or symmetry of space and so is usually considered more fundamental than the concept of a force. Thus the currently known fundamental forces are considered more accurately to be "fundamental interactions".[5]:199–128 When particle A emits (creates) or absorbs (annihilates) virtual particle B, a momentum conservation results in recoil of particle A making impression of repulsion or attraction between particles A A' exchanging by B. This description applies to all forces arising from fundamental interactions. While sophisticated mathematical descriptions are needed to predict, in full detail, the accurate result of such interactions, there is a conceptually simple way to describe such interactions through the use of Feynman diagrams. In a Feynman diagram, each matter particle is represented as a straight line (see world line) traveling through time, which normally increases up or to the right in the diagram. Matter and anti-matter particles are identical except for their direction of propagation through the Feynman diagram. World lines of particles intersect at interaction vertices, and the Feynman diagram represents any force arising from an interaction as occurring at the vertex with an associated instantaneous change in the direction of the particle world lines. Gauge bosons are emitted away from the vertex as wavy lines and, in the case of virtual particle exchange, are absorbed at an adjacent vertex.[22]
+
+The utility of Feynman diagrams is that other types of physical phenomena that are part of the general picture of fundamental interactions but are conceptually separate from forces can also be described using the same rules. For example, a Feynman diagram can describe in succinct detail how a neutron decays into an electron, proton, and neutrino, an interaction mediated by the same gauge boson that is responsible for the weak nuclear force.[22]
+
+All of the known forces of the universe are classified into four fundamental interactions. The strong and the weak forces are nuclear forces that act only at very short distances, and are responsible for the interactions between subatomic particles, including nucleons and compound nuclei. The electromagnetic force acts between electric charges, and the gravitational force acts between masses. All other forces in nature derive from these four fundamental interactions. For example, friction is a manifestation of the electromagnetic force acting between atoms of two surfaces, and the Pauli exclusion principle,[23] which does not permit atoms to pass through each other. Similarly, the forces in springs, modeled by Hooke's law, are the result of electromagnetic forces and the Pauli exclusion principle acting together to return an object to its equilibrium position. Centrifugal forces are acceleration forces that arise simply from the acceleration of rotating frames of reference.[3]:12–11[4]:359
+
+The fundamental theories for forces developed from the unification of different ideas. For example, Sir. Isaac Newton unified, with his universal theory of gravitation, the force responsible for objects falling near the surface of the Earth with the force responsible for the falling of celestial bodies about the Earth (the Moon) and around the Sun (the planets). Michael Faraday and James Clerk Maxwell demonstrated that electric and magnetic forces were unified through a theory of electromagnetism. In the 20th century, the development of quantum mechanics led to a modern understanding that the first three fundamental forces (all except gravity) are manifestations of matter (fermions) interacting by exchanging virtual particles called gauge bosons.[24] This Standard Model of particle physics assumes a similarity between the forces and led scientists to predict the unification of the weak and electromagnetic forces in electroweak theory, which was subsequently confirmed by observation. The complete formulation of the Standard Model predicts an as yet unobserved Higgs mechanism, but observations such as neutrino oscillations suggest that the Standard Model is incomplete. A Grand Unified Theory that allows for the combination of the electroweak interaction with the strong force is held out as a possibility with candidate theories such as supersymmetry proposed to accommodate some of the outstanding unsolved problems in physics. Physicists are still attempting to develop self-consistent unification models that would combine all four fundamental interactions into a theory of everything. Einstein tried and failed at this endeavor, but currently the most popular approach to answering this question is string theory.[5]:212–219
+
+What we now call gravity was not identified as a universal force until the work of Isaac Newton. Before Newton, the tendency for objects to fall towards the Earth was not understood to be related to the motions of celestial objects. Galileo was instrumental in describing the characteristics of falling objects by determining that the acceleration of every object in free-fall was constant and independent of the mass of the object. Today, this acceleration due to gravity towards the surface of the Earth is usually designated as 
+
+
+
+
+
+
+
+g
+→
+
+
+
+
+
+
+{\displaystyle \scriptstyle {\vec {g}}}
+
+ and has a magnitude of about 9.81 meters per second squared (this measurement is taken from sea level and may vary depending on location), and points toward the center of the Earth.[26] This observation means that the force of gravity on an object at the Earth's surface is directly proportional to the object's mass. Thus an object that has a mass of 
+
+
+
+m
+
+
+{\displaystyle m}
+
+ will experience a force:
+
+For an object in free-fall, this force is unopposed and the net force on the object is its weight. For objects not in free-fall, the force of gravity is opposed by the reaction forces applied by their supports. For example, a person standing on the ground experiences zero net force, since a normal force (a reaction force) is exerted by the ground upward on the person that counterbalances his weight that is directed downward.[3][4]
+
+Newton's contribution to gravitational theory was to unify the motions of heavenly bodies, which Aristotle had assumed were in a natural state of constant motion, with falling motion observed on the Earth. He proposed a law of gravity that could account for the celestial motions that had been described earlier using Kepler's laws of planetary motion.[27]
+
+Newton came to realize that the effects of gravity might be observed in different ways at larger distances. In particular, Newton determined that the acceleration of the Moon around the Earth could be ascribed to the same force of gravity if the acceleration due to gravity decreased as an inverse square law. Further, Newton realized that the acceleration of a body due to gravity is proportional to the mass of the other attracting body.[27] Combining these ideas gives a formula that relates the mass (
+
+
+
+
+
+m
+
+⊕
+
+
+
+
+
+{\displaystyle \scriptstyle m_{\oplus }}
+
+) and the radius (
+
+
+
+
+
+R
+
+⊕
+
+
+
+
+
+{\displaystyle \scriptstyle R_{\oplus }}
+
+) of the Earth to the gravitational acceleration:
+
+where the vector direction is given by 
+
+
+
+
+
+
+r
+^
+
+
+
+
+
+{\displaystyle {\hat {r}}}
+
+, is the unit vector directed outward from the center of the Earth.[9]
+
+In this equation, a dimensional constant 
+
+
+
+G
+
+
+{\displaystyle G}
+
+ is used to describe the relative strength of gravity. This constant has come to be known as Newton's Universal Gravitation Constant,[28] though its value was unknown in Newton's lifetime. Not until 1798 was Henry Cavendish able to make the first measurement of 
+
+
+
+G
+
+
+{\displaystyle G}
+
+ using a torsion balance; this was widely reported in the press as a measurement of the mass of the Earth since knowing 
+
+
+
+G
+
+
+{\displaystyle G}
+
+ could allow one to solve for the Earth's mass given the above equation. Newton, however, realized that since all celestial bodies followed the same laws of motion, his law of gravity had to be universal. Succinctly stated, Newton's Law of Gravitation states that the force on a spherical object of mass 
+
+
+
+
+m
+
+1
+
+
+
+
+{\displaystyle m_{1}}
+
+ due to the gravitational pull of mass 
+
+
+
+
+m
+
+2
+
+
+
+
+{\displaystyle m_{2}}
+
+ is
+
+where 
+
+
+
+r
+
+
+{\displaystyle r}
+
+ is the distance between the two objects' centers of mass and 
+
+
+
+
+
+
+
+r
+^
+
+
+
+
+
+
+{\displaystyle \scriptstyle {\hat {r}}}
+
+ is the unit vector pointed in the direction away from the center of the first object toward the center of the second object.[9]
+
+This formula was powerful enough to stand as the basis for all subsequent descriptions of motion within the solar system until the 20th century. During that time, sophisticated methods of perturbation analysis[29] were invented to calculate the deviations of orbits due to the influence of multiple bodies on a planet, moon, comet, or asteroid. The formalism was exact enough to allow mathematicians to predict the existence of the planet Neptune before it was observed.[30]
+
+Mercury's orbit, however, did not match that predicted by Newton's Law of Gravitation. Some astrophysicists predicted the existence of another planet (Vulcan) that would explain the discrepancies; however no such planet could be found. When Albert Einstein formulated his theory of general relativity (GR) he turned his attention to the problem of Mercury's orbit and found that his theory added a correction, which could account for the discrepancy. This was the first time that Newton's Theory of Gravity had been shown to be inexact.[32]
+
+Since then, general relativity has been acknowledged as the theory that best explains gravity. In GR, gravitation is not viewed as a force, but rather, objects moving freely in gravitational fields travel under their own inertia in straight lines through curved space-time – defined as the shortest space-time path between two space-time events. From the perspective of the object, all motion occurs as if there were no gravitation whatsoever. It is only when observing the motion in a global sense that the curvature of space-time can be observed and the force is inferred from the object's curved path. Thus, the straight line path in space-time is seen as a curved line in space, and it is called the ballistic trajectory of the object. For example, a basketball thrown from the ground moves in a parabola, as it is in a uniform gravitational field. Its space-time trajectory is almost a straight line, slightly curved (with the radius of curvature of the order of few light-years). The time derivative of the changing momentum of the object is what we label as "gravitational force".[4]
+
+The electrostatic force was first described in 1784 by Coulomb as a force that existed intrinsically between two charges.[16]:519 The properties of the electrostatic force were that it varied as an inverse square law directed in the radial direction, was both attractive and repulsive (there was intrinsic polarity), was independent of the mass of the charged objects, and followed the superposition principle. Coulomb's law unifies all these observations into one succinct statement.[33]
+
+Subsequent mathematicians and physicists found the construct of the electric field to be useful for determining the electrostatic force on an electric charge at any point in space. The electric field was based on using a hypothetical "test charge" anywhere in space and then using Coulomb's Law to determine the electrostatic force.[34]:4–6 to 4–8 Thus the electric field anywhere in space is defined as
+
+where 
+
+
+
+q
+
+
+{\displaystyle q}
+
+ is the magnitude of the hypothetical test charge.
+
+Meanwhile, the Lorentz force of magnetism was discovered to exist between two electric currents. It has the same mathematical character as Coulomb's Law with the proviso that like currents attract and unlike currents repel. Similar to the electric field, the magnetic field can be used to determine the magnetic force on an electric current at any point in space. In this case, the magnitude of the magnetic field was determined to be
+
+where 
+
+
+
+I
+
+
+{\displaystyle I}
+
+ is the magnitude of the hypothetical test current and 
+
+
+
+
+ℓ
+
+
+
+{\displaystyle \scriptstyle \ell }
+
+ is the length of hypothetical wire through which the test current flows. The magnetic field exerts a force on all magnets including, for example, those used in compasses. The fact that the Earth's magnetic field is aligned closely with the orientation of the Earth's axis causes compass magnets to become oriented because of the magnetic force pulling on the needle.
+
+Through combining the definition of electric current as the time rate of change of electric charge, a rule of vector multiplication called Lorentz's Law describes the force on a charge moving in a magnetic field.[34] The connection between electricity and magnetism allows for the description of a unified electromagnetic force that acts on a charge. This force can be written as a sum of the electrostatic force (due to the electric field) and the magnetic force (due to the magnetic field). Fully stated, this is the law:
+
+where 
+
+
+
+
+
+
+
+F
+→
+
+
+
+
+
+
+{\displaystyle \scriptstyle {\vec {F}}}
+
+ is the electromagnetic force, 
+
+
+
+q
+
+
+{\displaystyle q}
+
+ is the magnitude of the charge of the particle, 
+
+
+
+
+
+
+
+E
+→
+
+
+
+
+
+
+{\displaystyle \scriptstyle {\vec {E}}}
+
+ is the electric field, 
+
+
+
+
+
+
+
+v
+→
+
+
+
+
+
+
+{\displaystyle \scriptstyle {\vec {v}}}
+
+ is the velocity of the particle that is crossed with the magnetic field (
+
+
+
+
+
+
+
+B
+→
+
+
+
+
+
+
+{\displaystyle \scriptstyle {\vec {B}}}
+
+).
+
+The origin of electric and magnetic fields would not be fully explained until 1864 when James Clerk Maxwell unified a number of earlier theories into a set of 20 scalar equations, which were later reformulated into 4 vector equations by Oliver Heaviside and Josiah Willard Gibbs.[35] These "Maxwell Equations" fully described the sources of the fields as being stationary and moving charges, and the interactions of the fields themselves. This led Maxwell to discover that electric and magnetic fields could be "self-generating" through a wave that traveled at a speed that he calculated to be the speed of light. This insight united the nascent fields of electromagnetic theory with optics and led directly to a complete description of the electromagnetic spectrum.[36]
+
+However, attempting to reconcile electromagnetic theory with two observations, the photoelectric effect, and the nonexistence of the ultraviolet catastrophe, proved troublesome. Through the work of leading theoretical physicists, a new theory of electromagnetism was developed using quantum mechanics. This final modification to electromagnetic theory ultimately led to quantum electrodynamics (or QED), which fully describes all electromagnetic phenomena as being mediated by wave–particles known as photons. In QED, photons are the fundamental exchange particle, which described all interactions relating to electromagnetism including the electromagnetic force.[Note 4]
+
+There are two "nuclear forces", which today are usually described as interactions that take place in quantum theories of particle physics. The strong nuclear force[16]:940 is the force responsible for the structural integrity of atomic nuclei while the weak nuclear force[16]:951 is responsible for the decay of certain nucleons into leptons and other types of hadrons.[3][4]
+
+The strong force is today understood to represent the interactions between quarks and gluons as detailed by the theory of quantum chromodynamics (QCD).[37] The strong force is the fundamental force mediated by gluons, acting upon quarks, antiquarks, and the gluons themselves. The (aptly named) strong interaction is the "strongest" of the four fundamental forces.
+
+The strong force only acts directly upon elementary particles. However, a residual of the force is observed between hadrons (the best known example being the force that acts between nucleons in atomic nuclei) as the nuclear force. Here the strong force acts indirectly, transmitted as gluons, which form part of the virtual pi and rho mesons, which classically transmit the nuclear force (see this topic for more). The failure of many searches for free quarks has shown that the elementary particles affected are not directly observable. This phenomenon is called color confinement.
+
+The weak force is due to the exchange of the heavy W and Z bosons. Its most familiar effect is beta decay (of neutrons in atomic nuclei) and the associated radioactivity. The word "weak" derives from the fact that the field strength is some 1013 times less than that of the strong force. Still, it is stronger than gravity over short distances. A consistent electroweak theory has also been developed, which shows that electromagnetic forces and the weak force are indistinguishable at a temperatures in excess of approximately 1015 kelvins. Such temperatures have been probed in modern particle accelerators and show the conditions of the universe in the early moments of the Big Bang.
+
+Some forces are consequences of the fundamental ones. In such situations, idealized models can be utilized to gain physical insight.
+
+The normal force is due to repulsive forces of interaction between atoms at close contact. When their electron clouds overlap, Pauli repulsion (due to fermionic nature of electrons) follows resulting in the force that acts in a direction normal to the surface interface between two objects.[16]:93 The normal force, for example, is responsible for the structural integrity of tables and floors as well as being the force that responds whenever an external force pushes on a solid object. An example of the normal force in action is the impact force on an object crashing into an immobile surface.[3][4]
+
+Friction is a surface force that opposes relative motion. The frictional force is directly related to the normal force that acts to keep two solid objects separated at the point of contact. There are two broad classifications of frictional forces: static friction and kinetic friction.
+
+The static friction force (
+
+
+
+
+F
+
+
+s
+f
+
+
+
+
+
+{\displaystyle F_{\mathrm {sf} }}
+
+) will exactly oppose forces applied to an object parallel to a surface contact up to the limit specified by the coefficient of static friction (
+
+
+
+
+μ
+
+
+s
+f
+
+
+
+
+
+{\displaystyle \mu _{\mathrm {sf} }}
+
+) multiplied by the normal force (
+
+
+
+
+F
+
+N
+
+
+
+
+{\displaystyle F_{N}}
+
+). In other words, the magnitude of the static friction force satisfies the inequality:
+
+The kinetic friction force (
+
+
+
+
+F
+
+
+k
+f
+
+
+
+
+
+{\displaystyle F_{\mathrm {kf} }}
+
+) is independent of both the forces applied and the movement of the object. Thus, the magnitude of the force equals:
+
+where 
+
+
+
+
+μ
+
+
+k
+f
+
+
+
+
+
+{\displaystyle \mu _{\mathrm {kf} }}
+
+ is the coefficient of kinetic friction. For most surface interfaces, the coefficient of kinetic friction is less than the coefficient of static friction.
+
+Tension forces can be modeled using ideal strings that are massless, frictionless, unbreakable, and unstretchable. They can be combined with ideal pulleys, which allow ideal strings to switch physical direction. Ideal strings transmit tension forces instantaneously in action-reaction pairs so that if two objects are connected by an ideal string, any force directed along the string by the first object is accompanied by a force directed along the string in the opposite direction by the second object.[38] By connecting the same string multiple times to the same object through the use of a set-up that uses movable pulleys, the tension force on a load can be multiplied. For every string that acts on a load, another factor of the tension force in the string acts on the load. However, even though such machines allow for an increase in force, there is a corresponding increase in the length of string that must be displaced in order to move the load. These tandem effects result ultimately in the conservation of mechanical energy since the work done on the load is the same no matter how complicated the machine.[3][4][39]
+
+An elastic force acts to return a spring to its natural length. An ideal spring is taken to be massless, frictionless, unbreakable, and infinitely stretchable. Such springs exert forces that push when contracted, or pull when extended, in proportion to the displacement of the spring from its equilibrium position.[40] This linear relationship was described by Robert Hooke in 1676, for whom Hooke's law is named. If 
+
+
+
+Δ
+x
+
+
+{\displaystyle \Delta x}
+
+ is the displacement, the force exerted by an ideal spring equals:
+
+where 
+
+
+
+k
+
+
+{\displaystyle k}
+
+ is the spring constant (or force constant), which is particular to the spring. The minus sign accounts for the tendency of the force to act in opposition to the applied load.[3][4]
+
+Newton's laws and Newtonian mechanics in general were first developed to describe how forces affect idealized point particles rather than three-dimensional objects. However, in real life, matter has extended structure and forces that act on one part of an object might affect other parts of an object. For situations where lattice holding together the atoms in an object is able to flow, contract, expand, or otherwise change shape, the theories of continuum mechanics describe the way forces affect the material. For example, in extended fluids, differences in pressure result in forces being directed along the pressure gradients as follows:
+
+where 
+
+
+
+V
+
+
+{\displaystyle V}
+
+ is the volume of the object in the fluid and 
+
+
+
+P
+
+
+{\displaystyle P}
+
+ is the scalar function that describes the pressure at all locations in space. Pressure gradients and differentials result in the buoyant force for fluids suspended in gravitational fields, winds in atmospheric science, and the lift associated with aerodynamics and flight.[3][4]
+
+A specific instance of such a force that is associated with dynamic pressure is fluid resistance: a body force that resists the motion of an object through a fluid due to viscosity. For so-called "Stokes' drag" the force is approximately proportional to the velocity, but opposite in direction:
+
+where:
+
+More formally, forces in continuum mechanics are fully described by a stress–tensor with terms that are roughly defined as
+
+where 
+
+
+
+A
+
+
+{\displaystyle A}
+
+ is the relevant cross-sectional area for the volume for which the stress-tensor is being calculated. This formalism includes pressure terms associated with forces that act normal to the cross-sectional area (the matrix diagonals of the tensor) as well as shear terms associated with forces that act parallel to the cross-sectional area (the off-diagonal elements). The stress tensor accounts for forces that cause all strains (deformations) including also tensile stresses and compressions.[2][4]:133–134[34]:38–1–38–11
+
+There are forces that are frame dependent, meaning that they appear due to the adoption of non-Newtonian (that is, non-inertial) reference frames. Such forces include the centrifugal force and the Coriolis force.[41] These forces are considered fictitious because they do not exist in frames of reference that are not accelerating.[3][4] Because these forces are not genuine they are also referred to as "pseudo forces".[3]:12–11
+
+In general relativity, gravity becomes a fictitious force that arises in situations where spacetime deviates from a flat geometry. As an extension, Kaluza–Klein theory and string theory ascribe electromagnetism and the other fundamental forces respectively to the curvature of differently scaled dimensions, which would ultimately imply that all forces are fictitious.
+
+Forces that cause extended objects to rotate are associated with torques. Mathematically, the torque of a force 
+
+
+
+
+
+
+
+F
+→
+
+
+
+
+
+
+{\displaystyle \scriptstyle {\vec {F}}}
+
+ is defined relative to an arbitrary reference point as the cross-product:
+
+where
+
+Torque is the rotation equivalent of force in the same way that angle is the rotational equivalent for position, angular velocity for velocity, and angular momentum for momentum. As a consequence of Newton's First Law of Motion, there exists rotational inertia that ensures that all bodies maintain their angular momentum unless acted upon by an unbalanced torque. Likewise, Newton's Second Law of Motion can be used to derive an analogous equation for the instantaneous angular acceleration of the rigid body:
+
+where
+
+This provides a definition for the moment of inertia, which is the rotational equivalent for mass. In more advanced treatments of mechanics, where the rotation over a time interval is described, the moment of inertia must be substituted by the tensor that, when properly analyzed, fully determines the characteristics of rotations including precession and nutation.
+
+Equivalently, the differential form of Newton's Second Law provides an alternative definition of torque:
+
+Newton's Third Law of Motion requires that all objects exerting torques themselves experience equal and opposite torques,[43] and therefore also directly implies the conservation of angular momentum for closed systems that experience rotations and revolutions through the action of internal torques.
+
+For an object accelerating in circular motion, the unbalanced force acting on the object equals:[44]
+
+where 
+
+
+
+m
+
+
+{\displaystyle m}
+
+ is the mass of the object, 
+
+
+
+v
+
+
+{\displaystyle v}
+
+ is the velocity of the object and 
+
+
+
+r
+
+
+{\displaystyle r}
+
+ is the distance to the center of the circular path and 
+
+
+
+
+
+
+
+r
+^
+
+
+
+
+
+
+{\displaystyle \scriptstyle {\hat {r}}}
+
+ is the unit vector pointing in the radial direction outwards from the center. This means that the unbalanced centripetal force felt by any object is always directed toward the center of the curving path. Such forces act perpendicular to the velocity vector associated with the motion of an object, and therefore do not change the speed of the object (magnitude of the velocity), but only the direction of the velocity vector. The unbalanced force that accelerates an object can be resolved into a component that is perpendicular to the path, and one that is tangential to the path. This yields both the tangential force, which accelerates the object by either slowing it down or speeding it up, and the radial (centripetal) force, which changes its direction.[3][4]
+
+Forces can be used to define a number of physical concepts by integrating with respect to kinematic variables. For example, integrating with respect to time gives the definition of impulse:[45]
+
+which by Newton's Second Law must be equivalent to the change in momentum (yielding the Impulse momentum theorem).
+
+Similarly, integrating with respect to position gives a definition for the work done by a force:[3]:13–3
+
+which is equivalent to changes in kinetic energy (yielding the work energy theorem).[3]:13–3
+
+Power P is the rate of change dW/dt of the work W, as the trajectory is extended by a position change 
+
+
+
+
+
+d
+
+
+
+
+x
+→
+
+
+
+
+
+
+{\displaystyle \scriptstyle {d}{\vec {x}}}
+
+ in a time interval dt:[3]:13–2
+
+with 
+
+
+
+
+
+
+
+v
+→
+
+
+
+
+ 
+
+=
+
+ d
+
+
+
+
+x
+→
+
+
+
+
+/
+
+
+d
+
+t
+
+
+
+{\displaystyle {{\vec {v}}{\text{ }}={\text{ d}}{\vec {x}}/{\text{d}}t}}
+
+ the velocity.
+
+Instead of a force, often the mathematically related concept of a potential energy field can be used for convenience. For instance, the gravitational force acting upon an object can be seen as the action of the gravitational field that is present at the object's location. Restating mathematically the definition of energy (via the definition of work), a potential scalar field 
+
+
+
+
+
+U
+(
+
+
+
+r
+→
+
+
+
+)
+
+
+
+
+{\displaystyle \scriptstyle {U({\vec {r}})}}
+
+ is defined as that field whose gradient is equal and opposite to the force produced at every point:
+
+Forces can be classified as conservative or nonconservative. Conservative forces are equivalent to the gradient of a potential while nonconservative forces are not.[3][4]
+
+A conservative force that acts on a closed system has an associated mechanical work that allows energy to convert only between kinetic or potential forms. This means that for a closed system, the net mechanical energy is conserved whenever a conservative force acts on the system. The force, therefore, is related directly to the difference in potential energy between two different locations in space,[46] and can be considered to be an artifact of the potential field in the same way that the direction and amount of a flow of water can be considered to be an artifact of the contour map of the elevation of an area.[3][4]
+
+Conservative forces include gravity, the electromagnetic force, and the spring force. Each of these forces has models that are dependent on a position often given as a radial vector 
+
+
+
+
+
+
+
+r
+→
+
+
+
+
+
+
+{\displaystyle \scriptstyle {\vec {r}}}
+
+ emanating from spherically symmetric potentials.[47] Examples of this follow:
+
+For gravity:
+
+where 
+
+
+
+G
+
+
+{\displaystyle G}
+
+ is the gravitational constant, and 
+
+
+
+
+m
+
+n
+
+
+
+
+{\displaystyle m_{n}}
+
+ is the mass of object n.
+
+For electrostatic forces:
+
+where 
+
+
+
+
+ϵ
+
+0
+
+
+
+
+{\displaystyle \epsilon _{0}}
+
+ is electric permittivity of free space, and 
+
+
+
+
+q
+
+n
+
+
+
+
+{\displaystyle q_{n}}
+
+ is the electric charge of object n.
+
+For spring forces:
+
+where 
+
+
+
+k
+
+
+{\displaystyle k}
+
+ is the spring constant.[3][4]
+
+For certain physical scenarios, it is impossible to model forces as being due to gradient of potentials. This is often due to macrophysical considerations that yield forces as arising from a macroscopic statistical average of microstates. For example, friction is caused by the gradients of numerous electrostatic potentials between the atoms, but manifests as a force model that is independent of any macroscale position vector. Nonconservative forces other than friction include other contact forces, tension, compression, and drag. However, for any sufficiently detailed description, all these forces are the results of conservative ones since each of these macroscopic forces are the net results of the gradients of microscopic potentials.[3][4]
+
+The connection between macroscopic nonconservative forces and microscopic conservative forces is described by detailed treatment with statistical mechanics. In macroscopic closed systems, nonconservative forces act to change the internal energies of the system, and are often associated with the transfer of heat. According to the Second law of thermodynamics, nonconservative forces necessarily result in energy transformations within closed systems from ordered to more random conditions as entropy increases.[3][4]
+
+The SI unit of force is the newton (symbol N), which is the force required to accelerate a one kilogram mass at a rate of one meter per second squared, or kg·m·s−2.[48] The corresponding CGS unit is the dyne, the force required to accelerate a one gram mass by one centimeter per second squared, or g·cm·s−2. A newton is thus equal to 100,000 dynes.
+
+The gravitational foot-pound-second English unit of force is the pound-force (lbf), defined as the force exerted by gravity on a pound-mass in the standard gravitational field of 9.80665 m·s−2.[48] The pound-force provides an alternative unit of mass: one slug is the mass that will accelerate by one foot per second squared when acted on by one pound-force.[48]
+
+An alternative unit of force in a different foot-pound-second system, the absolute fps system, is the poundal, defined as the force required to accelerate a one-pound mass at a rate of one foot per second squared.[48] The units of slug and poundal are designed to avoid a constant of proportionality in Newton's Second Law.
+
+The pound-force has a metric counterpart, less commonly used than the newton: the kilogram-force (kgf) (sometimes kilopond), is the force exerted by standard gravity on one kilogram of mass.[48] The kilogram-force leads to an alternate, but rarely used unit of mass: the metric slug (sometimes mug or hyl) is that mass that accelerates at 1 m·s−2 when subjected to a force of 1 kgf. The kilogram-force is not a part of the modern SI system, and is generally deprecated; however it still sees use for some purposes as expressing aircraft weight, jet thrust, bicycle spoke tension, torque wrench settings and engine output torque. Other arcane units of force include the sthène, which is equivalent to 1000 N, and the kip, which is equivalent to 1000 lbf.
+
+See also Ton-force.
+
+See force gauge, spring scale, load cell
+

en/2035.html.txt

@@ -0,0 +1,261 @@
+
+
+The police are a constituted body of persons empowered by a state, with the aim to enforce the law, to ensure the safety, health and possessions of citizens, and to prevent crime and civil disorder.[1][2] Their lawful powers include arrest and the use of force legitimized by the state via the monopoly on violence. The term is most commonly associated with the police forces of a sovereign state that are authorized to exercise the police power of that state within a defined legal or territorial area of responsibility. Police forces are often defined as being separate from the military and other organizations involved in the defense of the state against foreign aggressors; however, gendarmerie are military units charged with civil policing.[3] Police forces are usually public sector services, funded through taxes.
+
+Law enforcement is only part of policing activity.[4] Policing has included an array of activities in different situations, but the predominant ones are concerned with the preservation of order.[5] In some societies, in the late 18th and early 19th centuries, these developed within the context of maintaining the class system and the protection of private property.[6] Police forces have become ubiquitous in modern societies. Nevertheless, their role can be controversial, as some are involved to varying degrees in corruption, police brutality and the enforcement of authoritarian rule.
+
+A police force may also be referred to as a police department, police service, constabulary, gendarmerie, crime prevention, protective services, law enforcement agency, civil guard or civic guard[disambiguation needed]. Members may be referred to as police officers, troopers, sheriffs, constables, rangers, peace officers or civic/civil guards. Ireland differs from other English-speaking countries by using the Irish language terms Garda (singular) and Gardaí (plural), for both the national police force and its members. The word "police" is the most universal and similar terms can be seen in many non-English speaking countries.[7]
+
+Numerous slang terms exist for the police. Many slang terms for police officers are decades or centuries old with lost etymology. One of the oldest, "cop", has largely lost its slang connotations and become a common colloquial term used both by the public and police officers to refer to their profession.[8]
+
+First attested in English in the early 15th century, initially in a range of senses encompassing '(public) policy; state; public order', the word police comes from Middle French police ('public order, administration, government'),[9] in turn from Latin politia,[10] which is the Latinisation of the Greek πολιτεία (politeia), "citizenship, administration, civil polity".[11] This is derived from πόλις (polis), "city".[12]
+
+Law enforcement in ancient China was carried out by "prefects" for thousands of years since it developed in both the Chu and Jin kingdoms of the Spring and Autumn period. In Jin, dozens of prefects were spread across the state, each having limited authority and employment period. They were appointed by local magistrates, who reported to higher authorities such as governors, who in turn were appointed by the emperor, and they oversaw the civil administration of their "prefecture", or jurisdiction. Under each prefect were "subprefects" who helped collectively with law enforcement in the area. Some prefects were responsible for handling investigations, much like modern police detectives. Prefects could also be women.[13] Local citizens could report minor judicial offenses against them such as robberies at a local prefectural office. The concept of the "prefecture system" spread to other cultures such as Korea and Japan.
+
+In Babylonia, law enforcement tasks were initially entrusted to individuals with military backgrounds or imperial magnates during the Old Babylonian period, but eventually, law enforcement was delegated to officers known as paqūdus, who were present in both cities and rural settlements. A paqūdu was responsible for investigating petty crimes and carrying out arrests.[14][15]
+
+In ancient Egypt evidence of law enforcement exists as far back as the Old Kingdom period. There are records of an office known as "Judge Commandant of the Police" dating to the fourth dynasty.[16] During the fifth dynasty at the end of the Old Kingdom period, officers armed with wooden sticks were tasked with guarding public places such as markets, temples,  and parks,  and apprehending criminals. They are known to have made use of trained monkeys, baboons, and dogs in guard duties and catching criminals. After the Old Kingdom collapsed, ushering in the First Intermediate Period, it is thought that the same model applied. During this period, Bedouins were hired to guard the borders and protect trade caravans.  During the Middle Kingdom period, a professional police force was created with a specific focus on enforcing the law, as opposed to the previous informal arrangement of using warriors as police. The police force was further reformed during the New Kingdom period. Police officers served as interrogators, prosecutors, and court bailiffs, and were responsible for administering punishments handed down by judges. In addition, there were special units of police officers trained as priests who were responsible for guarding temples and tombs and preventing inappropriate behavior at festivals or improper observation of religious rites during services. Other police units were tasked with guarding caravans, guarding border crossings, protecting royal necropolises, guarding slaves at work or during transport, patrolling the Nile River, and guarding administrative buildings. The police did not guard rural communities, which often took care of their own judicial problems by appealing to village elders, but many of them had a constable to enforce state laws.[17]
+
+In ancient Greece, publicly owned slaves were used by magistrates as police. In Athens, a group of 300 Scythian slaves (the ῥαβδοῦχοι, "rod-bearers") was used to guard public meetings to keep order and for crowd control, and also assisted with dealing with criminals, handling prisoners, and making arrests. Other duties associated with modern policing, such as investigating crimes, were left to the citizens themselves.[18] In Sparta, a secret police force called the krypteia existed to watch the large population of helots, or slaves.[19]
+
+In the Roman Empire, the army, rather than a dedicated police organization, initially provided security. Local watchmen were hired by cities to provide some extra security. Magistrates such as procurators fiscal and quaestors investigated crimes. There was no concept of public prosecution, so victims of crime or their families had to organize and manage the prosecution themselves. Under the reign of Augustus, when the capital had grown to almost one million inhabitants, 14 wards were created; the wards were protected by seven squads of 1,000 men called "vigiles", who acted as firemen and nightwatchmen. Their duties included apprehending thieves and robbers, capturing runaway slaves, guarding the baths at night, and stopping disturbances of the peace. The vigiles primarily dealt with petty crime, while violent crime,  sedition,  and rioting was handled by the Urban Cohorts and even the Praetorian Guard if necessary, though the vigiles could act in a supporting role in these situations.
+
+Law enforcement systems existed in the various kingdoms and empires of ancient India. The Apastamba Dharmasutra prescribes that kings should appoint officers and subordinates in the towns and villages to protect their subjects from crime. Various inscriptions and literature from ancient India suggest that a variety of roles existed for law enforcement officials such as  those of a constable, thief catcher, watchman, and detective.[20]
+
+The Persian Empire had well-organized police forces. A police force existed in every place of importance. In the cities, each ward was under the command of a Superintendent of Police, known as a Kuipan, who was expected to command implicit obedience in his subordinates. Police officers also acted as prosecutors and carried out punishments imposed by the courts. They were required to know the court procedure for prosecuting cases and advancing accusations.[21]
+
+In ancient Israel and Judah, officials with the responsibility of making declarations to the people, guarding the king's person, supervising public works, and executing the orders of the courts existed in the urban areas. They are repeatedly mentioned in the Hebrew Bible, and this system lasted into the period of Roman rule. The first century Jewish historian Josephus related that every judge had two such officers under his command. Levites were preferred for this role. Cities and towns also had night watchmen. Besides officers of the town,  there were officers for every tribe. The temple in Jerusalem had special temple police to guard it. The Talmud also mentions various local police officials in the Jewish communities the Land of Israel and Babylon who supervised economic activity. Their Greek-sounding titles suggest that the roles were introduced under Hellenic influence. Most of these officials received their authority from local courts and their salaries were drawn from the town treasury. The Talmud also mentions city watchmen and mounted and armed watchmen in the suburbs.[22]
+
+In many regions of pre-colonial Africa, particularly West and Central Africa, guild-like secret societies emerged as law enforcement. In the absence of a court system or written legal code, they carried out police-like activities, employing varying degrees of coercion to enforce conformity and deter antisocial behavior.[23] In ancient Ethiopia, armed retainers of the nobility enforced law in the countryside according to the will of their leaders. The Songhai Empire had officials known as assara-munidios, or "enforcers", acting as police.
+
+Pre-Colombian Mesoamarican civilizations also had organized law enforcement. The city-states of the Maya civilization had constables known as tupils, as well as bailiffs.[24] In the Aztec Empire, judges had officers serving under them who were empowered to perform arrests, even of dignitaries.[25] In the Inca Empire, officials called curaca enforced the law among the households they were assigned to oversee, with inspectors known as tokoyrikoq (lit. "he who sees all") also stationed throughout the provinces to keep order.[26][27]
+
+In medieval Spain, Santas Hermandades, or "holy brotherhoods", peacekeeping associations of armed individuals, were a characteristic of municipal life, especially in Castile. As medieval Spanish kings often could not offer adequate protection, protective municipal leagues began to emerge in the twelfth century against banditry and other rural criminals, and against the lawless nobility or to support one or another claimant to a crown.
+
+These organizations were intended to be temporary, but became a long-standing fixture of Spain. The first recorded case of the formation of an hermandad occurred when the towns and the peasantry of the north united to police the pilgrim road to Santiago de Compostela in Galicia, and protect the pilgrims against robber knights.
+
+Throughout the Middle Ages such alliances were frequently formed by combinations of towns to protect the roads connecting them, and were occasionally extended to political purposes. Among the most powerful was the league of North Castilian and Basque ports, the Hermandad de las marismas: Toledo, Talavera, and Villarreal.
+
+As one of their first acts after end of the War of the Castilian Succession in 1479, Ferdinand II of Aragon and Isabella I of Castile established the centrally-organized and efficient Holy Brotherhood as a national police force. They adapted an existing brotherhood to the purpose of a general police acting under officials appointed by themselves, and endowed with great powers of summary jurisdiction even in capital cases. The original brotherhoods continued to serve as modest local police-units until their final suppression in 1835.
+
+The Vehmic courts of Germany provided some policing in the absence of strong state institutions. Such courts had a chairman who presided over a session and lay judges who passed judgement and carried out law enforcement tasks. Among the responsibilities that lay judges had were giving formal warnings to known troublemakers, issuing warrants, and carrying out executions.
+
+In the medieval Islamic Caliphates, police were known as Shurta. Bodies termed "Shurta" existed perhaps as early as the Caliphate of Uthman. It is known in the Abbasid and Umayyad Caliphates. Their primary roles were to act as police and internal security forces but could also be used for other duties such as customs and tax enforcement, rubbish collection, and acting as bodyguards for governors. From the 10th century, the importance of the Shurta declined as the army assumed internal security tasks while cities became more autonomous and handled their own policing needs locally, such as by hiring watchmen. In addition, officials called muhtasibs were responsible for supervising bazaars and economic activity in general in the medieval Islamic world.
+
+In France during the Middle Ages, there were two Great Officers of the Crown of France with police responsibilities: The Marshal of France and the Grand Constable of France. The military policing responsibilities of the Marshal of France were delegated to the Marshal's provost, whose force was known as the Marshalcy because its authority ultimately derived from the Marshal. The marshalcy dates back to the Hundred Years' War, and some historians trace it back to the early 12th century. Another organisation, the Constabulary (French: Connétablie), was under the command of the Constable of France. The constabulary was regularised as a military body in 1337. Under Francis I of France (who reigned 1515–1547), the Maréchaussée was merged with the Constabulary. The resulting force was also known as the Maréchaussée, or, formally, the Constabulary and Marshalcy of France.
+
+The English system of maintaining public order since the Norman conquest was a private system of tithings known as the mutual pledge system. This system was introduced under Alfred the Great. Communities were divided into groups of ten families called tithings, each of which was overseen by a chief tithingman. Every household head was responsible for the good behavior of his own family and the good behavior of other members of his tithing. Every male aged 12 and over was required to participate in a tithing. Members of tithings were responsible for raising "hue and cry" upon witnessing or learning of a crime, and the men of his tithing were responsible for capturing the criminal. The person the tithing captured would then be brought before the chief tithingman, who would determine guilt or innocence and punishment. All members of the criminal's tithing would be responsible for paying the fine. A group of ten tithings was known as a "hundred" and every hundred was overseen by an official known as a reeve. Hundreds ensured that if a criminal escaped to a neighboring village, he could be captured and returned to his village. If a criminal was not apprehended, then the entire hundred could be fined. The hundreds were governed by administrative divisions known as shires, the rough equivalent of a modern county, which were overseen by an official known as a shire-reeve, from which the term Sheriff evolved. The shire-reeve had the power of posse comitatus, meaning he could gather the men of his shire to pursue a criminal.[28] Following the Norman conquest of England in 1066, the tithing system was tightened with the frankpledge system. By the end of the 13th century, the office of constable developed. Constables had the same responsibilities as chief tithingmen and additionally as royal officers. The constable was elected by his parish every year. Eventually, constables became the first 'police' official to be tax-supported. In urban areas, watchmen were tasked with keeping order and enforcing nighttime curfew. Watchmen guarded the town gates at night, patrolled the streets, arrested those on the streets at night without good reason, and also acted as firefighters. Eventually the office of justice of the peace was established, with a justice of the peace overseeing constables.[29][30] There was also a system of investigative "juries".
+
+The Assize of Arms of 1252, which required the appointment of constables to summon men to arms, quell breaches of the peace, and to deliver offenders to the sheriff or reeve, is cited as one of the earliest antecedents of the English police.[31] The Statute of Winchester of 1285 is also cited as the primary legislation regulating the policing of the country between the Norman Conquest and the Metropolitan Police Act 1829.[31][32]
+
+From about 1500, private watchmen were funded by private individuals and organisations to carry out police functions. They were later nicknamed 'Charlies', probably after the reigning monarch King Charles II. Thief-takers were also rewarded for catching thieves and returning the stolen property.
+
+The earliest English use of the word "police" seems to have been the term "Polles" mentioned in the book "The Second Part of the Institutes of the Lawes of England" published in 1642.[33]
+
+The first centrally organised and uniformed police force was created by the government of King Louis XIV in 1667 to police the city of Paris, then the largest city in Europe. The royal edict, registered by the Parlement of Paris on March 15, 1667 created the office of lieutenant général de police ("lieutenant general of police"), who was to be the head of the new Paris police force, and defined the task of the police as "ensuring the peace and quiet of the public and of private individuals, purging the city of what may cause disturbances, procuring abundance, and having each and everyone live according to their station and their duties".
+
+This office was first held by Gabriel Nicolas de la Reynie, who had 44 commissaires de police (police commissioners) under his authority. In 1709, these commissioners were assisted by inspecteurs de police (police inspectors). The city of Paris was divided into 16 districts policed by the commissaires, each assigned to a particular district and assisted by a growing bureaucracy. The scheme of the Paris police force was extended to the rest of France by a royal edict of October 1699, resulting in the creation of lieutenants general of police in all large French cities and towns.
+
+After the French Revolution, Napoléon I reorganized the police in Paris and other cities with more than 5,000 inhabitants on February 17, 1800 as the Prefecture of Police. On March 12, 1829, a government decree created the first uniformed police in France, known as sergents de ville ("city sergeants"), which the Paris Prefecture of Police's website claims were the first uniformed policemen in the world.[34]
+
+In 1737, George II began paying some London and Middlesex watchmen with tax monies, beginning the shift to government control. In 1749 Henry Fielding began organizing a force of quasi-professional constables known as the Bow Street Runners. The Macdaniel affair added further impetus for a publicly salaried police force that did not depend on rewards. Nonetheless, In 1828, there were privately financed police units in no fewer than 45 parishes within a 10-mile radius of London.
+
+The word "police" was borrowed from French into the English language in the 18th century, but for a long time it applied only to French and continental European police forces. The word, and the concept of police itself, were "disliked as a symbol of foreign oppression" (according to Britannica 1911). Before the 19th century, the first use of the word "police" recorded in government documents in the United Kingdom was the appointment of Commissioners of Police for Scotland in 1714 and the creation of the Marine Police in 1798.
+
+Following early police forces established in 1779 and 1788 in Glasgow, Scotland, the Glasgow authorities successfully petitioned the government to pass the Glasgow Police Act establishing the City of Glasgow Police in 1800.[35] Other Scottish towns soon followed suit and set up their own police forces through acts of parliament.[36] In Ireland, the Irish Constabulary Act of 1822 marked the beginning of the Royal Irish Constabulary. The Act established a force in each barony with chief constables and inspectors general under the control of the civil administration at Dublin Castle. By 1841 this force numbered over 8,600 men.
+
+In 1797, Patrick Colquhoun was able to persuade the West Indies merchants who operated at the Pool of London on the River Thames, to establish a police force at the docks to prevent rampant theft that was causing annual estimated losses of £500,000 worth of cargo.[37] The idea of a police, as it then existed in France, was considered as a potentially undesirable foreign import. In building the case for the police in the face of England's firm anti-police sentiment, Colquhoun framed the political rationale on economic indicators to show that a police dedicated to crime prevention was "perfectly congenial to the principle of the British constitution". Moreover, he went so far as to praise the French system, which had reached "the greatest degree of perfection" in his estimation.[38]
+
+With the initial investment of £4,200, the new trial force of the Thames River Police began with about 50 men charged with policing 33,000 workers in the river trades, of whom Colquhoun claimed 11,000 were known criminals and "on the game". The force was a success after its first year, and his men had "established their worth by saving £122,000 worth of cargo and by the rescuing of several lives". Word of this success spread quickly, and the government passed the Marine Police Bill on 28 July 1800, transforming it from a private to public police agency; now the oldest police force in the world. Colquhoun published a book on the experiment, The Commerce and Policing of the River Thames. It found receptive audiences far outside London, and inspired similar forces in other cities, notably, New York City, Dublin, and Sydney.[37]
+
+Colquhoun's utilitarian approach to the problem – using a cost-benefit argument to obtain support from businesses standing to benefit – allowed him to achieve what Henry and John Fielding failed for their Bow Street detectives. Unlike the stipendiary system at Bow Street, the river police were full-time, salaried officers prohibited from taking private fees.[39] His other contribution was the concept of preventive policing; his police were to act as a highly visible deterrent to crime by their permanent presence on the Thames.[38] Colquhoun's innovations were a critical development leading up to Robert Peel's "new" police three decades later.[40]
+
+London was fast reaching a size unprecedented in world history, due to the onset of the Industrial Revolution.[41] It became clear that the locally maintained system of volunteer constables and "watchmen" was ineffective, both in detecting and preventing crime. A parliamentary committee was appointed to investigate the system of policing in London. Upon Sir Robert Peel being appointed as Home Secretary in 1822, he established a second and more effective committee, and acted upon its findings.
+
+Royal assent to the Metropolitan Police Act 1829 was given[42] and the Metropolitan Police Service was established on September 29, 1829 in London as the first modern and professional police force in the world.[43][44][45]
+
+Peel, widely regarded as the father of modern policing,[46] was heavily influenced by the social and legal philosophy of Jeremy Bentham, who called for a strong and centralised, but politically neutral, police force for the maintenance of social order, for the protection of people from crime and to act as a visible deterrent to urban crime and disorder.[47] Peel decided to standardise the police force as an official paid profession, to organise it in a civilian fashion, and to make it answerable to the public.[48]
+
+Due to public fears concerning the deployment of the military in domestic matters, Peel organised the force along civilian lines, rather than paramilitary. To appear neutral, the uniform was deliberately manufactured in blue, rather than red which was then a military colour, along with the officers being armed only with a wooden truncheon and a rattle to signal the need for assistance. Along with this, police ranks did not include military titles, with the exception of Sergeant.[49]
+
+To distance the new police force from the initial public view of it as a new tool of government repression, Peel publicised the so-called Peelian principles, which set down basic guidelines for ethical policing:[50][51]
+
+The 1829 Metropolitan Police Act created a modern police force by limiting the purview of the force and its powers, and envisioning it as merely an organ of the judicial system. Their job was apolitical; to maintain the peace and apprehend criminals for the courts to process according to the law.[52] This was very different from the "continental model" of the police force that had been developed in France, where the police force worked within the parameters of the absolutist state as an extension of the authority of the monarch and functioned as part of the governing state.
+
+In 1863, the Metropolitan Police were issued with the distinctive custodian helmet, and in 1884 they switched to the use of whistles that could be heard from much further away.[53] The Metropolitan Police became a model for the police forces in many countries, such as the United States, and most of the British Empire.[54][55] Bobbies can still be found in many parts of the Commonwealth of Nations.
+
+In Australia, the first police force having centralised command as well as jurisdiction over an entire colony was the South Australia Police, formed in 1838 under Henry Inman.
+
+However, whilst the New South Wales Police Force was established in 1862, it was made up from a large number of policing and military units operating within the then Colony of New South Wales and traces its links back to the Royal Marines. The passing of the Police Regulation Act of 1862 essentially tightly regulated and centralised all of the police forces operating throughout the Colony of New South Wales.
+
+The New South Wales Police Force remains the largest police force in Australia in terms of personnel and physical resources. It is also the only police force that requires its recruits to undertake university studies at the recruit level and has the recruit pay for their own education.
+
+In 1566, the first police investigator of Rio de Janeiro was recruited. By the 17th century, most captaincies already had local units with law enforcement functions. On July 9, 1775 a Cavalry Regiment was created in the state of Minas Gerais for maintaining law and order. In 1808, the Portuguese royal family relocated to Brazil, because of the French invasion of Portugal. King João VI established the "Intendência Geral de Polícia" (General Police Intendancy) for investigations. He also created a Royal Police Guard for Rio de Janeiro in 1809. In 1831, after independence, each province started organizing its local "military police", with order maintenance tasks. The Federal Railroad Police was created in 1852, Federal Highway Police, was established in 1928, and Federal Police in 1967.
+
+Established in 1729, the Royal Newfoundland Constabulary (RNC) was the first policing service founded in Canada. The establishment of modern policing services in the Canadas occurred during the 1830s, modelling their services after the London Metropolitan Police, and adopting the ideas of the Peelian principles.[56] The Toronto Police Service was established in 1834, whereas the Service de police de la Ville de Québec was established in 1840.[56]
+
+A national police service, the Dominion Police, was founded in 1868. Initially the Dominion Police provided security for parliament, but its responsibilities quickly grew. In 1870, Rupert's Land and the North-Western Territory were incorporated into the country. In an effort to police its newly acquired territory, the Canadian government established the North-West Mounted Police in 1873 (renamed Royal North-West Mounted Police in 1904).[56] In 1920, the Dominion Police, and the Royal Northwest Mounted Police were amalgamated into the Royal Canadian Mounted Police (RCMP).[56]
+
+The RCMP provides federal law enforcement; and law enforcement in eight provinces, and all three territories. The provinces of Ontario, and Quebec maintain their own provincial police forces, the Ontario Provincial Police (OPP), and the Sûreté du Québec (SQ). Policing in Newfoundland and Labrador is provided by the RCMP, and the RNC. The aforementioned services also provides municipal policing, although larger Canadian municipalities may establish form their own police service.
+
+In Lebanon, modern police were established in 1861, with creation of the Gendarmerie.[57]
+
+In India, the police are under the control of respective States and union territories and is known to be under State Police Services (SPS). The candidates selected for the SPS are usually posted as Deputy Superintendent of Police or Assistant Commissioner of Police once their probationary period ends. On prescribed satisfactory service in the SPS, the officers are nominated to the Indian Police Service.[58] The service color is usually dark blue and red, while the uniform color is Khaki.[59]
+
+In British North America, policing was initially provided by local elected officials. For instance, the New York Sheriff's Office was founded in 1626, and the Albany County Sheriff's Department in the 1660s. In the colonial period, policing was provided by elected sheriffs and local militias.
+
+In the 1700s, the Province of Carolina (later North- and South Carolina) established slave patrols in order to prevent slave rebellions and enslaved people from escaping.[60][61] For example, by 1785 the Charleston Guard and Watch had "a distinct chain of command, uniforms, sole responsibility for policing, salary, authorized use of force, and a focus on preventing 'crime'."[62]
+
+In 1789 the United States Marshals Service was established, followed by other federal services such as the U.S. Parks Police (1791)[63] and U.S. Mint Police (1792).[64] The first city police services were established in Philadelphia in 1751,[65] Richmond, Virginia in 1807,[66] Boston in 1838,[67] and New York in 1845.[68] The U.S. Secret Service was founded in 1865 and was for some time the main investigative body for the federal government.[69]
+
+In the American Old West, law enforcement was carried out by local sheriffs, rangers, constables, and federal marshals. There were also town marshals responsible for serving civil and criminal warrants, maintaining the jails, and carrying out arrests for petty crime.[70][71]
+
+In recent years, in addition to federal, state, and local forces, some special districts have been formed to provide extra police protection in designated areas. These districts may be known as neighborhood improvement districts, crime prevention districts, or security districts.[72]
+
+Michel Foucault claims that the contemporary concept of police as a paid and funded functionary of the state was developed by German and French legal scholars and practitioners in Public administration and Statistics in the 17th and early 18th centuries, most notably with Nicolas Delamare's Traité de la Police ("Treatise on the Police"), first published in 1705. The German Polizeiwissenschaft (Science of Police) first theorized by Philipp von Hörnigk a 17th-century Austrian Political economist and civil servant and much more famously by Johann Heinrich Gottlob Justi who produced an important theoretical work known as Cameral science on the formulation of police.[73] Foucault cites Magdalene Humpert author of Bibliographie der Kameralwissenschaften (1937) in which the author makes note of a substantial bibliography was produced of over 4000 pieces of the practice of Polizeiwissenschaft however, this maybe a mistranslation of Foucault's own work the actual source of Magdalene Humpert states over 14,000 items were produced from the 16th century dates ranging from 1520–1850.[74][75]
+
+As conceptualized by the Polizeiwissenschaft, according to Foucault the police had an administrative, economic and social duty ("procuring abundance"). It was in charge of demographic concerns and needed to be incorporated within the western political philosophy system of raison d'état and therefore giving the superficial appearance of empowering the population (and unwittingly supervising the population), which, according to mercantilist theory, was to be the main strength of the state. Thus, its functions largely overreached simple law enforcement activities and included public health concerns, urban planning (which was important because of the miasma theory of disease; thus, cemeteries were moved out of town, etc.), and surveillance of prices.[76]
+
+The concept of preventive policing, or policing to deter crime from taking place, gained influence in the late 18th century. Police Magistrate John Fielding, head of the Bow Street Runners, argued that "...it is much better to prevent even one man from being a rogue than apprehending and bringing forty to justice."[77]
+
+The Utilitarian philosopher, Jeremy Bentham, promoted the views of Italian Marquis Cesare Beccaria, and disseminated a translated version of "Essay on Crime in Punishment". Bentham espoused the guiding principle of "the greatest good for the greatest number:
+
+It is better to prevent crimes than to punish them. This is the chief aim of every good system of legislation, which is the art of leading men to the greatest possible happiness or to the least possible misery, according to calculation of all the goods and evils of life.[77]
+
+Patrick Colquhoun's influential work, A Treatise on the Police of the Metropolis (1797) was heavily influenced by Benthamite thought. Colquhoun's Thames River Police was founded on these principles, and in contrast to the Bow Street Runners, acted as a deterrent by their continual presence on the riverfront, in addition to being able to intervene if they spotted a crime in progress.[78]
+
+Edwin Chadwick's 1829 article, "Preventive police" in the London Review,[79] argued that prevention ought to be the primary concern of a police body, which was not the case in practice. The reason, argued Chadwick, was that "A preventive police would act more immediately by placing difficulties in obtaining the objects of temptation." In contrast to a deterrent of punishment, a preventive police force would deter criminality by making crime cost-ineffective – "crime doesn't pay". In the second draft of his 1829 Police Act, the "object" of the new Metropolitan Police, was changed by Robert Peel to the "principal object," which was the "prevention of crime."[80] Later historians would attribute the perception of England's "appearance of orderliness and love of public order" to the preventive principle entrenched in Peel's police system.[81]
+
+Development of modern police forces around the world was contemporary to the formation of the state, later defined by sociologist Max Weber as achieving a "monopoly on the legitimate use of physical force" and which was primarily exercised by the police and the military. Marxist theory situates the development of the modern state as part of the rise of capitalism, in which the police are one component of the bourgeoisie's repressive apparatus for subjugating the working class. By contrast, the Peelian principles argue that "the power of the police...is dependent on public approval of their existence, actions and behavior", a philosophy known as policing by consent.
+
+Police forces include both preventive (uniformed) police and detectives. Terminology varies from country to country. Police functions include protecting life and property, enforcing criminal law, criminal investigations, regulating traffic, crowd control, public safety duties, civil defense, emergency management, searching for missing persons, lost property and other duties concerned with public order. Regardless of size, police forces are generally organized as a hierarchy with multiple ranks. The exact structures and the names of rank vary considerably by country.
+
+See also: Uniform#Police
+
+The police who wear uniforms make up the majority of a police service's personnel. Their main duty is to respond to calls to the emergency telephone number. When not responding to these call-outs, they will do work aimed at preventing crime, such as patrols. The uniformed police are known by varying names such as preventive police, the uniform branch/division, administrative police, order police, the patrol bureau/division or patrol. In Australia and the United Kingdom, patrol personnel are also known as "general duties" officers.[82] Atypically, Brazil's preventive police are known as Military Police.[83]
+
+As implied by the name, uniformed police wear uniforms. They perform functions that require an immediate recognition of an officer's legal authority and a potential need for force. Most commonly this means intervening to stop a crime in progress and securing the scene of a crime that has already happened. Besides dealing with crime, these officers may also manage and monitor traffic, carry out community policing duties, maintain order at public events or carry out searches for missing people (in 2012, the latter accounted for 14% of police time in the United Kingdom).[84] As most of these duties must be available as a 24/7 service, uniformed police are required to do shift work.
+
+Police detectives are responsible for investigations and detective work. Detectives may be called Investigations Police, Judiciary/Judicial Police, and Criminal Police. In the UK, they are often referred to by the name of their department, the Criminal Investigation Department (CID). Detectives typically make up roughly 15–25% of a police service's personnel.
+
+Detectives, in contrast to uniformed police, typically wear 'business attire' in bureaucratic and investigative functions where a uniformed presence would be either a distraction or intimidating, but a need to establish police authority still exists. "Plainclothes" officers dress in attire consistent with that worn by the general public for purposes of blending in.
+
+In some cases, police are assigned to work "undercover", where they conceal their police identity to investigate crimes, such as organized crime or narcotics crime, that are unsolvable by other means. In some cases this type of policing shares aspects with espionage.
+
+The relationship between detective and uniformed branches varies by country. In the United States, there is high variation within the country itself. Many US police departments require detectives to spend some time on temporary assignments in the patrol division.[citation needed] The argument is that rotating officers helps the detectives to better understand the uniformed officers' work, to promote cross-training in a wider variety of skills, and prevent "cliques" that can contribute to corruption or other unethical behavior.[citation needed] Conversely, some countries regard detective work as being an entirely separate profession, with detectives working in separate agencies and recruited without having to serve in uniform. A common compromise in English-speaking countries is that most detectives are recruited from the uniformed branch, but once qualified they tend to spend the rest of their careers in the detective branch.
+
+Another point of variation is whether detectives have extra status. In some forces, such as the New York Police Department and Philadelphia Police Department, a regular detective holds a higher rank than a regular police officer. In others, such as British police forces and Canadian police forces, a regular detective has equal status with regular uniformed officers. Officers still have to take exams to move to the detective branch, but the move is regarded as being a specialization, rather than a promotion.
+
+Police services often include part-time or volunteer officers, some of whom have other jobs outside policing. These may be paid positions or entirely volunteer. These are known by a variety of names, such as reserves, auxiliary police or special constables.
+
+Other volunteer organizations work with the police and perform some of their duties. Groups in the U.S. including Retired and Senior Volunteer Program, Community Emergency Response Team and the Boy Scout's Police Explorers provide training, traffic and crowd control, disaster response and other policing duties. In the U.S., the Volunteers in Police Service program assists over 200,000 volunteers in almost 2,000 programs.[85] Volunteers may also work on the support staff. Examples of these schemes are Volunteers in Police Service in the US, Police Support Volunteers in the UK and Volunteers in Policing in New South Wales.
+
+Specialized preventive and detective groups, or Specialist Investigation Departments exist within many law enforcement organizations either for dealing with particular types of crime, such as traffic law enforcement, K9, crash investigation, homicide, or fraud; or for situations requiring specialized skills, such as underwater search, aviation, explosive device disposal ("bomb squad"), and computer crime.
+
+Most larger jurisdictions also employ specially selected and trained quasi-military units armed with military-grade weapons for the purposes of dealing with particularly violent situations beyond the capability of a patrol officer response, including high-risk warrant service and barricaded suspects. In the United States these units go by a variety of names, but are commonly known as SWAT (Special Weapons And Tactics) teams.
+
+In counterinsurgency-type campaigns, select and specially trained units of police armed and equipped as light infantry have been designated as police field forces who perform paramilitary-type patrols and ambushes whilst retaining their police powers in areas that were highly dangerous.[86]
+
+Because their situational mandate typically focuses on removing innocent bystanders from dangerous people and dangerous situations, not violent resolution, they are often equipped with non-lethal tactical tools like chemical agents, "flashbang" and concussion grenades, and rubber bullets. The Specialist Firearms Command (CO19)[87] of the Metropolitan Police in London is a group of armed police used in dangerous situations including hostage taking, armed robbery/assault and terrorism.
+
+Police may have administrative duties that are not directly related to enforcing the law, such as issuing firearms licenses. The extent that police have these functions varies among countries, with police in France, Germany, and other continental European countries handling such tasks to a greater extent than British counterparts.[82]
+
+Military police may refer to:
+
+Some Islamic societies have religious police, who enforce the application of Islamic Sharia law. Their authority may include the power to arrest unrelated men and women caught socializing, anyone engaged in homosexual behavior or prostitution; to enforce Islamic dress codes, and store closures during Islamic prayer time.[88][89]
+
+They enforce Muslim dietary laws, prohibit the consumption or sale of alcoholic beverages and pork, and seize banned consumer products and media regarded as un-Islamic, such as CDs/DVDs of various Western musical groups, television shows and film.[88][89] In Saudi Arabia, the Mutaween actively prevent the practice or proselytizing of non-Islamic religions within Saudi Arabia, where they are banned.[88][89]
+
+Most countries are members of the International Criminal Police Organization (Interpol), established to detect and fight transnational crime and provide for international co-operation and co-ordination of other police activities, such as notifying relatives of the death of foreign nationals. Interpol does not conduct investigations or arrests by itself, but only serves as a central point for information on crime, suspects and criminals. Political crimes are excluded from its competencies.
+
+The terms international policing, transnational policing, and/or global policing began to be used from the early 1990s onwards to describe forms of policing that transcended the boundaries of the sovereign nation-state (Nadelmann, 1993),[90] (Sheptycki, 1995).[91] These terms refer in variable ways to practices and forms for policing that, in some sense, transcend national borders. This includes a variety of practices, but international police cooperation, criminal intelligence exchange between police agencies working in different nation-states, and police development-aid to weak, failed or failing states are the three types that have received the most scholarly attention.
+
+Historical studies reveal that policing agents have undertaken a variety of cross-border police missions for many years (Deflem, 2002).[92] For example, in the 19th century a number of European policing agencies undertook cross-border surveillance because of concerns about anarchist agitators and other political radicals. A notable example of this was the occasional surveillance by Prussian police of Karl Marx during the years he remained resident in London. The interests of public police agencies in cross-border co-operation in the control of political radicalism and ordinary law crime were primarily initiated in Europe, which eventually led to the establishment of Interpol before the Second World War. There are also many interesting examples of cross-border policing under private auspices and by municipal police forces that date back to the 19th century (Nadelmann, 1993).[90] It has been established that modern policing has transgressed national boundaries from time to time almost from its inception. It is also generally agreed that in the post–Cold War era this type of practice became more significant and frequent (Sheptycki, 2000).[93]
+
+Not a lot of empirical work on the practices of inter/transnational information and intelligence sharing has been undertaken. A notable exception is James Sheptycki's study of police cooperation in the English Channel region (2002),[94] which provides a systematic content analysis of information exchange files and a description of how these transnational information and intelligence exchanges are transformed into police case-work. The study showed that transnational police information sharing was routinized in the cross-Channel region from 1968 on the basis of agreements directly between the police agencies and without any formal agreement between the countries concerned. By 1992, with the signing of the Schengen Treaty, which formalized aspects of police information exchange across the territory of the European Union, there were worries that much, if not all, of this intelligence sharing was opaque, raising questions about the efficacy of the accountability mechanisms governing police information sharing in Europe (Joubert and Bevers, 1996).[95]
+
+Studies of this kind outside of Europe are even rarer, so it is difficult to make generalizations, but one small-scale study that compared transnational police information and intelligence sharing practices at specific cross-border locations in North America and Europe confirmed that low visibility of police information and intelligence sharing was a common feature (Alain, 2001).[96] Intelligence-led policing is now common practice in most advanced countries (Ratcliffe, 2007)[97] and it is likely that police intelligence sharing and information exchange has a common morphology around the world (Ratcliffe, 2007).[97] James Sheptycki has analyzed the effects of the new information technologies on the organization of policing-intelligence and suggests that a number of 'organizational pathologies' have arisen that make the functioning of security-intelligence processes in transnational policing deeply problematic. He argues that transnational police information circuits help to "compose the panic scenes of the security-control society".[98] The paradoxical effect is that, the harder policing agencies work to produce security, the greater are feelings of insecurity.
+
+Police development-aid to weak, failed or failing states is another form of transnational policing that has garnered attention. This form of transnational policing plays an increasingly important role in United Nations peacekeeping and this looks set to grow in the years ahead, especially as the international community seeks to develop the rule of law and reform security institutions in States recovering from conflict (Goldsmith and Sheptycki, 2007)[99] With transnational police development-aid the imbalances of power between donors and recipients are stark and there are questions about the applicability and transportability of policing models between jurisdictions (Hills, 2009).[100]
+
+Perhaps the greatest question regarding the future development of transnational policing is: in whose interest is it?[citation needed] At a more practical level, the question translates into one about how to make transnational policing institutions democratically accountable (Sheptycki, 2004).[101] For example, according to the Global Accountability Report for 2007 (Lloyd, et al. 2007) Interpol had the lowest scores in its category (IGOs), coming in tenth with a score of 22% on overall accountability capabilities (p. 19).[102] As this report points out, and the existing academic literature on transnational policing seems to confirm, this is a secretive area and one not open to civil society involvement.[citation needed]
+
+In many jurisdictions, police officers carry firearms, primarily handguns, in the normal course of their duties. In the United Kingdom (except Northern Ireland), Iceland, Ireland, Norway, New Zealand,[103] and Malta, with the exception of specialist units, officers do not carry firearms as a matter of course. Norwegian police carry firearms in their vehicles, but not on their duty belts, and must obtain authorisation before the weapons can be removed from the vehicle.
+
+Police often have specialist units for handling armed offenders, and similar dangerous situations, and can (depending on local laws), in some extreme circumstances, call on the military (since Military Aid to the Civil Power is a role of many armed forces). Perhaps the most high-profile example of this was, in 1980 the Metropolitan Police handing control of the Iranian Embassy Siege to the Special Air Service.
+
+They can also be armed with non-lethal (more accurately known as "less than lethal" or "less-lethal" given that they can still be deadly[104]) weaponry, particularly for riot control. Non-lethal weapons include batons, tear gas, riot control agents, rubber bullets, riot shields, water cannons and electroshock weapons. Police officers typically carry handcuffs to restrain suspects. The use of firearms or deadly force is typically a last resort only to be used when necessary to save human life, although some jurisdictions (such as Brazil) allow its use against fleeing felons and escaped convicts. American police are allowed to use deadly force simply if they "think their life is in danger."[105] A "shoot-to-kill" policy was recently introduced in South Africa, which allows police to use deadly force against any person who poses a significant threat to them or civilians.[106] With the country having one of the highest rates of violent crime, president Jacob Zuma states that South Africa needs to handle crime differently from other countries.[107]
+
+Modern police forces make extensive use of two-way radio communications equipment, carried both on the person and installed in vehicles, to co-ordinate their work, share information, and get help quickly. In recent years, vehicle-installed mobile data terminals have enhanced the ability of police communications, enabling easier dispatching of calls, criminal background checks on persons of interest to be completed in a matter of seconds, and updating officers' daily activity log and other, required reports on a real-time basis. Other common pieces of police equipment include flashlights/torches, whistles, police notebooks and "ticket books" or citations. Some police departments have developed advanced computerized data display and communication systems to bring real time data to officers, one example being the NYPD's Domain Awareness System.
+
+Police vehicles are used for detaining, patrolling and transporting. The average police patrol vehicle is a specially modified, four door sedan (saloon in British English). Police vehicles are usually marked with appropriate logos and are equipped with sirens and flashing light bars to aid in making others aware of police presence.
+
+Unmarked vehicles are used primarily for sting operations or apprehending criminals without alerting them to their presence. Some police forces use unmarked or minimally marked cars for traffic law enforcement, since drivers slow down at the sight of marked police vehicles and unmarked vehicles make it easier for officers to catch speeders and traffic violators. This practice is controversial, with for example, New York State banning this practice in 1996 on the grounds that it endangered motorists who might be pulled over by people impersonating police officers.[108]
+
+Motorcycles are also commonly used, particularly in locations that a car may not be able to reach, to control potential public order situations involving meetings of motorcyclists and often in escort duties where motorcycle police officers can quickly clear a path for escorted vehicles. Bicycle patrols are used in some areas because they allow for more open interaction with the public. Bicycles are also commonly used by riot police to create makeshift barricades against protesters.[109] In addition, their quieter operation can facilitate approaching suspects unawares and can help in pursuing them attempting to escape on foot.
+
+Police forces use an array of specialty vehicles such as helicopters, airplanes, watercraft, mobile command posts, vans, trucks, all-terrain vehicles, motorcycles, and armored vehicles.
+
+Police cars may also contain fire extinguishers[110][111] or defibrillators.[112]
+
+The advent of the police car, two-way radio, and telephone in the early 20th century transformed policing into a reactive strategy that focused on responding to calls for service.[113] With this transformation, police command and control became more centralized.
+
+In the United States, August Vollmer introduced other reforms, including education requirements for police officers.[114] O.W. Wilson, a student of Vollmer, helped reduce corruption and introduce professionalism in Wichita, Kansas, and later in the Chicago Police Department.[115] Strategies employed by O.W. Wilson included rotating officers from community to community to reduce their vulnerability to corruption, establishing of a non-partisan police board to help govern the police force, a strict merit system for promotions within the department, and an aggressive recruiting drive with higher police salaries to attract professionally qualified officers.[116] During the professionalism era of policing, law enforcement agencies concentrated on dealing with felonies and other serious crime and conducting visible car patrols in between, rather than broader focus on crime prevention.[117]
+
+The Kansas City Preventive Patrol study in the early 1970s showed flaws in this strategy. It found that aimless car patrols did little to deter crime and often went unnoticed by the public. Patrol officers in cars had insufficient contact and interaction with the community, leading to a social rift between the two.[118] In the 1980s and 1990s, many law enforcement agencies began to adopt community policing strategies, and others adopted problem-oriented policing.
+
+Broken windows' policing was another, related approach introduced in the 1980s by James Q. Wilson and George L. Kelling, who suggested that police should pay greater attention to minor "quality of life" offenses and disorderly conduct. The concept behind this method is simple: broken windows, graffiti, and other physical destruction or degradation of property create an environment in which crime and disorder is more likely. The presence of broken windows and graffiti sends a message that authorities do not care and are not trying to correct problems in these areas. Therefore, correcting these small problems prevents more serious criminal activity.[119] The theory was popularised in the early 1990s by police chief William J. Bratton and New York City Mayor Rudy Giuliani.
+
+Building upon these earlier models, intelligence-led policing has also become an important strategy. Intelligence-led policing and problem-oriented policing are complementary strategies, both of which involve systematic use of information.[120] Although it still lacks a universally accepted definition, the crux of intelligence-led policing is an emphasis on the collection and analysis of information to guide police operations, rather than the reverse.[121]
+
+A related development is evidence-based policing. In a similar vein to evidence-based policy, evidence-based policing is the use of controlled experiments to find which methods of policing are more effective. Leading advocates of evidence-based policing include the criminologist Lawrence W. Sherman and philanthropist Jerry Lee. Findings from controlled experiments include the Minneapolis Domestic Violence Experiment,[122] evidence that patrols deter crime if they are concentrated in crime hotspots[123] and that restricting police powers to shoot suspects does not cause an increase in crime or violence against police officers.[124] Use of experiments to assess the usefulness of strategies has been endorsed by many police services and institutions, including the US Police Foundation and the UK College of Policing.
+
+In many nations, criminal procedure law has been developed to regulate officers' discretion, so that they do not arbitrarily or unjustly exercise their powers of arrest, search and seizure, and use of force. In the United States, Miranda v. Arizona led to the widespread use of Miranda warnings or constitutional warnings.
+
+In Miranda the court created safeguards against self-incriminating statements made after an arrest. The court held that "The prosecution may not use statements, whether exculpatory or inculpatory, stemming from questioning initiated by law enforcement officers after a person has been taken into custody or otherwise deprived of his freedom of action in any significant way, unless it demonstrates the use of procedural safeguards effective to secure the Fifth Amendment's privilege against self-incrimination"[125]
+
+Police in the United States are also prohibited from holding criminal suspects for more than a reasonable amount of time (usually 24–48 hours) before arraignment, using torture, abuse or physical threats to extract confessions, using excessive force to effect an arrest, and searching suspects' bodies or their homes without a warrant obtained upon a showing of probable cause. The four exceptions to the constitutional requirement of a search warrant are:
+
+In Terry v. Ohio (1968) the court divided seizure into two parts, the investigatory stop and arrest. The court further held that during an investigatory stop a police officer's search " [is] confined to what [is] minimally necessary to determine whether [a suspect] is armed, and the intrusion, which [is] made for the sole purpose of protecting himself and others nearby, [is] confined to ascertaining the presence of weapons" (U.S. Supreme Court). Before Terry, every police encounter constituted an arrest, giving the police officer the full range of search authority. Search authority during a Terry stop (investigatory stop) is limited to weapons only.[125]
+
+Using deception for confessions is permitted, but not coercion. There are exceptions or exigent circumstances such as an articulated need to disarm a suspect or searching a suspect who has already been arrested (Search Incident to an Arrest). The Posse Comitatus Act severely restricts the use of the military for police activity, giving added importance to police SWAT units.
+
+British police officers are governed by similar rules, such as those introduced to England and Wales under the Police and Criminal Evidence Act 1984 (PACE), but generally have greater powers. They may, for example, legally search any suspect who has been arrested, or their vehicles, home or business premises, without a warrant, and may seize anything they find in a search as evidence.
+
+All police officers in the United Kingdom, whatever their actual rank, are 'constables' in terms of their legal position. This means that a newly appointed constable has the same arrest powers as a Chief Constable or Commissioner. However, certain higher ranks have additional powers to authorize certain aspects of police operations, such as a power to authorize a search of a suspect's house (section 18 PACE in England and Wales) by an officer of the rank of Inspector, or the power to authorize a suspect's detention beyond 24 hours by a Superintendent.
+
+Police services commonly include units for investigating crimes committed by the police themselves. These units are typically called Inspectorate-General, or in the US, "internal affairs". In some countries separate organizations outside the police exist for such purposes, such as the British Independent Office for Police Conduct. However, due to American laws around Qualified Immunity, it has become increasingly difficult to investigate and charge police misconduct & crimes.[126]
+
+Likewise, some state and local jurisdictions, for example, Springfield, Illinois[127] have similar outside review organizations. The Police Service of Northern Ireland is investigated by the Police Ombudsman for Northern Ireland, an external agency set up as a result of the Patten report into policing the province. In the Republic of Ireland the Garda Síochána is investigated by the Garda Síochána Ombudsman Commission, an independent commission that replaced the Garda Complaints Board in May 2007.
+
+The Special Investigations Unit of Ontario, Canada, is one of only a few civilian agencies around the world responsible for investigating circumstances involving police and civilians that have resulted in a death, serious injury, or allegations of sexual assault. The agency has made allegations of insufficient cooperation from various police services hindering their investigations.[128]
+
+In Hong Kong, any allegations of corruption within the police will be investigated by the Independent Commission Against Corruption and the Independent Police Complaints Council, two agencies which are independent of the police force.
+
+Due to a long-term decline in public confidence for law enforcement in the United States, body cameras worn by police officers are under consideration.[129]
+
+Police forces also find themselves under criticism for their use of force, particularly deadly force. Specifically, tension increases when a police officer of one ethnic group harms or kills a suspect of another one.[citation needed] In the United States, such events occasionally spark protests and accusations of racism against police and allegations that police departments practice racial profiling.
+
+In the United States since the 1960s, concern over such issues has increasingly weighed upon law enforcement agencies, courts and legislatures at every level of government. Incidents such as the 1965 Watts Riots, the videotaped 1991 beating by Los Angeles Police officers of Rodney King, and the riot following their acquittal have been suggested by some people to be evidence that U.S. police are dangerously lacking in appropriate controls.
+
+The fact that this trend has occurred contemporaneously with the rise of the civil rights movement, the "War on Drugs", and a precipitous rise in violent crime from the 1960s to the 1990s has made questions surrounding the role, administration and scope of police authority increasingly complicated.[citation needed]
+
+Police departments and the local governments that oversee them in some jurisdictions have attempted to mitigate some of these issues through community outreach programs and community policing to make the police more accessible to the concerns of local communities, by working to increase hiring diversity, by updating training of police in their responsibilities to the community and under the law, and by increased oversight within the department or by civilian commissions.
+
+In cases in which such measures have been lacking or absent, civil lawsuits have been brought by the United States Department of Justice against local law enforcement agencies, authorized under the 1994 Violent Crime Control and Law Enforcement Act. This has compelled local departments to make organizational changes, enter into consent decree settlements to adopt such measures, and submit to oversight by the Justice Department.[130]
+
+In May 2020, a global movement to increase scrutiny on police violence and defund militarization efforts grew in popularity—starting in Minneapolis, Minnesota with the killing of George Floyd. Calls for full defunding of the police and abolition of the police gained larger support as more criticized systemic racism in policing.[131]
+
+Since 1855, the Supreme Court of the United States has consistently ruled that law enforcement officers have no duty to protect any individual, despite the motto "protect and serve". Their duty is to enforce the law in general. The first such case was in 1855.[132] The most recent in 2005: Castle Rock v. Gonzales.[133]
+
+In contrast, the police are entitled to protect private rights in some jurisdictions. To ensure that the police would not interfere in the regular competencies of the courts of law, some police acts require that the police may only interfere in such cases where protection from courts cannot be obtained in time, and where, without interference of the police, the realization of the private right would be impeded.[134] This would, for example, allow police to establish a restaurant guest's identity and forward it to the innkeeper in a case where the guest cannot pay the bill at nighttime because his wallet had just been stolen from the restaurant table.
+
+In addition, there are federal law enforcement agencies in the United States whose mission includes providing protection for executives such as the president and accompanying family members, visiting foreign dignitaries, and other high-ranking individuals.[135][better source needed] Such agencies include the U.S. Secret Service and the U.S. Park Police.
+
+Police forces are usually organized and funded by some level of government. The level of government responsible for policing varies from place to place, and may be at the national, regional or local level. Some countries have police forces that serve the same territory, with their jurisdiction depending on the type of crime or other circumstances. Other countries, such as Austria, Chile, Israel, New Zealand, the Philippines, South Africa and Sweden, have a single national police force.[136]
+
+In some places with multiple national police forces, one common arrangement is to have a civilian police force and a paramilitary gendarmerie, such as the Police Nationale and National Gendarmerie in France.[82] The French policing system spread to other countries through the Napoleonic Wars[137] and the French colonial empire.[138][139] Another example is the Policía Nacional and Guardia Civil in Spain. In both France and Spain, the civilian force polices urban areas and the paramilitary force polices rural areas. Italy has a similar arrangement with the Polizia di Stato and Carabinieri, though their jurisdictions overlap more. Some countries have separate agencies for uniformed police and detectives, such as the Military Police and Civil Police in Brazil and the Carabineros and Investigations Police in Chile.
+
+Other countries have sub-national police forces, but for the most part their jurisdictions do not overlap. In many countries, especially federations, there may be two or more tiers of police force, each serving different levels of government and enforcing different subsets of the law. In Australia and Germany, the majority of policing is carried out by state (i.e. provincial) police forces, which are supplemented by a federal police force. Though not a federation, the United Kingdom has a similar arrangement, where policing is primarily the responsibility of a regional police force and specialist units exist at the national level. In Canada, the Royal Canadian Mounted Police (RCMP) are the federal police, while municipalities can decide whether to run a local police service or to contract local policing duties to a larger one. Most urban areas have a local police service, while most rural areas contract it to the RCMP, or to the provincial police in Ontario and Quebec.
+
+The United States has a highly decentralized and fragmented system of law enforcement, with over 17,000 state and local law enforcement agencies.[140] These agencies include local police, county law enforcement (often in the form of a sheriff's office, or county police), state police and federal law enforcement agencies. Federal agencies, such as the FBI, only have jurisdiction over federal crimes or those that involve more than one state. Other federal agencies have jurisdiction over a specific type of crime. Examples include the Federal Protective Service, which patrols and protects government buildings; the postal police, which protect postal buildings, vehicles and items; the Park Police, which protect national parks; and Amtrak Police, which patrol Amtrak stations and trains. There are also some government agencies that perform police functions in addition to other duties, such as the Coast Guard.

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+
+
+The Amazon rainforest,[a] alternatively, the Amazon Jungle, also known in English as Amazonia, is a moist broadleaf tropical rainforest in the Amazon biome that covers most of the Amazon basin of South America. This basin encompasses 7,000,000 km2 (2,700,000 sq mi), of which 5,500,000 km2 (2,100,000 sq mi) are covered by the rainforest. This region includes territory belonging to nine nations.
+
+The majority of the forest is contained within Brazil, with 60% of the rainforest, followed by Peru with 13%, Colombia with 10%, and with minor amounts in Venezuela, Ecuador, Bolivia, Guyana, Suriname and French Guiana. Four nations have "Amazonas" as the name of one of their first-level administrative regions and France uses the name "Guiana Amazonian Park" for its rainforest protected area. The Amazon represents over half of the planet's remaining rainforests,[2] and comprises the largest and most biodiverse tract of tropical rainforest in the world, with an estimated 390 billion individual trees divided into 16,000 species.[3]
+
+The name Amazon is said to arise from a war Francisco de Orellana fought with the Tapuyas and other tribes. The women of the tribe fought alongside the men, as was their custom.[4] Orellana derived the name Amazonas from the Amazons of Greek mythology, described by Herodotus and Diodorus.[4]
+
+Tribal societies are well capable of escalation to all-out wars between tribes. Thus, in the Amazonas, there was perpetual animosity between the neighboring tribes of the Jivaro. Several tribes of the Jivaroan group, including the Shuar, practised headhunting for trophies and headshrinking.[5] The accounts of missionaries to the area in the borderlands between Brazil and Venezuela have recounted constant infighting in the Yanomami tribes. More than a third of the Yanomamo males, on average, died from warfare.[6]
+
+During the Amazon rubber boom it is estimated that diseases brought by immigrants, such as typhus and malaria, killed 40,000 native Amazonians.[7]
+
+Nine countries share the Amazon basin—most of the rainforest, 58.4%, is contained within the borders of Brazil. The other eight countries include Peru with 12.8%, Bolivia with 7.7%, Colombia with 7.1%, Venezuela with 6.1%, Guyana with 3.1%, Suriname with 2.5%, French Guyana with 1.4%, and Ecuador with 1%.[8]
+
+The rainforest likely formed during the Eocene era (from 56 million years to 33.9 million years ago). It appeared following a global reduction of tropical temperatures when the Atlantic Ocean had widened sufficiently to provide a warm, moist climate to the Amazon basin. The rainforest has been in existence for at least 55 million years, and most of the region remained free of savanna-type biomes at least until the current ice age when the climate was drier and savanna more widespread.[9][10]
+
+Following the Cretaceous–Paleogene extinction event, the extinction of the dinosaurs and the wetter climate may have allowed the tropical rainforest to spread out across the continent. From 66–34 Mya, the rainforest extended as far south as 45°. Climate fluctuations during the last 34 million years have allowed savanna regions to expand into the tropics. During the Oligocene, for example, the rainforest spanned a relatively narrow band. It expanded again during the Middle Miocene, then retracted to a mostly inland formation at the last glacial maximum.[11] However, the rainforest still managed to thrive during these glacial periods, allowing for the survival and evolution of a broad diversity of species.[12]
+
+During the mid-Eocene, it is believed that the drainage basin of the Amazon was split along the middle of the continent by the Purus Arch. Water on the eastern side flowed toward the Atlantic, while to the west water flowed toward the Pacific across the Amazonas Basin. As the Andes Mountains rose, however, a large basin was created that enclosed a lake; now known as the Solimões Basin. Within the last 5–10 million years, this accumulating water broke through the Purus Arch, joining the easterly flow toward the Atlantic.[13][14]
+
+There is evidence that there have been significant changes in the Amazon rainforest vegetation over the last 21,000 years through the last glacial maximum (LGM) and subsequent deglaciation. Analyses of sediment deposits from Amazon basin paleolakes and the Amazon Fan indicate that rainfall in the basin during the LGM was lower than for the present, and this was almost certainly associated with reduced moist tropical vegetation cover in the basin.[15] There is a debate, however, over how extensive this reduction was. Some scientists argue that the rainforest was reduced to small, isolated refugia separated by open forest and grassland;[16] other scientists argue that the rainforest remained largely intact but extended less far to the north, south, and east than is seen today.[17] This debate has proved difficult to resolve because the practical limitations of working in the rainforest mean that data sampling is biased away from the center of the Amazon basin, and both explanations are reasonably well supported by the available data.
+
+More than 56% of the dust fertilizing the Amazon rainforest comes from the Bodélé depression in Northern Chad in the Sahara desert. The dust contains phosphorus, important for plant growth. The yearly Sahara dust replaces the equivalent amount of phosphorus washed away yearly in Amazon soil from rains and floods.[18]
+
+NASA's CALIPSO satellite has measured the amount of dust transported by wind from the Sahara to the Amazon: an average 182 million tons of dust are windblown out of the Sahara each year, at 15 degrees west longitude, across 2,600 km (1,600 mi) over the Atlantic Ocean (some dust falls into the Atlantic), then at 35 degrees West longitude at the eastern coast of South America, 27.7 million tons (15%) of dust fall over the Amazon basin (22 million tons of it consisting of phosphorus), 132 million tons of dust remain in the air, 43 million tons of dust are windblown and falls on the Caribbean Sea, past 75 degrees west longitude.[19]
+
+CALIPSO uses a laser range finder to scan the Earth's atmosphere for the vertical distribution of dust and other aerosols. CALIPSO regularly tracks the Sahara-Amazon dust plume. CALIPSO has measured variations in the dust amounts transported – an 86 percent drop between the highest amount of dust transported in 2007 and the lowest in 2011.
+
+A possibility causing the variation is the Sahel, a strip of semi-arid land on the southern border of the Sahara. When rain amounts in the Sahel are higher, the volume of dust is lower. The higher rainfall could make more vegetation grow in the Sahel, leaving less sand exposed to winds to blow away.[20]
+
+Amazon phosphorus also comes as smoke due to biomass burning in Africa.[21][22]
+
+Based on archaeological evidence from an excavation at Caverna da Pedra Pintada, human inhabitants first settled in the Amazon region at least 11,200 years ago.[24] Subsequent development led to late-prehistoric settlements along the periphery of the forest by AD 1250, which induced alterations in the forest cover.[25]
+
+For a long time, it was thought that the Amazon rainforest was never more than sparsely populated, as it was impossible to sustain a large population through agriculture given the poor soil. Archeologist Betty Meggers was a prominent proponent of this idea, as described in her book Amazonia: Man and Culture in a Counterfeit Paradise. She claimed that a population density of 0.2 inhabitants per square kilometre (0.52/sq mi) is the maximum that can be sustained in the rainforest through hunting, with agriculture needed to host a larger population.[26] However, recent anthropological findings have suggested that the region was actually densely populated. Some 5 million people may have lived in the Amazon region in AD 1500, divided between dense coastal settlements, such as that at Marajó, and inland dwellers.[27] By 1900, the population had fallen to 1 million and by the early 1980s it was less than 200,000.[27]
+
+The first European to travel the length of the Amazon River was Francisco de Orellana in 1542.[28] The BBC's Unnatural Histories presents evidence that Orellana, rather than exaggerating his claims as previously thought, was correct in his observations that a complex civilization was flourishing along the Amazon in the 1540s. It is believed that civilization was later devastated by the spread of diseases from Europe, such as smallpox.[29]. This civilization was investigated by the British explorer Percy Fawcett in the early twentieth century.  The results of his expeditions were inconclusive and he disappeared mysteriously on his last trip.  His name for this lost civilization was the City of Z.
+
+Since the 1970s, numerous geoglyphs have been discovered on deforested land dating between AD 1–1250, furthering claims about Pre-Columbian civilizations.[30][31] Ondemar Dias is accredited with first discovering the geoglyphs in 1977, and Alceu Ranzi is credited with furthering their discovery after flying over Acre.[29][32] The BBC's Unnatural Histories presented evidence that the Amazon rainforest, rather than being a pristine wilderness, has been shaped by man for at least 11,000 years through practices such as forest gardening and terra preta.[29] Terra preta is found over large areas in the Amazon forest; and is now widely accepted as a product of indigenous soil management. The development of this fertile soil allowed agriculture and silviculture in the previously hostile environment; meaning that large portions of the Amazon rainforest are probably the result of centuries of human management, rather than naturally occurring as has previously been supposed.[33] In the region of the Xingu tribe, remains of some of these large settlements in the middle of the Amazon forest were found in 2003 by Michael Heckenberger and colleagues of the University of Florida. Among those were evidence of roads, bridges and large plazas.[34]
+
+Wet tropical forests are the most species-rich biome, and tropical forests in the Americas are consistently more species rich than the wet forests in Africa and Asia.[35] As the largest tract of tropical rainforest in the Americas, the Amazonian rainforests have unparalleled biodiversity. One in ten known species in the world lives in the Amazon rainforest.[36] This constitutes the largest collection of living plants and animal species in the world.
+
+The region is home to about 2.5 million insect species,[37] tens of thousands of plants, and some 2,000 birds and mammals. To date, at least 40,000 plant species, 2,200 fishes,[38] 1,294 birds, 427 mammals, 428 amphibians, and 378 reptiles have been scientifically classified in the region.[39] One in five of all bird species are found in the Amazon rainforest, and one in five of the fish species live in Amazonian rivers and streams. Scientists have described between 96,660 and 128,843 invertebrate species in Brazil alone.[40]
+
+The biodiversity of plant species is the highest on Earth with one 2001 study finding a quarter square kilometer (62 acres) of Ecuadorian rainforest supports more than 1,100 tree species.[41] A study in 1999 found one square kilometer (247 acres) of Amazon rainforest can contain about 90,790 tonnes of living plants. The average plant biomass is estimated at 356 ± 47 tonnes per hectare.[42] To date, an estimated 438,000 species of plants of economic and social interest have been registered in the region with many more remaining to be discovered or catalogued.[43] The total number of tree species in the region is estimated at 16,000.[3]
+
+The green leaf area of plants and trees in the rainforest varies by about 25% as a result of seasonal changes. Leaves expand during the dry season when sunlight is at a maximum, then undergo abscission in the cloudy wet season. These changes provide a balance of carbon between photosynthesis and respiration.[44]
+
+The rainforest contains several species that can pose a hazard. Among the largest predatory creatures are the black caiman, jaguar, cougar, and anaconda. In the river, electric eels can produce an electric shock that can stun or kill, while piranha are known to bite and injure humans.[45] Various species of poison dart frogs secrete lipophilic alkaloid toxins through their flesh. There are also numerous parasites and disease vectors. Vampire bats dwell in the rainforest and can spread the rabies virus.[46] Malaria, yellow fever and dengue fever can also be contracted in the Amazon region.
+
+Hoatzin
+
+Mygalomorphae
+
+Howler monkey
+
+Heliconia
+
+Brown-throated sloth
+
+Emperor tamarin
+
+Blue poison dart frog
+
+South American jaguar
+
+Bald uakari
+
+Bullet ants have an extremely painful sting
+
+Parrots at clay lick in Yasuni National Park, Ecuador
+
+Deforestation is the conversion of forested areas to non-forested areas. The main sources of deforestation in the Amazon are human settlement and development of the land.[47] In 2018, about 17% of the Amazon rainforest was already destroyed. Research suggests that upon reaching about 20–25% (hence 3–8% more), the tipping point to flip it into a non-forest ecosystems – degraded savannah – (in eastern, southern and central Amazonia) will be reached.[48][49]
+
+Prior to the early 1960s, access to the forest's interior was highly restricted, and the forest remained basically intact.[50] Farms established during the 1960s were based on crop cultivation and the slash and burn method. However, the colonists were unable to manage their fields and the crops because of the loss of soil fertility and weed invasion.[51] The soils in the Amazon are productive for just a short period of time, so farmers are constantly moving to new areas and clearing more land.[51] These farming practices led to deforestation and caused extensive environmental damage.[52] Deforestation is considerable, and areas cleared of forest are visible to the naked eye from outer space.
+
+In the 1970s, construction began on the Trans-Amazonian highway. This highway represented a major threat to the Amazon rainforest.[53] The highway still has not been completed, limiting the environmental damage.
+
+Between 1991 and 2000, the total area of forest lost in the Amazon rose from 415,000 to 587,000 km2 (160,000 to 227,000 sq mi), with most of the lost forest becoming pasture for cattle.[54] Seventy percent of formerly forested land in the Amazon, and 91% of land deforested since 1970, have been used for livestock pasture.[55][56] Currently, Brazil is the second-largest global producer of soybeans after the United States. New research however, conducted by Leydimere Oliveira et al., has shown that the more rainforest is logged in the Amazon, the less precipitation reaches the area and so the lower the yield per hectare becomes. So despite the popular perception, there has been no economical advantage for Brazil from logging rainforest zones and converting these to pastoral fields.[57]
+
+The needs of soy farmers have been used to justify many of the controversial transportation projects that are currently developing in the Amazon. The first two highways successfully opened up the rainforest and led to increased settlement and deforestation. The mean annual deforestation rate from 2000 to 2005 (22,392 km2 or 8,646 sq mi per year) was 18% higher than in the previous five years (19,018 km2 or 7,343 sq mi per year).[58] Although deforestation declined significantly in the Brazilian Amazon between 2004 and 2014, there has been an increase to the present day.[59]
+
+Since the discovery of fossil fuel reservoirs in the Amazon rainforest, oil drilling activity has steadily increased, peaking in the Western Amazon in the 1970s and ushering another drilling boom in the 2000s.[60] As oil companies have to set up their operations by opening roads through forests, which often contributes to deforestation in the region.[61]
+
+The European Union–Mercosur free trade agreement, which would form one of the world's largest free trade areas, has been denounced by environmental activists and indigenous rights campaigners.[62] The fear is that the deal could lead to more deforestation of the Amazon rainforest as it expands market access to Brazilian beef.[63]
+
+There have been 72,843 fires in Brazil in 2019, with more than half within the Amazon region.[64][65][66]  In August 2019 there were a record number of fires.[67] Deforestation in the Brazilian Amazon rose more than 88% in June 2019 compared with the same month in 2018.[68]
+
+NASA satellite observation of deforestation in the Mato Grosso state of Brazil. The transformation from forest to farm is evident by the paler square shaped areas under development.
+
+Fires and deforestation in the state of Rondônia
+
+One consequence of forest clearing in the Amazon: thick smoke that hangs over the forest
+
+Impact of deforestation on natural habitat of trees
+
+Environmentalists are concerned about loss of biodiversity that will result from destruction of the forest, and also about the release of the carbon contained within the vegetation, which could accelerate global warming. Amazonian evergreen forests account for about 10% of the world's terrestrial primary productivity and 10% of the carbon stores in ecosystems[69] – of the order of 1.1 × 1011 metric tonnes of carbon.[70] Amazonian forests are estimated to have accumulated 0.62 ± 0.37 tons of carbon per hectare per year between 1975 and 1996.[70]
+
+One computer model of future climate change caused by greenhouse gas emissions shows that the Amazon rainforest could become unsustainable under conditions of severely reduced rainfall and increased temperatures, leading to an almost complete loss of rainforest cover in the basin by 2100.[71][72] However, simulations of Amazon basin climate change across many different models are not consistent in their estimation of any rainfall response, ranging from weak increases to strong decreases.[73] The result indicates that the rainforest could be threatened though the 21st century by climate change in addition to deforestation.
+
+In 1989, environmentalist C.M. Peters and two colleagues stated there is economic as well as biological incentive to protecting the rainforest. One hectare in the Peruvian Amazon has been calculated to have a value of $6820 if intact forest is sustainably harvested for fruits, latex, and timber; $1000 if clear-cut for commercial timber (not sustainably harvested); or $148 if used as cattle pasture.[74]
+
+As indigenous territories continue to be destroyed by deforestation and ecocide, such as in the Peruvian Amazon[75] indigenous peoples' rainforest communities continue to disappear, while others, like the Urarina continue to struggle to fight for their cultural survival and the fate of their forested territories. Meanwhile, the relationship between non-human primates in the subsistence and symbolism of indigenous lowland South American peoples has gained increased attention, as have ethno-biology and community-based conservation efforts.
+
+From 2002 to 2006, the conserved land in the Amazon rainforest almost tripled and deforestation rates dropped up to 60%. About 1,000,000 km2 (250,000,000 acres) have been put onto some sort of conservation, which adds up to a current amount of 1,730,000 km2 (430,000,000 acres).[76]
+
+In April 2019, the Ecuadorian court stopped oil exploration activities in 180,000 hectares (440,000 acres) of the Amazon rainforest.[77]
+
+In July 2019, the Ecuadorian court forbade the government to sell territory with forests to oil companies.[78] In September 2019, the US and Brazil agreed to promote private-sector development in the Amazon. They also pledged a $100m  biodiversity conservation fund for the Amazon led by the private sector. Brazil's foreign minister stated that opening the rain-forest to economic development was the only way to protect it.[79]
+
+Anthropogenic emission of greenhouse gases broken down by sector for the year 2000.
+
+Aerosols over the Amazon each September for four burning seasons (2005 through 2008). The aerosol scale (yellow to dark reddish-brown) indicates the relative amount of particles that absorb sunlight.
+
+Aerial roots of red mangrove on an Amazonian river.
+
+A 2009 study found that a 4 °C rise (above pre-industrial levels) in global temperatures by 2100 would kill 85% of the Amazon rainforest while a temperature rise of 3 °C would kill some 75% of the Amazon.[80]
+
+Deforestation in the Amazon rainforest region has a negative impact on local climate.[81] It was one of the main causes of the severe drought  of 2014–2015 in Brazil.[82][83] This is because the moisture from the forests is important to the rainfall in Brazil, Paraguay and Argentina. Half of the rainfall in the Amazon area is produced by the forests.[84]
+
+The use of remotely sensed data is dramatically improving conservationists' knowledge of the Amazon basin. Given the objectivity and lowered costs of satellite-based land cover analysis, it appears likely that remote sensing technology will be an integral part of assessing the extent and damage of deforestation in the basin.[85] Furthermore, remote sensing is the best and perhaps only possible way to study the Amazon on a large scale.[86]
+
+The use of remote sensing for the conservation of the Amazon is also being used by the indigenous tribes of the basin to protect their tribal lands from commercial interests. Using handheld GPS devices and programs like Google Earth, members of the Trio Tribe, who live in the rainforests of southern Suriname, map out their ancestral lands to help strengthen their territorial claims.[87] Currently, most tribes in the Amazon do not have clearly defined boundaries, making it easier for commercial ventures to target their territories.
+
+To accurately map the Amazon's biomass and subsequent carbon related emissions, the classification of tree growth stages within different parts of the forest is crucial. In 2006, Tatiana Kuplich organized the trees of the Amazon into four categories: mature forest, regenerating forest [less than three years], regenerating forest [between three and five years of regrowth], and regenerating forest [eleven to eighteen years of continued development].[88] The researcher used a combination of synthetic aperture radar (SAR) and Thematic Mapper (TM) to accurately place the different portions of the Amazon into one of the four classifications.
+
+In 2005, parts of the Amazon basin experienced the worst drought in one hundred years,[89] and there were indications that 2006 may have been a second successive year of drought.[90] A 23 July 2006 article in the UK newspaper The Independent reported the Woods Hole Research Center results, showing that the forest in its present form could survive only three years of drought.[91][92] Scientists at the Brazilian National Institute of Amazonian Research argued in the article that this drought response, coupled with the effects of deforestation on regional climate, are pushing the rainforest towards a "tipping point" where it would irreversibly start to die.[93] It concluded that the forest is on the brink of[vague] being turned into savanna or desert, with catastrophic consequences for the world's climate.[citation needed]
+
+According to the World Wide Fund for Nature, the combination of climate change and deforestation increases the drying effect of dead trees that fuels forest fires.[94]
+
+In 2010, the Amazon rainforest experienced another severe drought, in some ways more extreme than the 2005 drought. The affected region was approximately 3,000,000 km2 (1,160,000 sq mi) of rainforest, compared with 1,900,000 km2 (734,000 sq mi) in 2005. The 2010 drought had three epicenters where vegetation died off, whereas in 2005, the drought was focused on the southwestern part. The findings were published in the journal Science. In a typical year, the Amazon absorbs 1.5 gigatons of carbon dioxide; during 2005 instead 5 gigatons were released and in 2010 8 gigatons were released.[95][96] Additional severe droughts occurred in 2010, 2015, and 2016.[97]
+
+In 2019 Brazil's protections of the Amazon rainforest were slashed, resulting in a severe loss of trees.[98] According to Brazil's National Institute for Space Research (INPE), deforestation in the Brazilian Amazon rose more than 50% in the first three months of 2020 compared to the same three-month period in 2019.[99]

en/2037.html.txt

@@ -0,0 +1,133 @@
+
+
+The Amazon rainforest,[a] alternatively, the Amazon Jungle, also known in English as Amazonia, is a moist broadleaf tropical rainforest in the Amazon biome that covers most of the Amazon basin of South America. This basin encompasses 7,000,000 km2 (2,700,000 sq mi), of which 5,500,000 km2 (2,100,000 sq mi) are covered by the rainforest. This region includes territory belonging to nine nations.
+
+The majority of the forest is contained within Brazil, with 60% of the rainforest, followed by Peru with 13%, Colombia with 10%, and with minor amounts in Venezuela, Ecuador, Bolivia, Guyana, Suriname and French Guiana. Four nations have "Amazonas" as the name of one of their first-level administrative regions and France uses the name "Guiana Amazonian Park" for its rainforest protected area. The Amazon represents over half of the planet's remaining rainforests,[2] and comprises the largest and most biodiverse tract of tropical rainforest in the world, with an estimated 390 billion individual trees divided into 16,000 species.[3]
+
+The name Amazon is said to arise from a war Francisco de Orellana fought with the Tapuyas and other tribes. The women of the tribe fought alongside the men, as was their custom.[4] Orellana derived the name Amazonas from the Amazons of Greek mythology, described by Herodotus and Diodorus.[4]
+
+Tribal societies are well capable of escalation to all-out wars between tribes. Thus, in the Amazonas, there was perpetual animosity between the neighboring tribes of the Jivaro. Several tribes of the Jivaroan group, including the Shuar, practised headhunting for trophies and headshrinking.[5] The accounts of missionaries to the area in the borderlands between Brazil and Venezuela have recounted constant infighting in the Yanomami tribes. More than a third of the Yanomamo males, on average, died from warfare.[6]
+
+During the Amazon rubber boom it is estimated that diseases brought by immigrants, such as typhus and malaria, killed 40,000 native Amazonians.[7]
+
+Nine countries share the Amazon basin—most of the rainforest, 58.4%, is contained within the borders of Brazil. The other eight countries include Peru with 12.8%, Bolivia with 7.7%, Colombia with 7.1%, Venezuela with 6.1%, Guyana with 3.1%, Suriname with 2.5%, French Guyana with 1.4%, and Ecuador with 1%.[8]
+
+The rainforest likely formed during the Eocene era (from 56 million years to 33.9 million years ago). It appeared following a global reduction of tropical temperatures when the Atlantic Ocean had widened sufficiently to provide a warm, moist climate to the Amazon basin. The rainforest has been in existence for at least 55 million years, and most of the region remained free of savanna-type biomes at least until the current ice age when the climate was drier and savanna more widespread.[9][10]
+
+Following the Cretaceous–Paleogene extinction event, the extinction of the dinosaurs and the wetter climate may have allowed the tropical rainforest to spread out across the continent. From 66–34 Mya, the rainforest extended as far south as 45°. Climate fluctuations during the last 34 million years have allowed savanna regions to expand into the tropics. During the Oligocene, for example, the rainforest spanned a relatively narrow band. It expanded again during the Middle Miocene, then retracted to a mostly inland formation at the last glacial maximum.[11] However, the rainforest still managed to thrive during these glacial periods, allowing for the survival and evolution of a broad diversity of species.[12]
+
+During the mid-Eocene, it is believed that the drainage basin of the Amazon was split along the middle of the continent by the Purus Arch. Water on the eastern side flowed toward the Atlantic, while to the west water flowed toward the Pacific across the Amazonas Basin. As the Andes Mountains rose, however, a large basin was created that enclosed a lake; now known as the Solimões Basin. Within the last 5–10 million years, this accumulating water broke through the Purus Arch, joining the easterly flow toward the Atlantic.[13][14]
+
+There is evidence that there have been significant changes in the Amazon rainforest vegetation over the last 21,000 years through the last glacial maximum (LGM) and subsequent deglaciation. Analyses of sediment deposits from Amazon basin paleolakes and the Amazon Fan indicate that rainfall in the basin during the LGM was lower than for the present, and this was almost certainly associated with reduced moist tropical vegetation cover in the basin.[15] There is a debate, however, over how extensive this reduction was. Some scientists argue that the rainforest was reduced to small, isolated refugia separated by open forest and grassland;[16] other scientists argue that the rainforest remained largely intact but extended less far to the north, south, and east than is seen today.[17] This debate has proved difficult to resolve because the practical limitations of working in the rainforest mean that data sampling is biased away from the center of the Amazon basin, and both explanations are reasonably well supported by the available data.
+
+More than 56% of the dust fertilizing the Amazon rainforest comes from the Bodélé depression in Northern Chad in the Sahara desert. The dust contains phosphorus, important for plant growth. The yearly Sahara dust replaces the equivalent amount of phosphorus washed away yearly in Amazon soil from rains and floods.[18]
+
+NASA's CALIPSO satellite has measured the amount of dust transported by wind from the Sahara to the Amazon: an average 182 million tons of dust are windblown out of the Sahara each year, at 15 degrees west longitude, across 2,600 km (1,600 mi) over the Atlantic Ocean (some dust falls into the Atlantic), then at 35 degrees West longitude at the eastern coast of South America, 27.7 million tons (15%) of dust fall over the Amazon basin (22 million tons of it consisting of phosphorus), 132 million tons of dust remain in the air, 43 million tons of dust are windblown and falls on the Caribbean Sea, past 75 degrees west longitude.[19]
+
+CALIPSO uses a laser range finder to scan the Earth's atmosphere for the vertical distribution of dust and other aerosols. CALIPSO regularly tracks the Sahara-Amazon dust plume. CALIPSO has measured variations in the dust amounts transported – an 86 percent drop between the highest amount of dust transported in 2007 and the lowest in 2011.
+
+A possibility causing the variation is the Sahel, a strip of semi-arid land on the southern border of the Sahara. When rain amounts in the Sahel are higher, the volume of dust is lower. The higher rainfall could make more vegetation grow in the Sahel, leaving less sand exposed to winds to blow away.[20]
+
+Amazon phosphorus also comes as smoke due to biomass burning in Africa.[21][22]
+
+Based on archaeological evidence from an excavation at Caverna da Pedra Pintada, human inhabitants first settled in the Amazon region at least 11,200 years ago.[24] Subsequent development led to late-prehistoric settlements along the periphery of the forest by AD 1250, which induced alterations in the forest cover.[25]
+
+For a long time, it was thought that the Amazon rainforest was never more than sparsely populated, as it was impossible to sustain a large population through agriculture given the poor soil. Archeologist Betty Meggers was a prominent proponent of this idea, as described in her book Amazonia: Man and Culture in a Counterfeit Paradise. She claimed that a population density of 0.2 inhabitants per square kilometre (0.52/sq mi) is the maximum that can be sustained in the rainforest through hunting, with agriculture needed to host a larger population.[26] However, recent anthropological findings have suggested that the region was actually densely populated. Some 5 million people may have lived in the Amazon region in AD 1500, divided between dense coastal settlements, such as that at Marajó, and inland dwellers.[27] By 1900, the population had fallen to 1 million and by the early 1980s it was less than 200,000.[27]
+
+The first European to travel the length of the Amazon River was Francisco de Orellana in 1542.[28] The BBC's Unnatural Histories presents evidence that Orellana, rather than exaggerating his claims as previously thought, was correct in his observations that a complex civilization was flourishing along the Amazon in the 1540s. It is believed that civilization was later devastated by the spread of diseases from Europe, such as smallpox.[29]. This civilization was investigated by the British explorer Percy Fawcett in the early twentieth century.  The results of his expeditions were inconclusive and he disappeared mysteriously on his last trip.  His name for this lost civilization was the City of Z.
+
+Since the 1970s, numerous geoglyphs have been discovered on deforested land dating between AD 1–1250, furthering claims about Pre-Columbian civilizations.[30][31] Ondemar Dias is accredited with first discovering the geoglyphs in 1977, and Alceu Ranzi is credited with furthering their discovery after flying over Acre.[29][32] The BBC's Unnatural Histories presented evidence that the Amazon rainforest, rather than being a pristine wilderness, has been shaped by man for at least 11,000 years through practices such as forest gardening and terra preta.[29] Terra preta is found over large areas in the Amazon forest; and is now widely accepted as a product of indigenous soil management. The development of this fertile soil allowed agriculture and silviculture in the previously hostile environment; meaning that large portions of the Amazon rainforest are probably the result of centuries of human management, rather than naturally occurring as has previously been supposed.[33] In the region of the Xingu tribe, remains of some of these large settlements in the middle of the Amazon forest were found in 2003 by Michael Heckenberger and colleagues of the University of Florida. Among those were evidence of roads, bridges and large plazas.[34]
+
+Wet tropical forests are the most species-rich biome, and tropical forests in the Americas are consistently more species rich than the wet forests in Africa and Asia.[35] As the largest tract of tropical rainforest in the Americas, the Amazonian rainforests have unparalleled biodiversity. One in ten known species in the world lives in the Amazon rainforest.[36] This constitutes the largest collection of living plants and animal species in the world.
+
+The region is home to about 2.5 million insect species,[37] tens of thousands of plants, and some 2,000 birds and mammals. To date, at least 40,000 plant species, 2,200 fishes,[38] 1,294 birds, 427 mammals, 428 amphibians, and 378 reptiles have been scientifically classified in the region.[39] One in five of all bird species are found in the Amazon rainforest, and one in five of the fish species live in Amazonian rivers and streams. Scientists have described between 96,660 and 128,843 invertebrate species in Brazil alone.[40]
+
+The biodiversity of plant species is the highest on Earth with one 2001 study finding a quarter square kilometer (62 acres) of Ecuadorian rainforest supports more than 1,100 tree species.[41] A study in 1999 found one square kilometer (247 acres) of Amazon rainforest can contain about 90,790 tonnes of living plants. The average plant biomass is estimated at 356 ± 47 tonnes per hectare.[42] To date, an estimated 438,000 species of plants of economic and social interest have been registered in the region with many more remaining to be discovered or catalogued.[43] The total number of tree species in the region is estimated at 16,000.[3]
+
+The green leaf area of plants and trees in the rainforest varies by about 25% as a result of seasonal changes. Leaves expand during the dry season when sunlight is at a maximum, then undergo abscission in the cloudy wet season. These changes provide a balance of carbon between photosynthesis and respiration.[44]
+
+The rainforest contains several species that can pose a hazard. Among the largest predatory creatures are the black caiman, jaguar, cougar, and anaconda. In the river, electric eels can produce an electric shock that can stun or kill, while piranha are known to bite and injure humans.[45] Various species of poison dart frogs secrete lipophilic alkaloid toxins through their flesh. There are also numerous parasites and disease vectors. Vampire bats dwell in the rainforest and can spread the rabies virus.[46] Malaria, yellow fever and dengue fever can also be contracted in the Amazon region.
+
+Hoatzin
+
+Mygalomorphae
+
+Howler monkey
+
+Heliconia
+
+Brown-throated sloth
+
+Emperor tamarin
+
+Blue poison dart frog
+
+South American jaguar
+
+Bald uakari
+
+Bullet ants have an extremely painful sting
+
+Parrots at clay lick in Yasuni National Park, Ecuador
+
+Deforestation is the conversion of forested areas to non-forested areas. The main sources of deforestation in the Amazon are human settlement and development of the land.[47] In 2018, about 17% of the Amazon rainforest was already destroyed. Research suggests that upon reaching about 20–25% (hence 3–8% more), the tipping point to flip it into a non-forest ecosystems – degraded savannah – (in eastern, southern and central Amazonia) will be reached.[48][49]
+
+Prior to the early 1960s, access to the forest's interior was highly restricted, and the forest remained basically intact.[50] Farms established during the 1960s were based on crop cultivation and the slash and burn method. However, the colonists were unable to manage their fields and the crops because of the loss of soil fertility and weed invasion.[51] The soils in the Amazon are productive for just a short period of time, so farmers are constantly moving to new areas and clearing more land.[51] These farming practices led to deforestation and caused extensive environmental damage.[52] Deforestation is considerable, and areas cleared of forest are visible to the naked eye from outer space.
+
+In the 1970s, construction began on the Trans-Amazonian highway. This highway represented a major threat to the Amazon rainforest.[53] The highway still has not been completed, limiting the environmental damage.
+
+Between 1991 and 2000, the total area of forest lost in the Amazon rose from 415,000 to 587,000 km2 (160,000 to 227,000 sq mi), with most of the lost forest becoming pasture for cattle.[54] Seventy percent of formerly forested land in the Amazon, and 91% of land deforested since 1970, have been used for livestock pasture.[55][56] Currently, Brazil is the second-largest global producer of soybeans after the United States. New research however, conducted by Leydimere Oliveira et al., has shown that the more rainforest is logged in the Amazon, the less precipitation reaches the area and so the lower the yield per hectare becomes. So despite the popular perception, there has been no economical advantage for Brazil from logging rainforest zones and converting these to pastoral fields.[57]
+
+The needs of soy farmers have been used to justify many of the controversial transportation projects that are currently developing in the Amazon. The first two highways successfully opened up the rainforest and led to increased settlement and deforestation. The mean annual deforestation rate from 2000 to 2005 (22,392 km2 or 8,646 sq mi per year) was 18% higher than in the previous five years (19,018 km2 or 7,343 sq mi per year).[58] Although deforestation declined significantly in the Brazilian Amazon between 2004 and 2014, there has been an increase to the present day.[59]
+
+Since the discovery of fossil fuel reservoirs in the Amazon rainforest, oil drilling activity has steadily increased, peaking in the Western Amazon in the 1970s and ushering another drilling boom in the 2000s.[60] As oil companies have to set up their operations by opening roads through forests, which often contributes to deforestation in the region.[61]
+
+The European Union–Mercosur free trade agreement, which would form one of the world's largest free trade areas, has been denounced by environmental activists and indigenous rights campaigners.[62] The fear is that the deal could lead to more deforestation of the Amazon rainforest as it expands market access to Brazilian beef.[63]
+
+There have been 72,843 fires in Brazil in 2019, with more than half within the Amazon region.[64][65][66]  In August 2019 there were a record number of fires.[67] Deforestation in the Brazilian Amazon rose more than 88% in June 2019 compared with the same month in 2018.[68]
+
+NASA satellite observation of deforestation in the Mato Grosso state of Brazil. The transformation from forest to farm is evident by the paler square shaped areas under development.
+
+Fires and deforestation in the state of Rondônia
+
+One consequence of forest clearing in the Amazon: thick smoke that hangs over the forest
+
+Impact of deforestation on natural habitat of trees
+
+Environmentalists are concerned about loss of biodiversity that will result from destruction of the forest, and also about the release of the carbon contained within the vegetation, which could accelerate global warming. Amazonian evergreen forests account for about 10% of the world's terrestrial primary productivity and 10% of the carbon stores in ecosystems[69] – of the order of 1.1 × 1011 metric tonnes of carbon.[70] Amazonian forests are estimated to have accumulated 0.62 ± 0.37 tons of carbon per hectare per year between 1975 and 1996.[70]
+
+One computer model of future climate change caused by greenhouse gas emissions shows that the Amazon rainforest could become unsustainable under conditions of severely reduced rainfall and increased temperatures, leading to an almost complete loss of rainforest cover in the basin by 2100.[71][72] However, simulations of Amazon basin climate change across many different models are not consistent in their estimation of any rainfall response, ranging from weak increases to strong decreases.[73] The result indicates that the rainforest could be threatened though the 21st century by climate change in addition to deforestation.
+
+In 1989, environmentalist C.M. Peters and two colleagues stated there is economic as well as biological incentive to protecting the rainforest. One hectare in the Peruvian Amazon has been calculated to have a value of $6820 if intact forest is sustainably harvested for fruits, latex, and timber; $1000 if clear-cut for commercial timber (not sustainably harvested); or $148 if used as cattle pasture.[74]
+
+As indigenous territories continue to be destroyed by deforestation and ecocide, such as in the Peruvian Amazon[75] indigenous peoples' rainforest communities continue to disappear, while others, like the Urarina continue to struggle to fight for their cultural survival and the fate of their forested territories. Meanwhile, the relationship between non-human primates in the subsistence and symbolism of indigenous lowland South American peoples has gained increased attention, as have ethno-biology and community-based conservation efforts.
+
+From 2002 to 2006, the conserved land in the Amazon rainforest almost tripled and deforestation rates dropped up to 60%. About 1,000,000 km2 (250,000,000 acres) have been put onto some sort of conservation, which adds up to a current amount of 1,730,000 km2 (430,000,000 acres).[76]
+
+In April 2019, the Ecuadorian court stopped oil exploration activities in 180,000 hectares (440,000 acres) of the Amazon rainforest.[77]
+
+In July 2019, the Ecuadorian court forbade the government to sell territory with forests to oil companies.[78] In September 2019, the US and Brazil agreed to promote private-sector development in the Amazon. They also pledged a $100m  biodiversity conservation fund for the Amazon led by the private sector. Brazil's foreign minister stated that opening the rain-forest to economic development was the only way to protect it.[79]
+
+Anthropogenic emission of greenhouse gases broken down by sector for the year 2000.
+
+Aerosols over the Amazon each September for four burning seasons (2005 through 2008). The aerosol scale (yellow to dark reddish-brown) indicates the relative amount of particles that absorb sunlight.
+
+Aerial roots of red mangrove on an Amazonian river.
+
+A 2009 study found that a 4 °C rise (above pre-industrial levels) in global temperatures by 2100 would kill 85% of the Amazon rainforest while a temperature rise of 3 °C would kill some 75% of the Amazon.[80]
+
+Deforestation in the Amazon rainforest region has a negative impact on local climate.[81] It was one of the main causes of the severe drought  of 2014–2015 in Brazil.[82][83] This is because the moisture from the forests is important to the rainfall in Brazil, Paraguay and Argentina. Half of the rainfall in the Amazon area is produced by the forests.[84]
+
+The use of remotely sensed data is dramatically improving conservationists' knowledge of the Amazon basin. Given the objectivity and lowered costs of satellite-based land cover analysis, it appears likely that remote sensing technology will be an integral part of assessing the extent and damage of deforestation in the basin.[85] Furthermore, remote sensing is the best and perhaps only possible way to study the Amazon on a large scale.[86]
+
+The use of remote sensing for the conservation of the Amazon is also being used by the indigenous tribes of the basin to protect their tribal lands from commercial interests. Using handheld GPS devices and programs like Google Earth, members of the Trio Tribe, who live in the rainforests of southern Suriname, map out their ancestral lands to help strengthen their territorial claims.[87] Currently, most tribes in the Amazon do not have clearly defined boundaries, making it easier for commercial ventures to target their territories.
+
+To accurately map the Amazon's biomass and subsequent carbon related emissions, the classification of tree growth stages within different parts of the forest is crucial. In 2006, Tatiana Kuplich organized the trees of the Amazon into four categories: mature forest, regenerating forest [less than three years], regenerating forest [between three and five years of regrowth], and regenerating forest [eleven to eighteen years of continued development].[88] The researcher used a combination of synthetic aperture radar (SAR) and Thematic Mapper (TM) to accurately place the different portions of the Amazon into one of the four classifications.
+
+In 2005, parts of the Amazon basin experienced the worst drought in one hundred years,[89] and there were indications that 2006 may have been a second successive year of drought.[90] A 23 July 2006 article in the UK newspaper The Independent reported the Woods Hole Research Center results, showing that the forest in its present form could survive only three years of drought.[91][92] Scientists at the Brazilian National Institute of Amazonian Research argued in the article that this drought response, coupled with the effects of deforestation on regional climate, are pushing the rainforest towards a "tipping point" where it would irreversibly start to die.[93] It concluded that the forest is on the brink of[vague] being turned into savanna or desert, with catastrophic consequences for the world's climate.[citation needed]
+
+According to the World Wide Fund for Nature, the combination of climate change and deforestation increases the drying effect of dead trees that fuels forest fires.[94]
+
+In 2010, the Amazon rainforest experienced another severe drought, in some ways more extreme than the 2005 drought. The affected region was approximately 3,000,000 km2 (1,160,000 sq mi) of rainforest, compared with 1,900,000 km2 (734,000 sq mi) in 2005. The 2010 drought had three epicenters where vegetation died off, whereas in 2005, the drought was focused on the southwestern part. The findings were published in the journal Science. In a typical year, the Amazon absorbs 1.5 gigatons of carbon dioxide; during 2005 instead 5 gigatons were released and in 2010 8 gigatons were released.[95][96] Additional severe droughts occurred in 2010, 2015, and 2016.[97]
+
+In 2019 Brazil's protections of the Amazon rainforest were slashed, resulting in a severe loss of trees.[98] According to Brazil's National Institute for Space Research (INPE), deforestation in the Brazilian Amazon rose more than 50% in the first three months of 2020 compared to the same three-month period in 2019.[99]

en/2038.html.txt

@@ -0,0 +1,133 @@
+
+
+The Amazon rainforest,[a] alternatively, the Amazon Jungle, also known in English as Amazonia, is a moist broadleaf tropical rainforest in the Amazon biome that covers most of the Amazon basin of South America. This basin encompasses 7,000,000 km2 (2,700,000 sq mi), of which 5,500,000 km2 (2,100,000 sq mi) are covered by the rainforest. This region includes territory belonging to nine nations.
+
+The majority of the forest is contained within Brazil, with 60% of the rainforest, followed by Peru with 13%, Colombia with 10%, and with minor amounts in Venezuela, Ecuador, Bolivia, Guyana, Suriname and French Guiana. Four nations have "Amazonas" as the name of one of their first-level administrative regions and France uses the name "Guiana Amazonian Park" for its rainforest protected area. The Amazon represents over half of the planet's remaining rainforests,[2] and comprises the largest and most biodiverse tract of tropical rainforest in the world, with an estimated 390 billion individual trees divided into 16,000 species.[3]
+
+The name Amazon is said to arise from a war Francisco de Orellana fought with the Tapuyas and other tribes. The women of the tribe fought alongside the men, as was their custom.[4] Orellana derived the name Amazonas from the Amazons of Greek mythology, described by Herodotus and Diodorus.[4]
+
+Tribal societies are well capable of escalation to all-out wars between tribes. Thus, in the Amazonas, there was perpetual animosity between the neighboring tribes of the Jivaro. Several tribes of the Jivaroan group, including the Shuar, practised headhunting for trophies and headshrinking.[5] The accounts of missionaries to the area in the borderlands between Brazil and Venezuela have recounted constant infighting in the Yanomami tribes. More than a third of the Yanomamo males, on average, died from warfare.[6]
+
+During the Amazon rubber boom it is estimated that diseases brought by immigrants, such as typhus and malaria, killed 40,000 native Amazonians.[7]
+
+Nine countries share the Amazon basin—most of the rainforest, 58.4%, is contained within the borders of Brazil. The other eight countries include Peru with 12.8%, Bolivia with 7.7%, Colombia with 7.1%, Venezuela with 6.1%, Guyana with 3.1%, Suriname with 2.5%, French Guyana with 1.4%, and Ecuador with 1%.[8]
+
+The rainforest likely formed during the Eocene era (from 56 million years to 33.9 million years ago). It appeared following a global reduction of tropical temperatures when the Atlantic Ocean had widened sufficiently to provide a warm, moist climate to the Amazon basin. The rainforest has been in existence for at least 55 million years, and most of the region remained free of savanna-type biomes at least until the current ice age when the climate was drier and savanna more widespread.[9][10]
+
+Following the Cretaceous–Paleogene extinction event, the extinction of the dinosaurs and the wetter climate may have allowed the tropical rainforest to spread out across the continent. From 66–34 Mya, the rainforest extended as far south as 45°. Climate fluctuations during the last 34 million years have allowed savanna regions to expand into the tropics. During the Oligocene, for example, the rainforest spanned a relatively narrow band. It expanded again during the Middle Miocene, then retracted to a mostly inland formation at the last glacial maximum.[11] However, the rainforest still managed to thrive during these glacial periods, allowing for the survival and evolution of a broad diversity of species.[12]
+
+During the mid-Eocene, it is believed that the drainage basin of the Amazon was split along the middle of the continent by the Purus Arch. Water on the eastern side flowed toward the Atlantic, while to the west water flowed toward the Pacific across the Amazonas Basin. As the Andes Mountains rose, however, a large basin was created that enclosed a lake; now known as the Solimões Basin. Within the last 5–10 million years, this accumulating water broke through the Purus Arch, joining the easterly flow toward the Atlantic.[13][14]
+
+There is evidence that there have been significant changes in the Amazon rainforest vegetation over the last 21,000 years through the last glacial maximum (LGM) and subsequent deglaciation. Analyses of sediment deposits from Amazon basin paleolakes and the Amazon Fan indicate that rainfall in the basin during the LGM was lower than for the present, and this was almost certainly associated with reduced moist tropical vegetation cover in the basin.[15] There is a debate, however, over how extensive this reduction was. Some scientists argue that the rainforest was reduced to small, isolated refugia separated by open forest and grassland;[16] other scientists argue that the rainforest remained largely intact but extended less far to the north, south, and east than is seen today.[17] This debate has proved difficult to resolve because the practical limitations of working in the rainforest mean that data sampling is biased away from the center of the Amazon basin, and both explanations are reasonably well supported by the available data.
+
+More than 56% of the dust fertilizing the Amazon rainforest comes from the Bodélé depression in Northern Chad in the Sahara desert. The dust contains phosphorus, important for plant growth. The yearly Sahara dust replaces the equivalent amount of phosphorus washed away yearly in Amazon soil from rains and floods.[18]
+
+NASA's CALIPSO satellite has measured the amount of dust transported by wind from the Sahara to the Amazon: an average 182 million tons of dust are windblown out of the Sahara each year, at 15 degrees west longitude, across 2,600 km (1,600 mi) over the Atlantic Ocean (some dust falls into the Atlantic), then at 35 degrees West longitude at the eastern coast of South America, 27.7 million tons (15%) of dust fall over the Amazon basin (22 million tons of it consisting of phosphorus), 132 million tons of dust remain in the air, 43 million tons of dust are windblown and falls on the Caribbean Sea, past 75 degrees west longitude.[19]
+
+CALIPSO uses a laser range finder to scan the Earth's atmosphere for the vertical distribution of dust and other aerosols. CALIPSO regularly tracks the Sahara-Amazon dust plume. CALIPSO has measured variations in the dust amounts transported – an 86 percent drop between the highest amount of dust transported in 2007 and the lowest in 2011.
+
+A possibility causing the variation is the Sahel, a strip of semi-arid land on the southern border of the Sahara. When rain amounts in the Sahel are higher, the volume of dust is lower. The higher rainfall could make more vegetation grow in the Sahel, leaving less sand exposed to winds to blow away.[20]
+
+Amazon phosphorus also comes as smoke due to biomass burning in Africa.[21][22]
+
+Based on archaeological evidence from an excavation at Caverna da Pedra Pintada, human inhabitants first settled in the Amazon region at least 11,200 years ago.[24] Subsequent development led to late-prehistoric settlements along the periphery of the forest by AD 1250, which induced alterations in the forest cover.[25]
+
+For a long time, it was thought that the Amazon rainforest was never more than sparsely populated, as it was impossible to sustain a large population through agriculture given the poor soil. Archeologist Betty Meggers was a prominent proponent of this idea, as described in her book Amazonia: Man and Culture in a Counterfeit Paradise. She claimed that a population density of 0.2 inhabitants per square kilometre (0.52/sq mi) is the maximum that can be sustained in the rainforest through hunting, with agriculture needed to host a larger population.[26] However, recent anthropological findings have suggested that the region was actually densely populated. Some 5 million people may have lived in the Amazon region in AD 1500, divided between dense coastal settlements, such as that at Marajó, and inland dwellers.[27] By 1900, the population had fallen to 1 million and by the early 1980s it was less than 200,000.[27]
+
+The first European to travel the length of the Amazon River was Francisco de Orellana in 1542.[28] The BBC's Unnatural Histories presents evidence that Orellana, rather than exaggerating his claims as previously thought, was correct in his observations that a complex civilization was flourishing along the Amazon in the 1540s. It is believed that civilization was later devastated by the spread of diseases from Europe, such as smallpox.[29]. This civilization was investigated by the British explorer Percy Fawcett in the early twentieth century.  The results of his expeditions were inconclusive and he disappeared mysteriously on his last trip.  His name for this lost civilization was the City of Z.
+
+Since the 1970s, numerous geoglyphs have been discovered on deforested land dating between AD 1–1250, furthering claims about Pre-Columbian civilizations.[30][31] Ondemar Dias is accredited with first discovering the geoglyphs in 1977, and Alceu Ranzi is credited with furthering their discovery after flying over Acre.[29][32] The BBC's Unnatural Histories presented evidence that the Amazon rainforest, rather than being a pristine wilderness, has been shaped by man for at least 11,000 years through practices such as forest gardening and terra preta.[29] Terra preta is found over large areas in the Amazon forest; and is now widely accepted as a product of indigenous soil management. The development of this fertile soil allowed agriculture and silviculture in the previously hostile environment; meaning that large portions of the Amazon rainforest are probably the result of centuries of human management, rather than naturally occurring as has previously been supposed.[33] In the region of the Xingu tribe, remains of some of these large settlements in the middle of the Amazon forest were found in 2003 by Michael Heckenberger and colleagues of the University of Florida. Among those were evidence of roads, bridges and large plazas.[34]
+
+Wet tropical forests are the most species-rich biome, and tropical forests in the Americas are consistently more species rich than the wet forests in Africa and Asia.[35] As the largest tract of tropical rainforest in the Americas, the Amazonian rainforests have unparalleled biodiversity. One in ten known species in the world lives in the Amazon rainforest.[36] This constitutes the largest collection of living plants and animal species in the world.
+
+The region is home to about 2.5 million insect species,[37] tens of thousands of plants, and some 2,000 birds and mammals. To date, at least 40,000 plant species, 2,200 fishes,[38] 1,294 birds, 427 mammals, 428 amphibians, and 378 reptiles have been scientifically classified in the region.[39] One in five of all bird species are found in the Amazon rainforest, and one in five of the fish species live in Amazonian rivers and streams. Scientists have described between 96,660 and 128,843 invertebrate species in Brazil alone.[40]
+
+The biodiversity of plant species is the highest on Earth with one 2001 study finding a quarter square kilometer (62 acres) of Ecuadorian rainforest supports more than 1,100 tree species.[41] A study in 1999 found one square kilometer (247 acres) of Amazon rainforest can contain about 90,790 tonnes of living plants. The average plant biomass is estimated at 356 ± 47 tonnes per hectare.[42] To date, an estimated 438,000 species of plants of economic and social interest have been registered in the region with many more remaining to be discovered or catalogued.[43] The total number of tree species in the region is estimated at 16,000.[3]
+
+The green leaf area of plants and trees in the rainforest varies by about 25% as a result of seasonal changes. Leaves expand during the dry season when sunlight is at a maximum, then undergo abscission in the cloudy wet season. These changes provide a balance of carbon between photosynthesis and respiration.[44]
+
+The rainforest contains several species that can pose a hazard. Among the largest predatory creatures are the black caiman, jaguar, cougar, and anaconda. In the river, electric eels can produce an electric shock that can stun or kill, while piranha are known to bite and injure humans.[45] Various species of poison dart frogs secrete lipophilic alkaloid toxins through their flesh. There are also numerous parasites and disease vectors. Vampire bats dwell in the rainforest and can spread the rabies virus.[46] Malaria, yellow fever and dengue fever can also be contracted in the Amazon region.
+
+Hoatzin
+
+Mygalomorphae
+
+Howler monkey
+
+Heliconia
+
+Brown-throated sloth
+
+Emperor tamarin
+
+Blue poison dart frog
+
+South American jaguar
+
+Bald uakari
+
+Bullet ants have an extremely painful sting
+
+Parrots at clay lick in Yasuni National Park, Ecuador
+
+Deforestation is the conversion of forested areas to non-forested areas. The main sources of deforestation in the Amazon are human settlement and development of the land.[47] In 2018, about 17% of the Amazon rainforest was already destroyed. Research suggests that upon reaching about 20–25% (hence 3–8% more), the tipping point to flip it into a non-forest ecosystems – degraded savannah – (in eastern, southern and central Amazonia) will be reached.[48][49]
+
+Prior to the early 1960s, access to the forest's interior was highly restricted, and the forest remained basically intact.[50] Farms established during the 1960s were based on crop cultivation and the slash and burn method. However, the colonists were unable to manage their fields and the crops because of the loss of soil fertility and weed invasion.[51] The soils in the Amazon are productive for just a short period of time, so farmers are constantly moving to new areas and clearing more land.[51] These farming practices led to deforestation and caused extensive environmental damage.[52] Deforestation is considerable, and areas cleared of forest are visible to the naked eye from outer space.
+
+In the 1970s, construction began on the Trans-Amazonian highway. This highway represented a major threat to the Amazon rainforest.[53] The highway still has not been completed, limiting the environmental damage.
+
+Between 1991 and 2000, the total area of forest lost in the Amazon rose from 415,000 to 587,000 km2 (160,000 to 227,000 sq mi), with most of the lost forest becoming pasture for cattle.[54] Seventy percent of formerly forested land in the Amazon, and 91% of land deforested since 1970, have been used for livestock pasture.[55][56] Currently, Brazil is the second-largest global producer of soybeans after the United States. New research however, conducted by Leydimere Oliveira et al., has shown that the more rainforest is logged in the Amazon, the less precipitation reaches the area and so the lower the yield per hectare becomes. So despite the popular perception, there has been no economical advantage for Brazil from logging rainforest zones and converting these to pastoral fields.[57]
+
+The needs of soy farmers have been used to justify many of the controversial transportation projects that are currently developing in the Amazon. The first two highways successfully opened up the rainforest and led to increased settlement and deforestation. The mean annual deforestation rate from 2000 to 2005 (22,392 km2 or 8,646 sq mi per year) was 18% higher than in the previous five years (19,018 km2 or 7,343 sq mi per year).[58] Although deforestation declined significantly in the Brazilian Amazon between 2004 and 2014, there has been an increase to the present day.[59]
+
+Since the discovery of fossil fuel reservoirs in the Amazon rainforest, oil drilling activity has steadily increased, peaking in the Western Amazon in the 1970s and ushering another drilling boom in the 2000s.[60] As oil companies have to set up their operations by opening roads through forests, which often contributes to deforestation in the region.[61]
+
+The European Union–Mercosur free trade agreement, which would form one of the world's largest free trade areas, has been denounced by environmental activists and indigenous rights campaigners.[62] The fear is that the deal could lead to more deforestation of the Amazon rainforest as it expands market access to Brazilian beef.[63]
+
+There have been 72,843 fires in Brazil in 2019, with more than half within the Amazon region.[64][65][66]  In August 2019 there were a record number of fires.[67] Deforestation in the Brazilian Amazon rose more than 88% in June 2019 compared with the same month in 2018.[68]
+
+NASA satellite observation of deforestation in the Mato Grosso state of Brazil. The transformation from forest to farm is evident by the paler square shaped areas under development.
+
+Fires and deforestation in the state of Rondônia
+
+One consequence of forest clearing in the Amazon: thick smoke that hangs over the forest
+
+Impact of deforestation on natural habitat of trees
+
+Environmentalists are concerned about loss of biodiversity that will result from destruction of the forest, and also about the release of the carbon contained within the vegetation, which could accelerate global warming. Amazonian evergreen forests account for about 10% of the world's terrestrial primary productivity and 10% of the carbon stores in ecosystems[69] – of the order of 1.1 × 1011 metric tonnes of carbon.[70] Amazonian forests are estimated to have accumulated 0.62 ± 0.37 tons of carbon per hectare per year between 1975 and 1996.[70]
+
+One computer model of future climate change caused by greenhouse gas emissions shows that the Amazon rainforest could become unsustainable under conditions of severely reduced rainfall and increased temperatures, leading to an almost complete loss of rainforest cover in the basin by 2100.[71][72] However, simulations of Amazon basin climate change across many different models are not consistent in their estimation of any rainfall response, ranging from weak increases to strong decreases.[73] The result indicates that the rainforest could be threatened though the 21st century by climate change in addition to deforestation.
+
+In 1989, environmentalist C.M. Peters and two colleagues stated there is economic as well as biological incentive to protecting the rainforest. One hectare in the Peruvian Amazon has been calculated to have a value of $6820 if intact forest is sustainably harvested for fruits, latex, and timber; $1000 if clear-cut for commercial timber (not sustainably harvested); or $148 if used as cattle pasture.[74]
+
+As indigenous territories continue to be destroyed by deforestation and ecocide, such as in the Peruvian Amazon[75] indigenous peoples' rainforest communities continue to disappear, while others, like the Urarina continue to struggle to fight for their cultural survival and the fate of their forested territories. Meanwhile, the relationship between non-human primates in the subsistence and symbolism of indigenous lowland South American peoples has gained increased attention, as have ethno-biology and community-based conservation efforts.
+
+From 2002 to 2006, the conserved land in the Amazon rainforest almost tripled and deforestation rates dropped up to 60%. About 1,000,000 km2 (250,000,000 acres) have been put onto some sort of conservation, which adds up to a current amount of 1,730,000 km2 (430,000,000 acres).[76]
+
+In April 2019, the Ecuadorian court stopped oil exploration activities in 180,000 hectares (440,000 acres) of the Amazon rainforest.[77]
+
+In July 2019, the Ecuadorian court forbade the government to sell territory with forests to oil companies.[78] In September 2019, the US and Brazil agreed to promote private-sector development in the Amazon. They also pledged a $100m  biodiversity conservation fund for the Amazon led by the private sector. Brazil's foreign minister stated that opening the rain-forest to economic development was the only way to protect it.[79]
+
+Anthropogenic emission of greenhouse gases broken down by sector for the year 2000.
+
+Aerosols over the Amazon each September for four burning seasons (2005 through 2008). The aerosol scale (yellow to dark reddish-brown) indicates the relative amount of particles that absorb sunlight.
+
+Aerial roots of red mangrove on an Amazonian river.
+
+A 2009 study found that a 4 °C rise (above pre-industrial levels) in global temperatures by 2100 would kill 85% of the Amazon rainforest while a temperature rise of 3 °C would kill some 75% of the Amazon.[80]
+
+Deforestation in the Amazon rainforest region has a negative impact on local climate.[81] It was one of the main causes of the severe drought  of 2014–2015 in Brazil.[82][83] This is because the moisture from the forests is important to the rainfall in Brazil, Paraguay and Argentina. Half of the rainfall in the Amazon area is produced by the forests.[84]
+
+The use of remotely sensed data is dramatically improving conservationists' knowledge of the Amazon basin. Given the objectivity and lowered costs of satellite-based land cover analysis, it appears likely that remote sensing technology will be an integral part of assessing the extent and damage of deforestation in the basin.[85] Furthermore, remote sensing is the best and perhaps only possible way to study the Amazon on a large scale.[86]
+
+The use of remote sensing for the conservation of the Amazon is also being used by the indigenous tribes of the basin to protect their tribal lands from commercial interests. Using handheld GPS devices and programs like Google Earth, members of the Trio Tribe, who live in the rainforests of southern Suriname, map out their ancestral lands to help strengthen their territorial claims.[87] Currently, most tribes in the Amazon do not have clearly defined boundaries, making it easier for commercial ventures to target their territories.
+
+To accurately map the Amazon's biomass and subsequent carbon related emissions, the classification of tree growth stages within different parts of the forest is crucial. In 2006, Tatiana Kuplich organized the trees of the Amazon into four categories: mature forest, regenerating forest [less than three years], regenerating forest [between three and five years of regrowth], and regenerating forest [eleven to eighteen years of continued development].[88] The researcher used a combination of synthetic aperture radar (SAR) and Thematic Mapper (TM) to accurately place the different portions of the Amazon into one of the four classifications.
+
+In 2005, parts of the Amazon basin experienced the worst drought in one hundred years,[89] and there were indications that 2006 may have been a second successive year of drought.[90] A 23 July 2006 article in the UK newspaper The Independent reported the Woods Hole Research Center results, showing that the forest in its present form could survive only three years of drought.[91][92] Scientists at the Brazilian National Institute of Amazonian Research argued in the article that this drought response, coupled with the effects of deforestation on regional climate, are pushing the rainforest towards a "tipping point" where it would irreversibly start to die.[93] It concluded that the forest is on the brink of[vague] being turned into savanna or desert, with catastrophic consequences for the world's climate.[citation needed]
+
+According to the World Wide Fund for Nature, the combination of climate change and deforestation increases the drying effect of dead trees that fuels forest fires.[94]
+
+In 2010, the Amazon rainforest experienced another severe drought, in some ways more extreme than the 2005 drought. The affected region was approximately 3,000,000 km2 (1,160,000 sq mi) of rainforest, compared with 1,900,000 km2 (734,000 sq mi) in 2005. The 2010 drought had three epicenters where vegetation died off, whereas in 2005, the drought was focused on the southwestern part. The findings were published in the journal Science. In a typical year, the Amazon absorbs 1.5 gigatons of carbon dioxide; during 2005 instead 5 gigatons were released and in 2010 8 gigatons were released.[95][96] Additional severe droughts occurred in 2010, 2015, and 2016.[97]
+
+In 2019 Brazil's protections of the Amazon rainforest were slashed, resulting in a severe loss of trees.[98] According to Brazil's National Institute for Space Research (INPE), deforestation in the Brazilian Amazon rose more than 50% in the first three months of 2020 compared to the same three-month period in 2019.[99]

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+Tropical rainforests are rainforests that occur in areas of tropical rainforest climate in which there is no dry season – all months have an average precipitation of at least 60 mm – and may also be referred to as lowland equatorial evergreen rainforest. True rainforests are typically found between 10 degrees north and south of the equator (see map); they are a sub-set of the tropical forest biome that occurs roughly within the 28-degree latitudes (in the equatorial zone between the Tropic of Cancer and Tropic of Capricorn). Within the World Wildlife Fund's biome classification, tropical rainforests are a type of tropical moist broadleaf forest (or tropical wet forest) that also includes the more extensive seasonal tropical forests.[3]
+
+Tropical rainforests can be characterized in two words: hot and wet. Mean monthly temperatures exceed 18 °C (64 °F) during all months of the year.[4] Average annual rainfall is no less than 1,680 mm (66 in) and can exceed 10 m (390 in) although it typically lies between 1,750 mm (69 in) and 3,000 mm (120 in).[5] This high level of precipitation often results in poor soils due to leaching of soluble nutrients in the ground.
+
+Tropical rainforests exhibit high levels of biodiversity. Around 40% to 75% of all biotic species are indigenous to the rainforests.[6] Rainforests are home to half of all the living animal and plant species on the planet.[7] Two-thirds of all flowering plants can be found in rainforests.[5] A single hectare of rainforest may contain 42,000 different species of insect, up to 807 trees of 313 species and 1,500 species of higher plants.[5] Tropical rainforests have been called the "world's largest pharmacy", because over one quarter of natural medicines have been discovered within them.[8][9] It is likely that there may be many millions of species of plants, insects and microorganisms still undiscovered in tropical rainforests.
+
+Tropical rainforests are among the most threatened ecosystems globally due to large-scale fragmentation as a result of human activity. Habitat fragmentation caused by geological processes such as volcanism and climate change occurred in the past, and have been identified as important drivers of speciation.[10] However, fast human driven habitat destruction is suspected to be one of the major causes of species extinction.  Tropical rain forests have been subjected to heavy logging and agricultural clearance throughout the 20th century, and the area covered by rainforests around the world is rapidly shrinking.[11][12]
+
+Tropical rainforests have existed on earth for hundreds of millions of years. Most tropical rainforests today are on fragments of the Mesozoic era supercontinent of Gondwana.[13] The separation of the landmass resulted in a great loss of amphibian diversity while at the same time the drier climate spurred the diversification of reptiles.[10] The division left tropical rainforests located in five major regions of the world: tropical America, Africa, Southeast Asia, Madagascar, and New Guinea, with smaller outliers in Australia.[13] However, the specifics of the origin of rainforests remain uncertain due to an incomplete fossil record.
+
+Several biomes may appear similar-to, or merge via ecotones with, tropical rainforest:
+
+Moist seasonal tropical forests receive high overall rainfall with a warm summer wet season and a cooler winter dry season. Some trees in these forests drop some or all of their leaves during the winter dry season, thus they are sometimes called "tropical mixed forest". They are found in parts of South America, in Central America and around the Caribbean, in coastal West Africa, parts of the Indian subcontinent, and across much of Indochina.
+
+These are found in cooler-climate mountainous areas, becoming known as cloud forests at higher elevations. Depending on latitude, the lower limit of montane rainforests on large mountains is generally between 1500 and 2500 m while the upper limit is usually from 2400 to 3300 m.[14]
+
+Tropical freshwater swamp forests, or "flooded forests", are found in Amazon basin (the Várzea) and elsewhere.
+
+Rainforests are divided into different strata, or layers, with vegetation organized into a vertical pattern from the top of the soil to the canopy.[15] Each layer is a unique biotic community containing different plants and animals adapted for life in that particular strata. Only the emergent layer is unique to tropical rainforests, while the others are also found in temperate rainforests.
+
+The forest floor, the bottom-most layer, receives only 2% of the sunlight. Only plants adapted to low light can grow in this region. Away from riverbanks, swamps and clearings, where dense undergrowth is found, the forest floor is relatively clear of vegetation because of the low sunlight penetration. This more open quality permits the easy movement of larger animals such as: ungulates like the okapi (Okapia johnstoni), tapir (Tapirus sp.), Sumatran rhinoceros (Dicerorhinus sumatrensis), and apes like the western lowland gorilla (Gorilla gorilla), as well as many species of reptiles, amphibians, and insects.  The forest floor also contains decaying plant and animal matter, which disappears quickly, because the warm, humid conditions promote rapid decay. Many forms of fungi growing here help decay the animal and plant waste.
+
+The understory layer lies between the canopy and the forest floor. The understory is home to a number of birds, small mammals, insects, reptiles, and predators.  Examples include leopard (Panthera pardus), poison dart frogs (Dendrobates sp.), ring-tailed coati (Nasua nasua), boa constrictor (Boa constrictor), and many species of Coleoptera.[5] The vegetation at this layer generally consists of shade-tolerant shrubs, herbs, small trees, and large woody vines which climb into the trees to capture sunlight. Only about 5% of sunlight breaches the canopy to arrive at the understory causing true understory plants to seldom grow to 3 m (10 feet). As an adaptation to these low light levels, understory plants have often evolved much larger leaves. Many seedlings that will grow to the canopy level are in the understory.
+
+The canopy is the primary layer of the forest forming a roof over the two remaining layers. It contains the majority of the largest trees, typically 30–45 m in height. Tall, broad-leaved evergreen trees are the dominant plants.  The densest areas of biodiversity are found in the forest canopy, as it often supports a rich flora of epiphytes, including orchids, bromeliads, mosses and lichens.  These epiphytic plants attach to trunks and branches and obtain water and minerals from rain and debris that collects on the supporting plants. The fauna is similar to that found in the emergent layer, but more diverse. It is suggested that the total arthropod species richness of the tropical canopy might be as high as 20 million.[16] Other species habituating this layer include many avian species such as the yellow-casqued wattled hornbill (Ceratogymna elata), collared sunbird (Anthreptes collaris), grey parrot (Psitacus erithacus), keel-billed toucan (Ramphastos sulfuratus), scarlet macaw (Ara macao) as well as other animals like the spider monkey (Ateles sp.), African giant swallowtail (Papilio antimachus), three-toed sloth (Bradypus tridactylus), kinkajou (Potos flavus), and tamandua (Tamandua tetradactyla).[5]
+
+The emergent layer contains a small number of very large trees, called emergents, which grow above the general canopy, reaching heights of 45–55 m, although on occasion a few species will grow to 70–80 m tall.[15][17] Some examples of emergents include: Balizia elegans, Dipteryx panamensis, Hieronyma alchorneoides, Hymenolobium mesoamericanum, Lecythis ampla and Terminalia oblonga.[18] These trees need to be able to withstand the hot temperatures and strong winds that occur above the canopy in some areas. Several unique faunal species inhabit this layer such as the crowned eagle (Stephanoaetus coronatus), the king colobus (Colobus polykomos), and the large flying fox (Pteropus vampyrus).[5]
+
+However, stratification is not always clear. Rainforests are dynamic and many changes affect the structure of the forest. Emergent or canopy trees collapse, for example, causing gaps to form. Openings in the forest canopy are widely recognized as important for the establishment and growth of rainforest trees.  It is estimated that perhaps 75% of the tree species at La Selva Biological Station, Costa Rica are dependent on canopy opening for seed germination or for growth beyond sapling size, for example.[19]
+
+Tropical rainforests are located around and near the equator, therefore having what is called an equatorial climate characterized by three major climatic parameters: temperature, rainfall, and dry season intensity.[20] Other parameters that affect tropical rainforests are carbon dioxide concentrations, solar radiation, and nitrogen availability. In general, climatic patterns consist of warm temperatures and high annual rainfall. However, the abundance of rainfall changes throughout the year creating distinct moist and dry seasons. Tropical forests are classified by the amount of rainfall received each year, which has allowed ecologists to define differences in these forests that look so similar in structure.  According to Holdridge's classification of tropical ecosystems, true tropical rainforests have an annual rainfall greater than 2 m and annual temperature greater than 24 degrees Celsius, with a potential evapotranspiration ratio (PET) value of <0.25.  However, most lowland tropical forests can be classified as tropical moist or wet forests, which differ in regards to rainfall. Tropical forest ecology- dynamics, composition, and function- are sensitive to changes in climate especially changes in rainfall.[20]
+
+Soil types are highly variable in the tropics and are the result of a combination of several variables such as climate, vegetation, topographic position, parent material, and soil age.[21] Most tropical soils are characterized by significant leaching and poor nutrients, however there are some areas that contain fertile soils. Soils throughout the tropical rainforests fall into two classifications which include the ultisols and oxisols. Ultisols are known as well weathered, acidic red clay soils, deficient in major nutrients such as calcium and potassium. Similarly, oxisols are acidic, old, typically reddish, highly weathered and leached, however are well drained compared to ultisols. The clay content of ultisols is high, making it difficult for water to penetrate and flow through. The reddish color of both soils is the result of heavy heat and moisture forming oxides of iron and aluminium, which are insoluble in water and not taken up readily by plants.
+
+Soil chemical and physical characteristics are strongly related to above ground productivity and forest structure and dynamics. The physical properties of soil control the tree turnover rates whereas chemical properties such as available nitrogen and phosphorus control forest growth rates.[22] The soils of the eastern and central Amazon as well as the Southeast Asian Rainforest are old and mineral poor whereas the soils of the western Amazon (Ecuador and Peru) and volcanic areas of Costa Rica are young and mineral rich. Primary productivity or wood production is highest in western Amazon and lowest in eastern Amazon which contains heavily weathered soils classified as oxisols.[21] Additionally, Amazonian soils are greatly weathered, making them devoid of minerals like phosphorus, potassium, calcium, and magnesium, which come from rock sources. However, not all tropical rainforests occur on nutrient poor soils, but on nutrient rich floodplains and volcanic soils located in the Andean foothills, and volcanic areas of Southeast Asia, Africa, and Central America.[23]
+
+Oxisols, infertile, deeply weathered and severely leached, have developed on the ancient Gondwanan shields. Rapid bacterial decay prevents the accumulation of humus. The concentration of iron and aluminium oxides by the laterization process gives the oxisols a bright red color and sometimes produces minable deposits (e.g., bauxite). On younger substrates, especially of volcanic origin, tropical soils may be quite fertile.
+
+This high rate of decomposition is the result of phosphorus levels in the soils, precipitation, high temperatures and the extensive microorganism communities.[24] In addition to the bacteria and other microorganisms, there are an abundance of other decomposers such as fungi and termites that aid in the process as well. Nutrient recycling is important because below ground resource availability controls the above ground biomass and community structure of tropical rainforests. These soils are typically phosphorus limited, which inhibits net primary productivity or the uptake of carbon.[21] The soil contains microbial organisms such as bacteria, which break down leaf litter and other organic matter into inorganic forms of carbon usable by plants through a process called decomposition. During the decomposition process the microbial community is respiring, taking up oxygen and releasing carbon dioxide. The decomposition rate can be evaluated by measuring the uptake of oxygen.[24] High temperatures and precipitation increase decomposition rate, which allows plant litter to rapidly decay in tropical regions, releasing nutrients that are immediately taken up by plants through surface or ground waters.  The seasonal patterns in respiration are controlled by leaf litter fall and precipitation, the driving force moving the decomposable carbon from the litter to the soil. Respiration rates are highest early in the wet season because the recent dry season results in a large percentage of leaf litter and thus a higher percentage of organic matter being leached into the soil.[24]
+
+A common feature of many tropical rainforests is the distinct buttress roots of trees.  Instead of penetrating to deeper soil layers, buttress roots create a widespread root network at the surface for more efficient uptake of nutrients in a very nutrient poor and competitive environment. Most of the nutrients within the soil of a tropical rainforest occur near the surface because of the rapid turnover time and decomposition of organisms and leaves.[25] Because of this, the buttress roots occur at the surface so the trees can maximize uptake and actively compete with the rapid uptake of other trees. These roots also aid in water uptake and storage, increase surface area for gas exchange, and collect leaf litter for added nutrition.[25] Additionally, these roots reduce soil erosion and maximize nutrient acquisition during heavy rains by diverting nutrient rich water flowing down the trunk into several smaller flows while also acting as a barrier to ground flow. Also, the large surface areas these roots create provide support and stability to rainforests trees, which commonly grow to significant heights. This added stability allows these trees to withstand the impacts of severe storms, thus reducing the occurrence of fallen trees.[25]
+
+Succession is an ecological process that changes the biotic community structure over time towards a more stable, diverse community structure after an initial disturbance to the community. The initial disturbance is often a natural phenomenon or human caused event. Natural disturbances include hurricanes, volcanic eruptions, river movements or an event as small as a fallen tree that creates gaps in the forest. In tropical rainforests, these same natural disturbances have been well documented in the fossil record, and are credited with encouraging speciation and endemism.[10] Human land use practices have led to large-scale deforestation. In many tropical countries such as Costa Rica these deforested lands have been abandoned and forests have been allowed to regenerate through ecological succession. These regenerating young successional forests are called secondary forests or second-growth forests.
+
+Tropical rainforests exhibit a vast diversity in plant and animal species. The root for this remarkable speciation has been a query of scientists and ecologists for years. A number of theories have been developed for why and how the tropics can be so diverse.
+
+Interspecific competition results from a high density of species with similar niches in the tropics and limited resources available. Species which "lose" the competition may either become extinct or find a new niche. Direct competition will often lead to one species dominating another by some advantage, ultimately driving it to extinction. Niche partitioning is the other option for a species. This is the separation and rationing of necessary resources by utilizing different habitats, food sources, cover or general behavioral differences. A species with similar food items but different feeding times is an example of niche partitioning.[26]
+
+The theory of Pleistocene refugia was developed by Jürgen Haffer in 1969 with his article Speciation of Amazonian Forest Birds. Haffer proposed the explanation for speciation was the product of rainforest patches being separated by stretches of non-forest vegetation during the last glacial period.  He called these patches of rainforest areas refuges and within these patches allopatric speciation occurred. With the end of the glacial period and increase in atmospheric humidity, rainforest began to expand and the refuges reconnected.[27] This theory has been the subject of debate. Scientists are still skeptical of whether or not this theory is legitimate. Genetic evidence suggests speciation had occurred in certain taxa 1–2 million years ago, preceding the Pleistocene.[28]
+
+Tropical rainforests have harboured human life for many millennia, with many Indian tribes in South- and Central America, who belong to the Indigenous peoples of the Americas, the Congo Pygmies in Central Africa, and several tribes in South-East Asia, like the Dayak people and the Penan people in Borneo.[29] Food resources within the forest are extremely dispersed due to the high biological diversity and what food does exist is largely restricted to the canopy and requires considerable energy to obtain. Some groups of hunter-gatherers have exploited rainforest on a seasonal basis but dwelt primarily in adjacent savanna and open forest environments where food is much more abundant. Other people described as rainforest dwellers are hunter-gatherers who subsist in large part by trading high value forest products such as hides, feathers, and honey with agricultural people living outside the forest.[30]
+
+A variety of indigenous people live within the rainforest as hunter-gatherers, or subsist as part-time small scale farmers supplemented in large part by trading high-value forest products such as hides, feathers, and honey with agricultural people living outside the forest.[29][30] Peoples have inhabited the rainforests for tens of thousands of years and have remained so elusive that only recently have some tribes been discovered.[29] These indigenous peoples are greatly threatened by loggers in search for old-growth tropical hardwoods like Ipe, Cumaru and Wenge, and by farmers who are looking to expand their land, for cattle(meat), and soybeans, which are used to feed cattle in Europe and China.[29][31][32][33] On 18 January 2007, FUNAI reported also that it had confirmed the presence of 67 different uncontacted tribes in Brazil, up from 40 in 2005. With this addition, Brazil has now overtaken the island of New Guinea as the country having the largest number of uncontacted tribes.[34] The province of Irian Jaya or West Papua in the island of New Guinea is home to an estimated 44 uncontacted tribal groups.[35]
+
+The pygmy peoples are hunter-gatherer groups living in equatorial rainforests characterized by their short height (below one and a half meters, or 59 inches, on average). Amongst this group are the Efe, Aka, Twa, Baka, and Mbuti people of Central Africa.[36] However, the term pygmy is considered pejorative so many tribes prefer not to be labeled as such.[37]
+
+Some notable indigenous peoples of the Americas, or Amerindians, include the Huaorani, Ya̧nomamö, and Kayapo people of the Amazon. The traditional agricultural system practiced by tribes in the Amazon is based on swidden cultivation (also known as slash-and-burn or shifting cultivation) and is considered a relatively benign disturbance.[38][39] In fact, when looking at the level of individual swidden plots a number of traditional farming practices are considered beneficial. For example, the use of shade trees and fallowing all help preserve soil organic matter, which is a critical factor in the maintenance of soil fertility in the deeply weathered and leached soils common in the Amazon.[40]
+
+There is a diversity of forest people in Asia, including the Lumad peoples of the Philippines and the Penan and Dayak people of Borneo. The Dayaks are a particularly interesting group as they are noted for their traditional headhunting culture.  Fresh human heads were required to perform certain rituals such as the Iban "kenyalang" and the Kenyah "mamat".[41] Pygmies who live in Southeast Asia are, amongst others, referred to as "Negrito".
+
+Yam, coffee, chocolate, banana, mango, papaya, macadamia, avocado, and sugarcane all originally came from tropical rainforest and are still mostly grown on plantations in regions that were formerly primary forest. In the mid-1980s and 1990s, 40 million tons of bananas were consumed worldwide each year, along with 13 million tons of mango. Central American coffee exports were worth US$3 billion in 1970.  Much of the genetic variation used in evading the damage caused by new pests is still derived from resistant wild stock. Tropical forests have supplied 250 cultivated kinds of fruit, compared to only 20 for temperate forests. Forests in New Guinea alone contain 251 tree species with edible fruits, of which only 43 had been established as cultivated crops by 1985.[42]
+
+In addition to extractive human uses, rain forests also have non-extractive uses that are frequently summarized as ecosystem services. Rain forests play an important role in maintaining biological diversity, sequestering and storing carbon, global climate regulation, disease control, and pollination.[43] Half of the rainfall in the Amazon area is produced by the forests. The moisture from the forests is important to the rainfall in Brazil, Paraguay, Argentina[44] Deforestation in the Amazon rainforest region was one of the main reason that cause the severe Drought of 2014-2015 in Brazil[45][46] For the last three decades, the amount of carbon absorbed by the world’s intact tropical forests has fallen, according to a study published in 2020 in the journal Nature. In 2019 they took up a third less carbon than they did in the 1990s, due to higher temperatures, droughts and deforestation. The typical tropical forest may become a carbon source by the 2060s.[47]
+
+Despite the negative effects of tourism in the tropical rainforests, there are also several important positive effects.
+
+Deposits of precious metals (gold, silver, coltan) and fossil fuels (oil and natural gas) occur underneath rainforests globally.  These resources are important to developing nations and their extraction is often given priority to encourage economic growth.  Mining and drilling can require large amounts of land development, directly causing deforestation.  In Ghana, a West African nation, deforestation from decades of mining activity left about 12% of the country's original rainforest intact.[50]
+
+With the invention of agriculture, humans were able to clear sections of rainforest to produce crops, converting it to open farmland. Such people, however, obtain their food primarily from farm plots cleared from the forest[30][51] and hunt and forage within the forest to supplement this. The issue arising is between the independent farmer providing for his family and the needs and wants of the globe as a whole. This issue has seen little improvement because no plan has been established for all parties to be aided.[52]
+
+Agriculture on formerly forested land is not without difficulties. Rainforest soils are often thin and leached of many minerals, and the heavy rainfall can quickly leach nutrients from area cleared for cultivation. People such as the Yanomamo of the Amazon, utilize slash-and-burn agriculture to overcome these limitations and enable them to push deep into what were previously rainforest environments. However, these are not rainforest dwellers, rather they are dwellers in cleared farmland[30][51] that make forays into the rainforest. Up to 90% of the typical Yanamomo diet comes from farmed plants.[51]
+
+Some action has been taken by suggesting fallow periods of the land allowing secondary forest to grow and replenish the soil.[53] Beneficial practices like soil restoration and conservation can benefit the small farmer and allow better production on smaller parcels of land.
+
+The tropics take a major role in reducing atmospheric carbon dioxide. The tropics (most notably the Amazon rainforest) are called carbon sinks.[citation needed] As major carbon reducers and carbon and soil methane storages, their destruction contributes to increasing global energy trapping, atmospheric gases.[citation needed] Climate change has been significantly contributed to by the destruction of the rainforests. A simulation was performed in which all rainforest in Africa were removed. The simulation showed an increase in atmospheric temperature by 2.5 to 5 degrees Celsius.[54]
+
+Efforts to protect and conserve tropical rainforest habitats are diverse and widespread.  Tropical rainforest conservation ranges from strict preservation of habitat to finding sustainable management techniques for people living in tropical rainforests.  International policy has also introduced a market incentive program called Reducing Emissions from Deforestation and Forest Degradation (REDD) for companies and governments to outset their carbon emissions through financial investments into rainforest conservation.[55]

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+Amphibians are ectothermic, tetrapod vertebrates of the class Amphibia. Modern amphibians are all Lissamphibia. They inhabit a wide variety of habitats, with most species living within terrestrial, fossorial, arboreal or freshwater aquatic ecosystems. Thus amphibians typically start out as larvae living in water, but some species have developed behavioural adaptations to bypass this.
+
+The young generally undergo metamorphosis from larva with gills to an adult air-breathing form with lungs. Amphibians use their skin as a secondary respiratory surface and some small terrestrial salamanders and frogs lack lungs and rely entirely on their skin. They are superficially similar to lizards but, along with mammals and birds, reptiles are amniotes and do not require water bodies in which to breed. With their complex reproductive needs and permeable skins, amphibians are often ecological indicators; in recent decades there has been a dramatic decline in amphibian populations for many species around the globe.
+
+The earliest amphibians evolved in the Devonian period from sarcopterygian fish with lungs and bony-limbed fins, features that were helpful in adapting to dry land. They diversified and became dominant during the Carboniferous and Permian periods, but were later displaced by reptiles and other vertebrates. Over time, amphibians shrank in size and decreased in diversity, leaving only the modern subclass Lissamphibia.
+
+The three modern orders of amphibians are Anura (the frogs and toads), Urodela (the salamanders), and Apoda (the caecilians). The number of known amphibian species is approximately 8,000, of which nearly 90% are frogs. The smallest amphibian (and vertebrate) in the world is a frog from New Guinea (Paedophryne amauensis) with a length of just 7.7 mm (0.30 in). The largest living amphibian is the 1.8 m (5 ft 11 in) South China giant salamander (Andrias sligoi), but this is dwarfed by the extinct 9 m (30 ft) Prionosuchus from the middle Permian of Brazil. The study of amphibians is called batrachology, while the study of both reptiles and amphibians is called herpetology.
+
+The word "amphibian" is derived from the Ancient Greek term ἀμφίβιος (amphíbios), which means "both kinds of life", ἀμφί meaning "of both kinds" and βιος meaning "life". The term was initially used as a general adjective for animals that could live on land or in water, including seals and otters.[2] Traditionally, the class Amphibia includes all tetrapod vertebrates that are not amniotes. Amphibia in its widest sense (sensu lato) was divided into three subclasses, two of which are extinct:[3]
+
+The actual number of species in each group depends on the taxonomic classification followed. The two most common systems are the classification adopted by the website AmphibiaWeb, University of California, Berkeley and the classification by herpetologist Darrel Frost and the American Museum of Natural History, available as the online reference database "Amphibian Species of the World".[4] The numbers of species cited above follows Frost and the total number of known amphibian species as of March 31, 2019 is exactly 8,000,[5] of which nearly 90% are frogs.[6]
+
+With the phylogenetic classification, the taxon Labyrinthodontia has been discarded as it is a polyparaphyletic group without unique defining features apart from shared primitive characteristics. Classification varies according to the preferred phylogeny of the author and whether they use a stem-based or a node-based classification. Traditionally, amphibians as a class are defined as all tetrapods with a larval stage, while the group that includes the common ancestors of all living amphibians (frogs, salamanders and caecilians) and all their descendants is called Lissamphibia. The phylogeny of Paleozoic amphibians is uncertain, and Lissamphibia may possibly fall within extinct groups, like the Temnospondyli (traditionally placed in the subclass Labyrinthodontia) or the Lepospondyli, and in some analyses even in the amniotes. This means that advocates of phylogenetic nomenclature have removed a large number of basal Devonian and Carboniferous amphibian-type tetrapod groups that were formerly placed in Amphibia in Linnaean taxonomy, and included them elsewhere under cladistic taxonomy.[1] If the common ancestor of amphibians and amniotes is included in Amphibia, it becomes a paraphyletic group.[7]
+
+All modern amphibians are included in the subclass Lissamphibia, which is usually considered a clade, a group of species that have evolved from a common ancestor. The three modern orders are Anura (the frogs and toads), Caudata (or Urodela, the salamanders), and Gymnophiona (or Apoda, the caecilians).[8] It has been suggested that salamanders arose separately from a Temnospondyl-like ancestor, and even that caecilians are the sister group of the advanced reptiliomorph amphibians, and thus of amniotes.[9] Although the fossils of several older proto-frogs with primitive characteristics are known, the oldest "true frog" is Prosalirus bitis, from the Early Jurassic Kayenta Formation of Arizona. It is anatomically very similar to modern frogs.[10] The oldest known caecilian is another Early Jurassic species, Eocaecilia micropodia, also from Arizona.[11] The earliest salamander is Beiyanerpeton jianpingensis from the Late Jurassic of northeastern China.[12]
+
+Authorities disagree as to whether Salientia is a superorder that includes the order Anura, or whether Anura is a sub-order of the order Salientia. The Lissamphibia are traditionally divided into three orders, but an extinct salamander-like family, the Albanerpetontidae, is now considered part of Lissamphibia alongside the superorder Salientia. Furthermore, Salientia includes all three recent orders plus the Triassic proto-frog, Triadobatrachus.[13]
+
+The first major groups of amphibians developed in the Devonian period, around 370 million years ago, from lobe-finned fish which were similar to the modern coelacanth and lungfish.[14] These ancient lobe-finned fish had evolved multi-jointed leg-like fins with digits that enabled them to crawl along the sea bottom. Some fish had developed primitive lungs that help them breathe air when the stagnant pools of the Devonian swamps were low in oxygen. They could also use their strong fins to hoist themselves out of the water and onto dry land if circumstances so required. Eventually, their bony fins would evolve into limbs and they would become the ancestors to all tetrapods, including modern amphibians, reptiles, birds, and mammals. Despite being able to crawl on land, many of these prehistoric tetrapodomorph fish still spent most of their time in the water. They had started to develop lungs, but still breathed predominantly with gills.[15]
+
+Many examples of species showing transitional features have been discovered. Ichthyostega was one of the first primitive amphibians, with nostrils and more efficient lungs. It had four sturdy limbs, a neck, a tail with fins and a skull very similar to that of the lobe-finned fish, Eusthenopteron.[14] Amphibians evolved adaptations that allowed them to stay out of the water for longer periods. Their lungs improved and their skeletons became heavier and stronger, better able to support the weight of their bodies on land. They developed "hands" and "feet" with five or more digits;[16] the skin became more capable of retaining body fluids and resisting desiccation.[15] The fish's hyomandibula bone in the hyoid region behind the gills diminished in size and became the stapes of the amphibian ear, an adaptation necessary for hearing on dry land.[17] An affinity between the amphibians and the teleost fish is the multi-folded structure of the teeth and the paired supra-occipital bones at the back of the head, neither of these features being found elsewhere in the animal kingdom.[18]
+
+At the end of the Devonian period (360 million years ago), the seas, rivers and lakes were teeming with life while the land was the realm of early plants and devoid of vertebrates,[18] though some, such as Ichthyostega, may have sometimes hauled themselves out of the water. It is thought they may have propelled themselves with their forelimbs, dragging their hindquarters in a similar manner to that used by the elephant seal.[16] In the early Carboniferous (360 to 345 million years ago), the climate became wet and warm. Extensive swamps developed with mosses, ferns, horsetails and calamites. Air-breathing arthropods evolved and invaded the land where they provided food for the carnivorous amphibians that began to adapt to the terrestrial environment. There were no other tetrapods on the land and the amphibians were at the top of the food chain, occupying the ecological position currently held by the crocodile. Though equipped with limbs and the ability to breathe air, most still had a long tapering body and strong tail.[18] They were the top land predators, sometimes reaching several metres in length, preying on the large insects of the period and the many types of fish in the water. They still needed to return to water to lay their shell-less eggs, and even most modern amphibians have a fully aquatic larval stage with gills like their fish ancestors. It was the development of the amniotic egg, which prevents the developing embryo from drying out, that enabled the reptiles to reproduce on land and which led to their dominance in the period that followed.[14]
+
+After the Carboniferous rainforest collapse amphibian dominance gave way to reptiles,[19] and amphibians were further devastated by the Permian–Triassic extinction event.[20] During the Triassic Period (250 to 200 million years ago), the reptiles continued to out-compete the amphibians, leading to a reduction in both the amphibians' size and their importance in the biosphere. According to the fossil record, Lissamphibia, which includes all modern amphibians and is the only surviving lineage, may have branched off from the extinct groups Temnospondyli and Lepospondyli at some period between the Late Carboniferous and the Early Triassic. The relative scarcity of fossil evidence precludes precise dating,[15] but the most recent molecular study, based on multilocus sequence typing, suggests a Late Carboniferous/Early Permian origin for extant amphibians.[21]
+
+The origins and evolutionary relationships between the three main groups of amphibians is a matter of debate. A 2005 molecular phylogeny, based on rDNA analysis, suggests that salamanders and caecilians are more closely related to each other than they are to frogs. It also appears that the divergence of the three groups took place in the Paleozoic or early Mesozoic (around 250 million years ago), before the breakup of the supercontinent Pangaea and soon after their divergence from the lobe-finned fish. The briefness of this period, and the swiftness with which radiation took place, would help account for the relative scarcity of primitive amphibian fossils.[22] There are large gaps in the fossil record, but the discovery of a Gerobatrachus hottoni from the Early Permian in Texas in 2008 provided a missing link with many of the characteristics of modern frogs.[9] Molecular analysis suggests that the frog–salamander divergence took place considerably earlier than the palaeontological evidence indicates.[9] Newer research indicates that the common ancestor of all Lissamphibians lived about 315 million years ago, and that stereospondyls are the closest relatives to the caecilians.[23]
+
+As they evolved from lunged fish, amphibians had to make certain adaptations for living on land, including the need to develop new means of locomotion. In the water, the sideways thrusts of their tails had propelled them forward, but on land, quite different mechanisms were required. Their vertebral columns, limbs, limb girdles and musculature needed to be strong enough to raise them off the ground for locomotion and feeding. Terrestrial adults discarded their lateral line systems and adapted their sensory systems to receive stimuli via the medium of the air. They needed to develop new methods to regulate their body heat to cope with fluctuations in ambient temperature. They developed behaviours suitable for reproduction in a terrestrial environment. Their skins were exposed to harmful ultraviolet rays that had previously been absorbed by the water. The skin changed to become more protective and prevent excessive water loss.[24]
+
+The superclass Tetrapoda is divided into four classes of vertebrate animals with four limbs.[25] Reptiles, birds and mammals are amniotes, the eggs of which are either laid or carried by the female and are surrounded by several membranes, some of which are impervious.[26] Lacking these membranes, amphibians require water bodies for reproduction, although some species have developed various strategies for protecting or bypassing the vulnerable aquatic larval stage.[24] They are not found in the sea with the exception of one or two frogs that live in brackish water in mangrove swamps;[27] the Anderson's salamander meanwhile occurs in brackish or salt water lakes.[28] On land, amphibians are restricted to moist habitats because of the need to keep their skin damp.[24]
+
+Modern amphibians have a simplified anatomy compared to their ancestors due to paedomorphosis, caused by two evolutionary trends: miniaturization and an unusually large genome, which result in a slower growth and development rate compared to other vertebrates.[29][30] Another reason for their size is associated with their rapid metamorphosis, which seems to have evolved only in the ancestors of lissamphibia; in all other known lines the development was much more gradual. Because a remodeling of the feeding apparatus means they don't eat during the metamorphosis, the metamorphosis has to go faster the smaller the individual is, so it happens at an early stage when the larvae are still small. (The largest species of salamanders don't go through a metamorphosis.)[31] Amphibians that lay eggs on land often go through the whole metamorphosis inside the egg. An anamniotic terrestrial egg is less than 1 cm in diameter due to diffusion problems, a size which puts a limit on the amount of posthatching growth.[32]
+
+The smallest amphibian (and vertebrate) in the world is a microhylid frog from New Guinea (Paedophryne amauensis) first discovered in 2012. It has an average length of 7.7 mm (0.30 in) and is part of a genus that contains four of the world's ten smallest frog species.[33] The largest living amphibian is the 1.8 m (5 ft 11 in) Chinese giant salamander (Andrias davidianus)[34] but this is a great deal smaller than the largest amphibian that ever existed—the extinct 9 m (30 ft) Prionosuchus, a crocodile-like temnospondyl dating to 270 million years ago from the middle Permian of Brazil.[35] The largest frog is the African Goliath frog (Conraua goliath), which can reach 32 cm (13 in) and weigh 3 kg (6.6 lb).[34]
+
+Amphibians are ectothermic (cold-blooded) vertebrates that do not maintain their body temperature through internal physiological processes. Their metabolic rate is low and as a result, their food and energy requirements are limited. In the adult state, they have tear ducts and movable eyelids, and most species have ears that can detect airborne or ground vibrations. They have muscular tongues, which in many species can be protruded. Modern amphibians have fully ossified vertebrae with articular processes. Their ribs are usually short and may be fused to the vertebrae. Their skulls are mostly broad and short, and are often incompletely ossified. Their skin contains little keratin and lacks scales, apart from a few fish-like scales in certain caecilians. The skin contains many mucous glands and in some species, poison glands (a type of granular gland). The hearts of amphibians have three chambers, two atria and one ventricle. They have a urinary bladder and nitrogenous waste products are excreted primarily as urea. Most amphibians lay their eggs in water and have aquatic larvae that undergo metamorphosis to become terrestrial adults. Amphibians breathe by means of a pump action in which air is first drawn into the buccopharyngeal region through the nostrils. These are then closed and the air is forced into the lungs by contraction of the throat.[36] They supplement this with gas exchange through the skin.[24]
+
+The order Anura (from the Ancient Greek a(n)- meaning "without" and oura meaning "tail") comprises the frogs and toads. They usually have long hind limbs that fold underneath them, shorter forelimbs, webbed toes with no claws, no tails, large eyes and glandular moist skin.[8] Members of this order with smooth skins are commonly referred to as frogs, while those with warty skins are known as toads. The difference is not a formal one taxonomically and there are numerous exceptions to this rule. Members of the family Bufonidae are known as the "true toads".[37] Frogs range in size from the 30-centimetre (12 in) Goliath frog (Conraua goliath) of West Africa[38] to the 7.7-millimetre (0.30 in) Paedophryne amauensis, first described in Papua New Guinea in 2012, which is also the smallest known vertebrate.[39] Although most species are associated with water and damp habitats, some are specialised to live in trees or in deserts. They are found worldwide except for polar areas.[40]
+
+Anura is divided into three suborders that are broadly accepted by the scientific community, but the relationships between some families remain unclear. Future molecular studies should provide further insights into their evolutionary relationships.[41] The suborder Archaeobatrachia contains four families of primitive frogs. These are Ascaphidae, Bombinatoridae, Discoglossidae and Leiopelmatidae which have few derived features and are probably paraphyletic with regard to other frog lineages.[42] The six families in the more evolutionarily advanced suborder Mesobatrachia are the fossorial Megophryidae, Pelobatidae, Pelodytidae, Scaphiopodidae and Rhinophrynidae and the obligatorily aquatic Pipidae. These have certain characteristics that are intermediate between the two other suborders.[42] Neobatrachia is by far the largest suborder and includes the remaining families of modern frogs, including most common species. Ninety-six percent of the over 5,000 extant species of frog are neobatrachians.[43]
+
+The order Caudata (from the Latin cauda meaning "tail") consists of the salamanders—elongated, low-slung animals that mostly resemble lizards in form. This is a symplesiomorphic trait and they are no more closely related to lizards than they are to mammals.[44] Salamanders lack claws, have scale-free skins, either smooth or covered with tubercles, and tails that are usually flattened from side to side and often finned. They range in size from the Chinese giant salamander (Andrias davidianus), which has been reported to grow to a length of 1.8 metres (5 ft 11 in),[45] to the diminutive Thorius pennatulus from Mexico which seldom exceeds 20 mm (0.8 in) in length.[46] Salamanders have a mostly Laurasian distribution, being present in much of the Holarctic region of the northern hemisphere. The family Plethodontidae is also found in Central America and South America north of the Amazon basin;[40] South America was apparently invaded from Central America by about the start of the Miocene, 23 million years ago.[47] Urodela is a name sometimes used for all the extant species of salamanders.[48] Members of several salamander families have become paedomorphic and either fail to complete their metamorphosis or retain some larval characteristics as adults.[49] Most salamanders are under 15 cm (6 in) long. They may be terrestrial or aquatic and many spend part of the year in each habitat. When on land, they mostly spend the day hidden under stones or logs or in dense vegetation, emerging in the evening and night to forage for worms, insects and other invertebrates.[40]
+
+The suborder Cryptobranchoidea contains the primitive salamanders. A number of fossil cryptobranchids have been found, but there are only three living species, the Chinese giant salamander (Andrias davidianus), the Japanese giant salamander (Andrias japonicus) and the hellbender (Cryptobranchus alleganiensis) from North America. These large amphibians retain several larval characteristics in their adult state; gills slits are present and the eyes are unlidded. A unique feature is their ability to feed by suction, depressing either the left side of their lower jaw or the right.[50] The males excavate nests, persuade females to lay their egg strings inside them, and guard them. As well as breathing with lungs, they respire through the many folds in their thin skin, which has capillaries close to the surface.[51]
+
+The suborder Salamandroidea contains the advanced salamanders. They differ from the cryptobranchids by having fused prearticular bones in the lower jaw, and by using internal fertilisation. In salamandrids, the male deposits a bundle of sperm, the spermatophore, and the female picks it up and inserts it into her cloaca where the sperm is stored until the eggs are laid.[52] The largest family in this group is Plethodontidae, the lungless salamanders, which includes 60% of all salamander species. The family Salamandridae includes the true salamanders and the name "newt" is given to members of its subfamily Pleurodelinae.[8]
+
+The third suborder, Sirenoidea, contains the four species of sirens, which are in a single family, Sirenidae. Members of this order are eel-like aquatic salamanders with much reduced forelimbs and no hind limbs. Some of their features are primitive while others are derived.[53] Fertilisation is likely to be external as sirenids lack the cloacal glands used by male salamandrids to produce spermatophores and the females lack spermathecae for sperm storage. Despite this, the eggs are laid singly, a behaviour not conducive for external fertilisation.[52]
+
+The order Gymnophiona (from the Greek gymnos meaning "naked" and ophis meaning "serpent") or Apoda comprises the caecilians. These are long, cylindrical, limbless animals with a snake- or worm-like form. The adults vary in length from 8 to 75 centimetres (3 to 30 inches) with the exception of Thomson's caecilian (Caecilia thompsoni), which can reach 150 centimetres (4.9 feet). A caecilian's skin has a large number of transverse folds and in some species contains tiny embedded dermal scales. It has rudimentary eyes covered in skin, which are probably limited to discerning differences in light intensity. It also has a pair of short tentacles near the eye that can be extended and which have tactile and olfactory functions. Most caecilians live underground in burrows in damp soil, in rotten wood and under plant debris, but some are aquatic.[54] Most species lay their eggs underground and when the larvae hatch, they make their way to adjacent bodies of water. Others brood their eggs and the larvae undergo metamorphosis before the eggs hatch. A few species give birth to live young, nourishing them with glandular secretions while they are in the oviduct.[55] Caecilians have a mostly Gondwanan distribution, being found in tropical regions of Africa, Asia and Central and South America.[56]
+
+The integumentary structure contains some typical characteristics common to terrestrial vertebrates, such as the presence of highly cornified outer layers, renewed periodically through a moulting process controlled by the pituitary and thyroid glands. Local thickenings (often called warts) are common, such as those found on toads. The outside of the skin is shed periodically mostly in one piece, in contrast to mammals and birds where it is shed in flakes. Amphibians often eat the sloughed skin.[40] Caecilians are unique among amphibians in having mineralized dermal scales embedded in the dermis between the furrows in the skin. The similarity of these to the scales of bony fish is largely superficial. Lizards and some frogs have somewhat similar osteoderms forming bony deposits in the dermis, but this is an example of convergent evolution with similar structures having arisen independently in diverse vertebrate lineages.[57]
+
+Amphibian skin is permeable to water. Gas exchange can take place through the skin (cutaneous respiration) and this allows adult amphibians to respire without rising to the surface of water and to hibernate at the bottom of ponds.[40] To compensate for their thin and delicate skin, amphibians have evolved mucous glands, principally on their heads, backs and tails. The secretions produced by these help keep the skin moist. In addition, most species of amphibian have granular glands that secrete distasteful or poisonous substances. Some amphibian toxins can be lethal to humans while others have little effect.[58] The main poison-producing glands, the parotoids, produce the neurotoxin bufotoxin and are located behind the ears of toads, along the backs of frogs, behind the eyes of salamanders and on the upper surface of caecilians.[59]
+
+The skin colour of amphibians is produced by three layers of pigment cells called chromatophores. These three cell layers consist of the melanophores (occupying the deepest layer), the guanophores (forming an intermediate layer and containing many granules, producing a blue-green colour) and the lipophores (yellow, the most superficial layer). The colour change displayed by many species is initiated by hormones secreted by the pituitary gland. Unlike bony fish, there is no direct control of the pigment cells by the nervous system, and this results in the colour change taking place more slowly than happens in fish. A vividly coloured skin usually indicates that the species is toxic and is a warning sign to predators.[60]
+
+Amphibians have a skeletal system that is structurally homologous to other tetrapods, though with a number of variations. They all have four limbs except for the legless caecilians and a few species of salamander with reduced or no limbs. The bones are hollow and lightweight. The musculoskeletal system is strong to enable it to support the head and body. The bones are fully ossified and the vertebrae interlock with each other by means of overlapping processes. The pectoral girdle is supported by muscle, and the well-developed pelvic girdle is attached to the backbone by a pair of sacral ribs. The ilium slopes forward and the body is held closer to the ground than is the case in mammals.[61]
+
+In most amphibians, there are four digits on the fore foot and five on the hind foot, but no claws on either. Some salamanders have fewer digits and the amphiumas are eel-like in appearance with tiny, stubby legs. The sirens are aquatic salamanders with stumpy forelimbs and no hind limbs. The caecilians are limbless. They burrow in the manner of earthworms with zones of muscle contractions moving along the body. On the surface of the ground or in water they move by undulating their body from side to side.[62]
+
+In frogs, the hind legs are larger than the fore legs, especially so in those species that principally move by jumping or swimming. In the walkers and runners the hind limbs are not so large, and the burrowers mostly have short limbs and broad bodies. The feet have adaptations for the way of life, with webbing between the toes for swimming, broad adhesive toe pads for climbing, and keratinised tubercles on the hind feet for digging (frogs usually dig backwards into the soil). In most salamanders, the limbs are short and more or less the same length and project at right angles from the body. Locomotion on land is by walking and the tail often swings from side to side or is used as a prop, particularly when climbing. In their normal gait, only one leg is advanced at a time in the manner adopted by their ancestors, the lobe-finned fish.[61] Some salamanders in the genus Aneides and certain plethodontids climb trees and have long limbs, large toepads and prehensile tails.[52] In aquatic salamanders and in frog tadpoles, the tail has dorsal and ventral fins and is moved from side to side as a means of propulsion. Adult frogs do not have tails and caecilians have only very short ones.[62]
+
+Salamanders use their tails in defence and some are prepared to jettison them to save their lives in a process known as autotomy. Certain species in the Plethodontidae have a weak zone at the base of the tail and use this strategy readily. The tail often continues to twitch after separation which may distract the attacker and allow the salamander to escape. Both tails and limbs can be regenerated.[63] Adult frogs are unable to regrow limbs but tadpoles can do so.[62]
+
+Amphibians have a juvenile stage and an adult stage, and the circulatory systems of the two are distinct. In the juvenile (or tadpole) stage, the circulation is similar to that of a fish; the two-chambered heart pumps the blood through the gills where it is oxygenated, and is spread around the body and back to the heart in a single loop. In the adult stage, amphibians (especially frogs) lose their gills and develop lungs. They have a heart that consists of a single ventricle and two atria. When the ventricle starts contracting, deoxygenated blood is pumped through the pulmonary artery to the lungs. Continued contraction then pumps oxygenated blood around the rest of the body. Mixing of the two bloodstreams is minimized by the anatomy of the chambers.[64]
+
+The nervous system is basically the same as in other vertebrates, with a central brain, a spinal cord, and nerves throughout the body. The amphibian brain is less well developed than that of reptiles, birds and mammals but is similar in morphology and function to that of a fish. It is believed amphibians are capable of perceiving pain.  The brain consists of equal parts, cerebrum, midbrain and cerebellum. Various parts of the cerebrum process sensory input, such as smell in the olfactory lobe and sight in the optic lobe, and it is additionally the centre of behaviour and learning. The cerebellum is the center of muscular coordination and the medulla oblongata controls some organ functions including heartbeat and respiration. The brain sends signals through the spinal cord and nerves to regulate activity in the rest of the body. The pineal body, known to regulate sleep patterns in humans, is thought to produce the hormones involved in hibernation and aestivation in amphibians.[65]
+
+Tadpoles retain the lateral line system of their ancestral fishes, but this is lost in terrestrial adult amphibians. Some caecilians possess electroreceptors that allow them to locate objects around them when submerged in water. The ears are well developed in frogs. There is no external ear, but the large circular eardrum lies on the surface of the head just behind the eye. This vibrates and sound is transmitted through a single bone, the stapes, to the inner ear. Only high-frequency sounds like mating calls are heard in this way, but low-frequency noises can be detected through another mechanism.[61] There is a patch of specialized haircells, called papilla amphibiorum, in the inner ear capable of detecting deeper sounds. Another feature, unique to frogs and salamanders, is the columella-operculum complex adjoining the auditory capsule which is involved in the transmission of both airborne and seismic signals.[66] The ears of salamanders and caecilians are less highly developed than those of frogs as they do not normally communicate with each other through the medium of sound.[67]
+
+The eyes of tadpoles lack lids, but at metamorphosis, the cornea becomes more dome-shaped, the lens becomes flatter, and eyelids and associated glands and ducts develop.[61] The adult eyes are an improvement on invertebrate eyes and were a first step in the development of more advanced vertebrate eyes. They allow colour vision and depth of focus. In the retinas are green rods, which are receptive to a wide range of wavelengths.[67]
+
+Many amphibians catch their prey by flicking out an elongated tongue with a sticky tip and drawing it back into the mouth before seizing the item with their jaws. Some use inertial feeding to help them swallow the prey, repeatedly thrusting their head forward sharply causing the food to move backwards in their mouth by inertia. Most amphibians swallow their prey whole without much chewing so they possess voluminous stomachs. The short oesophagus is lined with cilia that help to move the food to the stomach and mucus produced by glands in the mouth and pharynx eases its passage. The enzyme chitinase produced in the stomach helps digest the chitinous cuticle of arthropod prey.[68]
+
+Amphibians possess a pancreas, liver and gall bladder. The liver is usually large with two lobes. Its size is determined by its function as a glycogen and fat storage unit, and may change with the seasons as these reserves are built or used up. Adipose tissue is another important means of storing energy and this occurs in the abdomen (in internal structures called fat bodies), under the skin and, in some salamanders, in the tail.[69]
+
+There are two kidneys located dorsally, near the roof of the body cavity. Their job is to filter the blood of metabolic waste and transport the urine via ureters to the urinary bladder where it is stored before being passed out periodically through the cloacal vent. Larvae and most aquatic adult amphibians excrete the nitrogen as ammonia in large quantities of dilute urine, while terrestrial species, with a greater need to conserve water, excrete the less toxic product urea. Some tree frogs with limited access to water excrete most of their metabolic waste as uric acid.[70]
+
+The lungs in amphibians are primitive compared to those of amniotes, possessing few internal septa and large alveoli, and consequently having a comparatively slow diffusion rate for oxygen entering the blood. Ventilation is accomplished by buccal pumping.[71] Most amphibians, however, are able to exchange gases with the water or air via their skin. To enable sufficient cutaneous respiration, the surface of their highly vascularised skin must remain moist to allow the oxygen to diffuse at a sufficiently high rate.[68] Because oxygen concentration in the water increases at both low temperatures and high flow rates, aquatic amphibians in these situations can rely primarily on cutaneous respiration, as in the Titicaca water frog and the hellbender salamander. In air, where oxygen is more concentrated, some small species can rely solely on cutaneous gas exchange, most famously the plethodontid salamanders, which have neither lungs nor gills. Many aquatic salamanders and all tadpoles have gills in their larval stage, with some (such as the axolotl) retaining gills as aquatic adults.[68]
+
+For the purpose of reproduction most amphibians require fresh water although some lay their eggs on land and have developed various means of keeping them moist. A few (e.g. Fejervarya raja) can inhabit brackish water, but there are no true marine amphibians.[72] There are reports, however, of particular amphibian populations unexpectedly invading marine waters. Such was the case with the Black Sea invasion of the natural hybrid Pelophylax esculentus reported in 2010.[73]
+
+Several hundred frog species in adaptive radiations (e.g., Eleutherodactylus, the Pacific Platymantis, the Australo-Papuan microhylids, and many other tropical frogs), however, do not need any water for breeding in the wild. They reproduce via direct development, an ecological and evolutionary adaptation that has allowed them to be completely independent from free-standing water. Almost all of these frogs live in wet tropical rainforests and their eggs hatch directly into miniature versions of the adult, passing through the tadpole stage within the egg. Reproductive success of many amphibians is dependent not only on the quantity of rainfall, but the seasonal timing.[74]
+
+In the tropics, many amphibians breed continuously or at any time of year. In temperate regions, breeding is mostly seasonal, usually in the spring, and is triggered by increasing day length, rising temperatures or rainfall. Experiments have shown the importance of temperature, but the trigger event, especially in arid regions, is often a storm. In anurans, males usually arrive at the breeding sites before females and the vocal chorus they produce may stimulate ovulation in females and the endocrine activity of males that are not yet reproductively active.[75]
+
+In caecilians, fertilisation is internal, the male extruding an intromittent organ, the phallodeum, and inserting it into the female cloaca. The paired Müllerian glands inside the male cloaca secrete a fluid which resembles that produced by mammalian prostate glands and which may transport and nourish the sperm. Fertilisation probably takes place in the oviduct.[76]
+
+The majority of salamanders also engage in internal fertilisation. In most of these, the male deposits a spermatophore, a small packet of sperm on top of a gelatinous cone, on the substrate either on land or in the water. The female takes up the sperm packet by grasping it with the lips of the cloaca and pushing it into the vent. The spermatozoa move to the spermatheca in the roof of the cloaca where they remain until ovulation which may be many months later. Courtship rituals and methods of transfer of the spermatophore vary between species. In some, the spermatophore may be placed directly into the female cloaca while in others, the female may be guided to the spermatophore or restrained with an embrace called amplexus. Certain primitive salamanders in the families Sirenidae, Hynobiidae and Cryptobranchidae practice external fertilisation in a similar manner to frogs, with the female laying the eggs in water and the male releasing sperm onto the egg mass.[76]
+
+With a few exceptions, frogs use external fertilisation. The male grasps the female tightly with his forelimbs either behind the arms or in front of the back legs, or in the case of Epipedobates tricolor, around the neck. They remain in amplexus with their cloacae positioned close together while the female lays the eggs and the male covers them with sperm. Roughened nuptial pads on the male's hands aid in retaining grip. Often the male collects and retains the egg mass, forming a sort of basket with the hind feet. An exception is the granular poison frog (Oophaga granulifera) where the male and female place their cloacae in close proximity while facing in opposite directions and then release eggs and sperm simultaneously. The tailed frog (Ascaphus truei) exhibits internal fertilisation. The "tail" is only possessed by the male and is an extension of the cloaca and used to inseminate the female. This frog lives in fast-flowing streams and internal fertilisation prevents the sperm from being washed away before fertilisation occurs.[77] The sperm may be retained in storage tubes attached to the oviduct until the following spring.[78]
+
+Most frogs can be classified as either prolonged or explosive breeders. Typically, prolonged breeders congregate at a breeding site, the males usually arriving first, calling and setting up territories. Other satellite males remain quietly nearby, waiting for their opportunity to take over a territory. The females arrive sporadically, mate selection takes place and eggs are laid. The females depart and territories may change hands. More females appear and in due course, the breeding season comes to an end. Explosive breeders on the other hand are found where temporary pools appear in dry regions after rainfall. These frogs are typically fossorial species that emerge after heavy rains and congregate at a breeding site. They are attracted there by the calling of the first male to find a suitable place, perhaps a pool that forms in the same place each rainy season. The assembled frogs may call in unison and frenzied activity ensues, the males scrambling to mate with the usually smaller number of females.[77]
+
+There is a direct competition between males to win the attention of the females in salamanders and newts, with elaborate courtship displays to keep the female's attention long enough to get her interested in choosing him to mate with.[79] Some species store sperm through long breeding seasons, as the extra time may allow for interactions with rival sperm.[80]
+
+Most amphibians go through metamorphosis, a process of significant morphological change after birth. In typical amphibian development, eggs are laid in water and larvae are adapted to an aquatic lifestyle. Frogs, toads and salamanders all hatch from the egg as larvae with external gills. Metamorphosis in amphibians is regulated by thyroxine concentration in the blood, which stimulates metamorphosis, and prolactin, which counteracts thyroxine's effect. Specific events are dependent on threshold values for different tissues.[81] Because most embryonic development is outside the parental body, it is subject to many adaptations due to specific environmental circumstances. For this reason tadpoles can have horny ridges instead of teeth, whisker-like skin extensions or fins. They also make use of a sensory lateral line organ similar to that of fish. After metamorphosis, these organs become redundant and will be reabsorbed by controlled cell death, called apoptosis. The variety of adaptations to specific environmental circumstances among amphibians is wide, with many discoveries still being made.[82]
+
+The egg of an amphibian is typically surrounded by a transparent gelatinous covering secreted by the oviducts and containing mucoproteins and mucopolysaccharides. This capsule is permeable to water and gases, and swells considerably as it absorbs water. The ovum is at first rigidly held, but in fertilised eggs the innermost layer liquefies and allows the embryo to move freely. This also happens in salamander eggs, even when they are unfertilised. Eggs of some salamanders and frogs contain unicellular green algae. These penetrate the jelly envelope after the eggs are laid and may increase the supply of oxygen to the embryo through photosynthesis. They seem to both speed up the development of the larvae and reduce mortality.[83] Most eggs contain the pigment melanin which raises their temperature through the absorption of light and also protects them against ultraviolet radiation. Caecilians, some plethodontid salamanders and certain frogs lay eggs underground that are unpigmented. In the wood frog (Rana sylvatica), the interior of the globular egg cluster has been found to be up to 6 °C (11 °F) warmer than its surroundings, which is an advantage in its cool northern habitat.[84]
+
+The eggs may be deposited singly or in small groups, or may take the form of spherical egg masses, rafts or long strings. In terrestrial caecilians, the eggs are laid in grape-like clusters in burrows near streams. The amphibious salamander Ensatina attaches its similar clusters by stalks to underwater stems and roots. The greenhouse frog (Eleutherodactylus planirostris) lays eggs in small groups in the soil where they develop in about two weeks directly into juvenile frogs without an intervening larval stage.[85] The tungara frog (Physalaemus pustulosus) builds a floating nest from foam to protect its eggs. First a raft is built, then eggs are laid in the centre, and finally a foam cap is overlaid. The foam has anti-microbial properties. It contains no detergents but is created by whipping up proteins and lectins secreted by the female.[86][87]
+
+The eggs of amphibians are typically laid in water and hatch into free-living larvae that complete their development in water and later transform into either aquatic or terrestrial adults. In many species of frog and in most lungless salamanders (Plethodontidae), direct development takes place, the larvae growing within the eggs and emerging as miniature adults. Many caecilians and some other amphibians lay their eggs on land, and the newly hatched larvae wriggle or are transported to water bodies. Some caecilians, the alpine salamander (Salamandra atra) and some of the African live-bearing toads (Nectophrynoides spp.) are viviparous. Their larvae feed on glandular secretions and develop within the female's oviduct, often for long periods. Other amphibians, but not caecilians, are ovoviviparous. The eggs are retained in or on the parent's body, but the larvae subsist on the yolks of their eggs and receive no nourishment from the adult. The larvae emerge at varying stages of their growth, either before or after metamorphosis, according to their species.[88] The toad genus Nectophrynoides exhibits all of these developmental patterns among its dozen or so members.[6]
+
+Frog larvae are known as tadpoles and typically have oval bodies and long, vertically flattened tails with fins. The free-living larvae are normally fully aquatic, but the tadpoles of some species (such as Nannophrys ceylonensis) are semi-terrestrial and live among wet rocks.[89] Tadpoles have cartilaginous skeletons, gills for respiration (external gills at first, internal gills later), lateral line systems and large tails that they use for swimming.[90] Newly hatched tadpoles soon develop gill pouches that cover the gills. The lungs develop early and are used as accessory breathing organs, the tadpoles rising to the water surface to gulp air. Some species complete their development inside the egg and hatch directly into small frogs. These larvae do not have gills but instead have specialised areas of skin through which respiration takes place. While tadpoles do not have true teeth, in most species, the jaws have long, parallel rows of small keratinized structures called keradonts surrounded by a horny beak.[91] Front legs are formed under the gill sac and hind legs become visible a few days later.
+
+Iodine and T4 (over stimulate the spectacular apoptosis [programmed cell death] of the cells of the larval gills, tail and fins) also stimulate the evolution of nervous systems transforming the aquatic, vegetarian tadpole into the terrestrial, carnivorous frog with better neurological, visuospatial, olfactory and cognitive abilities for hunting.[92][93]
+
+In fact, tadpoles developing in ponds and streams are typically herbivorous. Pond tadpoles tend to have deep bodies, large caudal fins and small mouths; they swim in the quiet waters feeding on growing or loose fragments of vegetation. Stream dwellers mostly have larger mouths, shallow bodies and caudal fins; they attach themselves to plants and stones and feed on the surface films of algae and bacteria.[94] They also feed on diatoms, filtered from the water through the gills, and stir up the sediment at bottom of the pond, ingesting edible fragments. They have a relatively long, spiral-shaped gut to enable them to digest this diet.[94] Some species are carnivorous at the tadpole stage, eating insects, smaller tadpoles and fish. Young of the Cuban tree frog (Osteopilus septentrionalis) can occasionally be cannibalistic, the younger tadpoles attacking a larger, more developed tadpole when it is undergoing metamorphosis.[95]
+
+At metamorphosis, rapid changes in the body take place as the lifestyle of the frog changes completely. The spiral‐shaped mouth with horny tooth ridges is reabsorbed together with the spiral gut. The animal develops a large jaw, and its gills disappear along with its gill sac. Eyes and legs grow quickly, and a tongue is formed. There are associated changes in the neural networks such as development of stereoscopic vision and loss of the lateral line system. All this can happen in about a day. A few days later, the tail is reabsorbed, due to the higher thyroxine concentration required for this to take place.[94]
+
+At hatching, a typical salamander larva has eyes without lids, teeth in both upper and lower jaws, three pairs of feathery external gills, a somewhat laterally flattened body and a long tail with dorsal and ventral fins. The forelimbs may be partially developed and the hind limbs are rudimentary in pond-living species but may be rather more developed in species that reproduce in moving water. Pond-type larvae often have a pair of balancers, rod-like structures on either side of the head that may prevent the gills from becoming clogged up with sediment. Some members of the genera Ambystoma and Dicamptodon have larvae that never fully develop into the adult form, but this varies with species and with populations. The northwestern salamander (Ambystoma gracile) is one of these and, depending on environmental factors, either remains permanently in the larval state, a condition known as neoteny, or transforms into an adult.[96] Both of these are able to breed.[97] Neoteny occurs when the animal's growth rate is very low and is usually linked to adverse conditions such as low water temperatures that may change the response of the tissues to the hormone thyroxine.[98] Other factors that may inhibit metamorphosis include lack of food, lack of trace elements and competition from conspecifics. The tiger salamander (Ambystoma tigrinum) also sometimes behaves in this way and may grow particularly large in the process. The adult tiger salamander is terrestrial, but the larva is aquatic and able to breed while still in the larval state. When conditions are particularly inhospitable on land, larval breeding may allow continuation of a population that would otherwise die out. There are fifteen species of obligate neotenic salamanders, including species of Necturus, Proteus and Amphiuma, and many examples of facultative ones that adopt this strategy under appropriate environmental circumstances.[99]
+
+Lungless salamanders in the family Plethodontidae are terrestrial and lay a small number of unpigmented eggs in a cluster among damp leaf litter. Each egg has a large yolk sac and the larva feeds on this while it develops inside the egg, emerging fully formed as a juvenile salamander. The female salamander often broods the eggs. In the genus Ensatinas, the female has been observed to coil around them and press her throat area against them, effectively massaging them with a mucous secretion.[100]
+
+In newts and salamanders, metamorphosis is less dramatic than in frogs. This is because the larvae are already carnivorous and continue to feed as predators when they are adults so few changes are needed to their digestive systems. Their lungs are functional early, but the larvae do not make as much use of them as do tadpoles. Their gills are never covered by gill sacs and are reabsorbed just before the animals leave the water. Other changes include the reduction in size or loss of tail fins, the closure of gill slits, thickening of the skin, the development of eyelids, and certain changes in dentition and tongue structure. Salamanders are at their most vulnerable at metamorphosis as swimming speeds are reduced and transforming tails are encumbrances on land.[101] Adult salamanders often have an aquatic phase in spring and summer, and a land phase in winter. For adaptation to a water phase, prolactin is the required hormone, and for adaptation to the land phase, thyroxine. External gills do not return in subsequent aquatic phases because these are completely absorbed upon leaving the water for the first time.[102]
+
+Most terrestrial caecilians that lay eggs do so in burrows or moist places on land near bodies of water. The development of the young of Ichthyophis glutinosus, a species from Sri Lanka, has been much studied. The eel-like larvae hatch out of the eggs and make their way to water. They have three pairs of external red feathery gills, a blunt head with two rudimentary eyes, a lateral line system and a short tail with fins. They swim by undulating their body from side to side. They are mostly active at night, soon lose their gills and make sorties onto land. Metamorphosis is gradual. By the age of about ten months they have developed a pointed head with sensory tentacles near the mouth and lost their eyes, lateral line systems and tails. The skin thickens, embedded scales develop and the body divides into segments. By this time, the caecilian has constructed a burrow and is living on land.[103]
+
+In the majority of species of caecilians, the young are produced by viviparity. Typhlonectes compressicauda, a species from South America, is typical of these. Up to nine larvae can develop in the oviduct at any one time. They are elongated and have paired sac-like gills, small eyes and specialised scraping teeth. At first, they feed on the yolks of the eggs, but as this source of nourishment declines they begin to rasp at the ciliated epithelial cells that line the oviduct. This stimulates the secretion of fluids rich in lipids and mucoproteins on which they feed along with scrapings from the oviduct wall. They may increase their length sixfold and be two-fifths as long as their mother before being born. By this time they have undergone metamorphosis, lost their eyes and gills, developed a thicker skin and mouth tentacles, and reabsorbed their teeth. A permanent set of teeth grow through soon after birth.[104][105]
+
+The ringed caecilian (Siphonops annulatus) has developed a unique adaptation for the purposes of reproduction. The progeny feed on a skin layer that is specially developed by the adult in a phenomenon known as maternal dermatophagy. The brood feed as a batch for about seven minutes at intervals of approximately three days which gives the skin an opportunity to regenerate. Meanwhile, they have been observed to ingest fluid exuded from the maternal cloaca.[106]
+
+The care of offspring among amphibians has been little studied but, in general, the larger the number of eggs in a batch, the less likely it is that any degree of parental care takes place. Nevertheless, it is estimated that in up to 20% of amphibian species, one or both adults play some role in the care of the young.[107] Those species that breed in smaller water bodies or other specialised habitats tend to have complex patterns of behaviour in the care of their young.[108]
+
+Many woodland salamanders lay clutches of eggs under dead logs or stones on land. The black mountain salamander (Desmognathus welteri) does this, the mother brooding the eggs and guarding them from predation as the embryos feed on the yolks of their eggs. When fully developed, they break their way out of the egg capsules and disperse as juvenile salamanders.[109] The male hellbender, a primitive salamander, excavates an underwater nest and encourages females to lay there. The male then guards the site for the two or three months before the eggs hatch, using body undulations to fan the eggs and increase their supply of oxygen.[51]
+
+The male Colostethus subpunctatus, a tiny frog, protects the egg cluster which is hidden under a stone or log. When the eggs hatch, the male transports the tadpoles on his back, stuck there by a mucous secretion, to a temporary pool where he dips himself into the water and the tadpoles drop off.[110] The male midwife toad (Alytes obstetricans) winds egg strings round his thighs and carries the eggs around for up to eight weeks. He keeps them moist and when they are ready to hatch, he visits a pond or ditch and releases the tadpoles.[111] The female gastric-brooding frog (Rheobatrachus spp.) reared larvae in her stomach after swallowing either the eggs or hatchlings; however, this stage was never observed before the species became extinct. The tadpoles secrete a hormone that inhibits digestion in the mother whilst they develop by consuming their very large yolk supply.[112] The pouched frog (Assa darlingtoni) lays eggs on the ground. When they hatch, the male carries the tadpoles around in brood pouches on his hind legs.[113] The aquatic Surinam toad (Pipa pipa) raises its young in pores on its back where they remain until metamorphosis.[114] The granular poison frog (Oophaga granulifera) is typical of a number of tree frogs in the poison dart frog family Dendrobatidae. Its eggs are laid on the forest floor and when they hatch, the tadpoles are carried one by one on the back of an adult to a suitable water-filled crevice such as the axil of a leaf or the rosette of a bromeliad. The female visits the nursery sites regularly and deposits unfertilised eggs in the water and these are consumed by the tadpoles.[115]
+
+With a few exceptions, adult amphibians are predators, feeding on virtually anything that moves that they can swallow. The diet mostly consists of small prey that do not move too fast such as beetles, caterpillars, earthworms and spiders. The sirens (Siren spp.) often ingest aquatic plant material with the invertebrates on which they feed[116] and a Brazilian tree frog (Xenohyla truncata) includes a large quantity of fruit in its diet.[117] The Mexican burrowing toad (Rhinophrynus dorsalis) has a specially adapted tongue for picking up ants and termites. It projects it with the tip foremost whereas other frogs flick out the rear part first, their tongues being hinged at the front.[118]
+
+Food is mostly selected by sight, even in conditions of dim light. Movement of the prey triggers a feeding response. Frogs have been caught on fish hooks baited with red flannel and green frogs (Rana clamitans) have been found with stomachs full of elm seeds that they had seen floating past.[119] Toads, salamanders and caecilians also use smell to detect prey. This response is mostly secondary because salamanders have been observed to remain stationary near odoriferous prey but only feed if it moves. Cave-dwelling amphibians normally hunt by smell. Some salamanders seem to have learned to recognize immobile prey when it has no smell, even in complete darkness.[120]
+
+Amphibians usually swallow food whole but may chew it lightly first to subdue it.[40] They typically have small hinged pedicellate teeth, a feature unique to amphibians. The base and crown of these are composed of dentine separated by an uncalcified layer and they are replaced at intervals. Salamanders, caecilians and some frogs have one or two rows of teeth in both jaws, but some frogs (Rana spp.) lack teeth in the lower jaw, and toads (Bufo spp.) have no teeth. In many amphibians there are also vomerine teeth attached to a facial bone in the roof of the mouth.[121]
+
+The tiger salamander (Ambystoma tigrinum) is typical of the frogs and salamanders that hide under cover ready to ambush unwary invertebrates. Others amphibians, such as the Bufo spp. toads, actively search for prey, while the Argentine horned frog (Ceratophrys ornata) lures inquisitive prey closer by raising its hind feet over its back and vibrating its yellow toes.[122] Among leaf litter frogs in Panama, frogs that actively hunt prey have narrow mouths and are slim, often brightly coloured and toxic, while ambushers have wide mouths and are broad and well-camouflaged.[123] Caecilians do not flick their tongues, but catch their prey by grabbing it with their slightly backward-pointing teeth. The struggles of the prey and further jaw movements work it inwards and the caecilian usually retreats into its burrow. The subdued prey is gulped down whole.[124]
+
+When they are newly hatched, frog larvae feed on the yolk of the egg. When this is exhausted some move on to feed on bacteria, algal crusts, detritus and raspings from submerged plants. Water is drawn in through their mouths, which are usually at the bottom of their heads, and passes through branchial food traps between their mouths and their gills where fine particles are trapped in mucus and filtered out. Others have specialised mouthparts consisting of a horny beak edged by several rows of labial teeth. They scrape and bite food of many kinds as well as stirring up the bottom sediment, filtering out larger particles with the papillae around their mouths. Some, such as the spadefoot toads, have strong biting jaws and are carnivorous or even cannibalistic.[125]
+
+The calls made by caecilians and salamanders are limited to occasional soft squeaks, grunts or hisses and have not been much studied. A clicking sound sometimes produced by caecilians may be a means of orientation, as in bats, or a form of communication. Most salamanders are considered voiceless, but the California giant salamander (Dicamptodon ensatus) has vocal cords and can produce a rattling or barking sound. Some species of salamander emit a quiet squeak or yelp if attacked.[126]
+
+Frogs are much more vocal, especially during the breeding season when they use their voices to attract mates. The presence of a particular species in an area may be more easily discerned by its characteristic call than by a fleeting glimpse of the animal itself. In most species, the sound is produced by expelling air from the lungs over the vocal cords into an air sac or sacs in the throat or at the corner of the mouth. This may distend like a balloon and acts as a resonator, helping to transfer the sound to the atmosphere, or the water at times when the animal is submerged.[126] The main vocalisation is the male's loud advertisement call which seeks to both encourage a female to approach and discourage other males from intruding on its territory. This call is modified to a quieter courtship call on the approach of a female or to a more aggressive version if a male intruder draws near. Calling carries the risk of attracting predators and involves the expenditure of much energy.[127] Other calls include those given by a female in response to the advertisement call and a release call given by a male or female during unwanted attempts at amplexus. When a frog is attacked, a distress or fright call is emitted, often resembling a scream.[128] The usually nocturnal Cuban tree frog (Osteopilus septentrionalis) produces a rain call when there is rainfall during daylight hours.[129]
+
+Little is known of the territorial behaviour of caecilians, but some frogs and salamanders defend home ranges. These are usually feeding, breeding or sheltering sites. Males normally exhibit such behaviour though in some species, females and even juveniles are also involved. Although in many frog species, females are larger than males, this is not the case in most species where males are actively involved in territorial defence. Some of these have specific adaptations such as enlarged teeth for biting or spines on the chest, arms or thumbs.[130]
+
+In salamanders, defence of a territory involves adopting an aggressive posture and if necessary attacking the intruder. This may involve snapping, chasing and sometimes biting, occasionally causing the loss of a tail. The behaviour of red back salamanders (Plethodon cinereus) has been much studied. 91% of marked individuals that were later recaptured were within a metre (yard) of their original daytime retreat under a log or rock.[131] A similar proportion, when moved experimentally a distance of 30 metres (98 ft), found their way back to their home base.[131] The salamanders left odour marks around their territories which averaged 0.16 to 0.33 square metres (1.7 to 3.6 sq ft) in size and were sometimes inhabited by a male and female pair.[132] These deterred the intrusion of others and delineated the boundaries between neighbouring areas. Much of their behaviour seemed stereotyped and did not involve any actual contact between individuals. An aggressive posture involved raising the body off the ground and glaring at the opponent who often turned away submissively. If the intruder persisted, a biting lunge was usually launched at either the tail region or the naso-labial grooves. Damage to either of these areas can reduce the fitness of the rival, either because of the need to regenerate tissue or because it impairs its ability to detect food.[131]
+
+In frogs, male territorial behaviour is often observed at breeding locations; calling is both an announcement of ownership of part of this resource and an advertisement call to potential mates. In general, a deeper voice represents a heavier and more powerful individual, and this may be sufficient to prevent intrusion by smaller males. Much energy is used in the vocalization and it takes a toll on the territory holder who may be displaced by a fitter rival if he tires. There is a tendency for males to tolerate the holders of neighbouring territories while vigorously attacking unknown intruders. Holders of territories have a "home advantage" and usually come off better in an encounter between two similar-sized frogs. If threats are insufficient, chest to chest tussles may take place. Fighting methods include pushing and shoving, deflating the opponent's vocal sac, seizing him by the head, jumping on his back, biting, chasing, splashing, and ducking him under the water.[133]
+
+Amphibians have soft bodies with thin skins, and lack claws, defensive armour, or spines. Nevertheless, they have evolved various defence mechanisms to keep themselves alive. The first line of defence in salamanders and frogs is the mucous secretion that they produce. This keeps their skin moist and makes them slippery and difficult to grip. The secretion is often sticky and distasteful or toxic.[134] Snakes have been observed yawning and gaping when trying to swallow African clawed frogs (Xenopus laevis), which gives the frogs an opportunity to escape.[134][135] Caecilians have been little studied in this respect, but the Cayenne caecilian (Typhlonectes compressicauda) produces toxic mucus that has killed predatory fish in a feeding experiment in Brazil.[136] In some salamanders, the skin is poisonous. The rough-skinned newt (Taricha granulosa) from North America and other members of its genus contain the neurotoxin tetrodotoxin (TTX), the most toxic non-protein substance known and almost identical to that produced by pufferfish. Handling the newts does not cause harm, but ingestion of even the most minute amounts of the skin is deadly. In feeding trials, fish, frogs, reptiles, birds and mammals were all found to be susceptible.[137][138] The only predators with some tolerance to the poison are certain populations of common garter snake (Thamnophis sirtalis).
+In locations where both snake and salamander co-exist, the snakes have developed immunity through genetic changes and they feed on the amphibians with impunity.[139] Coevolution occurs with the newt increasing its toxic capabilities at the same rate as the snake further develops its immunity.[138] Some frogs and toads are toxic, the main poison glands being at the side of the neck and under the warts on the back. These regions are presented to the attacking animal and their secretions may be foul-tasting or cause various physical or neurological symptoms. Altogether, over 200 toxins have been isolated from the limited number of amphibian species that have been investigated.[140]
+
+Poisonous species often use bright colouring to warn potential predators of their toxicity. These warning colours tend to be red or yellow combined with black, with the fire salamander (Salamandra salamandra) being an example. Once a predator has sampled one of these, it is likely to remember the colouration next time it encounters a similar animal. In some species, such as the fire-bellied toad (Bombina spp.), the warning colouration is on the belly and these animals adopt a defensive pose when attacked, exhibiting their bright colours to the predator. The frog Allobates zaparo is not poisonous, but mimics the appearance of other toxic species in its locality, a strategy that may deceive predators.[142]
+
+Many amphibians are nocturnal and hide during the day, thereby avoiding diurnal predators that hunt by sight. Other amphibians use camouflage to avoid being detected. They have various colourings such as mottled browns, greys and olives to blend into the background. Some salamanders adopt defensive poses when faced by a potential predator such as the North American northern short-tailed shrew (Blarina brevicauda). Their bodies writhe and they raise and lash their tails which makes it difficult for the predator to avoid contact with their poison-producing granular glands.[143] A few salamanders will autotomise their tails when attacked, sacrificing this part of their anatomy to enable them to escape. The tail may have a constriction at its base to allow it to be easily detached. The tail is regenerated later, but the energy cost to the animal of replacing it is significant.[63]
+Some frogs and toads inflate themselves to make themselves look large and fierce, and some spadefoot toads (Pelobates spp) scream and leap towards the attacker.[40] Giant salamanders of the genus Andrias, as well as Ceratophrine and Pyxicephalus frogs possess sharp teeth and are capable of drawing blood with a defensive bite. The blackbelly salamander (Desmognathus quadramaculatus) can bite an attacking common garter snake (Thamnophis sirtalis) two or three times its size on the head and often manages to escape.[144]
+
+In amphibians, there is evidence of habituation, associative learning through both classical and instrumental learning, and discrimination abilities.[145]
+
+In one experiment, when offered live fruit flies (Drosophila virilis), salamanders chose the larger of 1 vs 2 and 2 vs 3. Frogs can distinguish between low numbers (1 vs 2, 2 vs 3, but not 3 vs 4) and large numbers (3 vs 6, 4 vs 8, but not 4 vs 6) of prey. This is irrespective of other characteristics, i.e. surface area, volume, weight and movement, although discrimination among large numbers may be based on surface area.[146]
+
+Dramatic declines in amphibian populations, including population crashes and mass localized extinction, have been noted since the late 1980s from locations all over the world, and amphibian declines are thus perceived to be one of the most critical threats to global biodiversity.[147] In 2004, the International Union for Conservation of Nature (IUCN) reported stating that currently birds,[148] mammals, and amphibians extinction rates were at minimum 48 times greater than natural extinction rates—possibly 1,024 times higher.
+In 2006 there were believed to be 4,035 species of amphibians that depended on water at some stage during their life cycle. Of these, 1,356 (33.6%) were considered to be threatened and this figure is likely to be an underestimate because it excludes 1,427 species for which there was insufficient data to assess their status.[149] A number of causes are believed to be involved, including habitat destruction and modification, over-exploitation, pollution, introduced species, global warming, endocrine-disrupting pollutants, destruction of the ozone layer (ultraviolet radiation has shown to be especially damaging to the skin, eyes, and eggs of amphibians), and diseases like chytridiomycosis. However, many of the causes of amphibian declines are still poorly understood, and are a topic of ongoing discussion.[150]
+
+With their complex reproductive needs and permeable skins, amphibians are often considered to be ecological indicators.[151] In many terrestrial ecosystems, they constitute one of the largest parts of the vertebrate biomass. Any decline in amphibian numbers will affect the patterns of predation. The loss of carnivorous species near the top of the food chain will upset the delicate ecosystem balance and may cause dramatic increases in opportunistic species. In the Middle East, a growing appetite for eating frog legs and the consequent gathering of them for food was linked to an increase in mosquitoes.[152] Predators that feed on amphibians are affected by their decline. The western terrestrial garter snake (Thamnophis elegans) in California is largely aquatic and depends heavily on two species of frog that are decreasing in numbers, the Yosemite toad (Bufo canorus) and the mountain yellow-legged frog (Rana muscosa), putting the snake's future at risk. If the snake were to become scarce, this would affect birds of prey and other predators that feed on it.[153] Meanwhile, in the ponds and lakes, fewer frogs means fewer tadpoles. These normally play an important role in controlling the growth of algae and also forage on detritus that accumulates as sediment on the bottom. A reduction in the number of tadpoles may lead to an overgrowth of algae, resulting in depletion of oxygen in the water when the algae later die and decompose. Aquatic invertebrates and fish might then die and there would be unpredictable ecological consequences.[154]
+
+A global strategy to stem the crisis was released in 2005 in the form of the Amphibian Conservation Action Plan. Developed by over eighty leading experts in the field, this call to action details what would be required to curtail amphibian declines and extinctions over the following five years and how much this would cost. The Amphibian Specialist Group of the IUCN is spearheading efforts to implement a comprehensive global strategy for amphibian conservation.[155] Amphibian Ark is an organization that was formed to implement the ex-situ conservation recommendations of this plan, and they have been working with zoos and aquaria around the world, encouraging them to create assurance colonies of threatened amphibians.[155] One such project is the Panama Amphibian Rescue and Conservation Project that built on existing conservation efforts in Panama to create a country-wide response to the threat of chytridiomycosis.[156]
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+A forest is a large area of land dominated by trees.[1]  Hundreds of more precise definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing and ecological function.[2][3][4] According to the widely used[5][6] Food and Agriculture Organization definition, forests covered 4 billion hectares (9.9×109 acres) (15 million square miles) or approximately 30 percent of the world's land area in 2006.[4]
+
+Forests are the dominant terrestrial ecosystem of Earth, and are distributed around the globe.[7] Forests account for 75% of the gross primary production of the Earth's biosphere, and contain 80% of the Earth's plant biomass. Net primary production is estimated at 21.9 gigatonnes carbon per year for tropical forests, 8.1 for temperate forests, and 2.6 for boreal forests.[7]
+
+Forests at different latitudes and elevations form distinctly different ecozones: boreal forests around the poles, tropical forests around the Equator, and temperate forests at the middle latitudes. Higher elevation areas tend to support forests similar to those at higher latitudes, and amount of precipitation also affects forest composition.
+
+Human society and forests influence each other in both positive and negative ways.[8] Forests provide ecosystem services to humans and serve as tourist attractions. Forests can also affect people's health. Human activities, including harvesting forest resources, can negatively affect forest ecosystems.[citation needed]
+
+Although the word forest is commonly used, there is no universally recognised precise definition, with more than 800 definitions of forest used around the world.[4] Although a forest is usually defined by the presence of trees, under many definitions an area completely lacking trees may still be considered a forest if it grew trees in the past, will grow trees in the future,[9] or was legally designated as a forest regardless of vegetation type.[10][11]
+
+There are three broad categories of forest definitions in use: administrative, land use, and land cover.[10] Administrative definitions are based primarily upon the legal designations of land, and commonly bear little relationship to the vegetation growing on the land: land that is legally designated as a forest is defined as a forest even if no trees are growing on it.[10] Land use definitions are based upon the primary purpose that the land serves. For example, a forest may be defined as any land that is used primarily for production of timber. Under such a land use definition, cleared roads or infrastructure within an area used for forestry, or areas within the region that have been cleared by harvesting, disease or fire are still considered forests even if they contain no trees. Land cover definitions define forests based upon the type and density of vegetation growing on the land. Such definitions typically define a forest as an area growing trees above some threshold. These thresholds are typically the number of trees per area (density), the area of ground under the tree canopy (canopy cover) or the section of land that is occupied by the cross-section of tree trunks (basal area).[10] Under such land cover definitions, an area of land can only be known as forest if it is growing trees. Areas that fail to meet the land cover definition may be still included under while immature trees are establishing if they are expected to meet the definition at maturity.[10]
+
+Under land use definitions, there is considerable variation on where the cutoff points are between a forest, woodland, and savanna. Under some definitions, forests require very high levels of tree canopy cover, from 60% to 100%,[12] excluding savannas and woodlands in which trees have a lower canopy cover. Other definitions consider savannas to be a type of forest, and include all areas with tree canopies over 10%.[9]
+
+Some areas covered with trees are legally defined as agricultural areas, e.g. Norway spruce plantations in Austrian forest law when the trees are being grown as Christmas trees and below a certain height.
+
+The word forest derives from the Old French forest (also forès), denoting "forest, vast expanse covered by trees"; forest was first introduced into English as the word denoting wild land set aside for hunting[14] without the necessity in definition of having trees on the land.[15] Possibly a borrowing, probably via Frankish or Old High German, of the Medieval Latin foresta, denoting "open wood", Carolingian scribes first used foresta in the Capitularies of Charlemagne specifically to denote the royal hunting grounds of the King. The word was not endemic to Romance languages, e. g. native words for forest in the Romance languages derived from the Latin silva, which denoted "forest" and "wood(land)" (confer the English sylva and sylvan); confer the Italian, Spanish, and Portuguese selva; the Romanian silvă; and the Old French selve, and cognates in Romance languages, e. g. the Italian foresta, Spanish and Portuguese floresta, etc., are all ultimately derivations of the French word.
+
+The precise origin of Medieval Latin foresta is obscure. Some authorities claim the word derives from the Late Latin phrase forestam silvam, denoting "the outer wood"; others claim the word is a latinisation of the Frankish *forhist, denoting "forest, wooded country", and was assimilated to "forestam silvam" pursuant to the common practice of Frankish scribes. The Old High German forst denoting "forest", Middle Low German vorst denoting "forest", Old English fyrhþ denoting "forest, woodland, game preserve, hunting ground" (English frith), and Old Norse fýri, denoting "coniferous forest", all of which derive from the Proto-Germanic *furhísa-, *furhíþija-, denoting "a fir-wood, coniferous forest", from the Proto-Indo-European *perkwu-, denoting "a coniferous or mountain forest, wooded height" all attest to the Frankish *forhist.
+
+Uses of forest in English to denote any uninhabited and unenclosed area presently are considered archaic.[16] The Norman rulers of England introduced the word as a legal term, as seen in Latin texts such as the Magna Carta, to denote uncultivated land that was legally designated for hunting by feudal nobility (see Royal Forest).[16][17]
+
+These hunting forests did not necessarily contain many, if any, trees. However, because hunting forests often included significant areas of woodland, forest eventually came to connote woodland in general, regardless of the density of the trees.[citation needed] By the beginning of the Fourteenth Century, English texts used the word in all three of its senses: common, legal, and archaic.[16] Other English words used to denote "an area with a high density of trees" are firth, frith, holt, weald, wold, wood, and woodland. Unlike forest, these are all derived from Old English and were not borrowed from another language. Some present classifications reserve woodland for denoting a locale with more open space between trees, and distinguish kinds of woodlands as open forests and closed forests premised on their crown covers.[18] Finally, sylva (plural sylvae or, less classically, sylvas) is a peculiar English spelling of the Latin silva, denoting a "woodland", and has precedent in English, including its plural forms. While its use as a synonym of forest and as a Latinate word denoting a woodland may be admitted, in a specific technical sense it is restricted to denoting the species of trees that comprise the woodlands of a region, as in its sense in the subject of silviculture.[19] The resorting to sylva in English indicates more precisely the denotation that use of forest intends.
+
+The first known forests on Earth arose in the Late Devonian (approximately 380 million years ago), with the evolution of Archaeopteris.[20] Archaeopteris was a plant that was both tree-like and fern-like, growing to 10 metres (33 ft) in height. Archaeopteris quickly spread throughout the world, from the equator to subpolar latitudes.[20] Archaeopteris formed the first forest by being the first known species to cast shade due to its fronds and forming soil from its roots. Archaeopteris was deciduous, dropping its fronds onto the forest floor. The shade, soil, and forest duff from the dropped fronds created the first forest.[20] The shed organic matter altered the freshwater environment, slowing it down and providing food. This promoted freshwater fish.[20]
+
+
+
+Forests account for 75% of the gross primary productivity of the Earth's biosphere, and contain 80% of the Earth's plant biomass.[7] Forest ecosystems can be found in all regions capable of sustaining tree growth, at altitudes up to the tree line, except where natural fire frequency or other disturbance is too high, or where the environment has been altered by human activity.
+
+The latitudes 10° north and south of the equator are mostly covered in tropical rainforest, and the latitudes between 53°N and 67°N have boreal forest. As a general rule, forests dominated by angiosperms (broadleaf forests) are more species-rich than those dominated by gymnosperms (conifer, montane, or needleleaf forests), although exceptions exist.
+
+Forests sometimes contain many tree species within a small area (as in tropical rain and temperate deciduous forests), or relatively few species over large areas (e.g., taiga and arid montane coniferous forests). Forests are often home to many animal and plant species, and biomass per unit area is high compared to other vegetation communities. Much of this biomass occurs below ground in the root systems and as partially decomposed plant detritus. The woody component of a forest contains lignin, which is relatively slow to decompose compared with other organic materials such as cellulose or carbohydrate.
+
+A forest consists of many components that can be broadly divided into two categories that are biotic (living) and abiotic (non-living) components. The living parts include trees, shrubs, vines, grasses and other herbaceous (non-woody) plants, mosses, algae, fungi, insects, mammals, birds, reptiles, amphibians, and microorganisms living on the plants and animals and in the soil.
+
+A forest is made up of many layers. The main layers of all forest types are the forest floor, the understory and the canopy. The emergent layer exists in tropical rainforests. Each layer has a different set of plants and animals depending upon the availability of sunlight, moisture and food.
+
+However, in botany and many countries (Germany, Poland, etc.), a different classification of forest vegetation structure is often used: tree, shrub, herb and moss layers, see stratification (vegetation).
+
+
+
+Forests can be classified in different ways and to different degrees of specificity. One such way is in terms of the biome in which they exist, combined with leaf longevity of the dominant species (whether they are evergreen or deciduous). Another distinction is whether the forests are composed predominantly of broadleaf trees, coniferous (needle-leaved) trees, or mixed.
+
+The number of trees in the world, according to a 2015 estimate, is 3 trillion, of which 1.4 trillion are in the tropics or sub-tropics, 0.6 trillion in the temperate zones, and 0.7 trillion in the coniferous boreal forests. The estimate is about eight times higher than previous estimates, and is based on tree densities measured on over 400,000 plots. It remains subject to a wide margin of error, not least because the samples are mainly from Europe and North America.[22]
+
+Forests can also be classified according to the amount of human alteration. Old-growth forest contains mainly natural patterns of biodiversity in established seral patterns, and they contain mainly species native to the region and habitat. In contrast, secondary forest is regrowing forest following timber harvest and may contain species originally from other regions or habitats.[23]
+
+Different global forest classification systems have been proposed, but none has gained universal acceptance.[24] UNEP-WCMC's forest category classification system is a simplification of other more complex systems (e.g. UNESCO's forest and woodland 'subformations'). This system divides the world's forests into 26 major types, which reflect climatic zones as well as the principal types of trees. These 26 major types can be reclassified into 6 broader categories: temperate needleleaf; temperate broadleaf and mixed; tropical moist; tropical dry; sparse trees and parkland; and forest plantations.[24] Each category is described as a separate section below.
+
+Temperate needleleaf forests mostly occupy the higher latitude regions of the Northern Hemisphere, as well as high altitude zones and some warm temperate areas, especially on nutrient-poor or otherwise unfavourable soils. These forests are composed entirely, or nearly so, of coniferous species (Coniferophyta). In the Northern Hemisphere pines Pinus, spruces Picea, larches Larix, firs Abies, Douglas firs Pseudotsuga and hemlocks Tsuga, make up the canopy, but other taxa are also important. In the Southern Hemisphere, most coniferous trees (members of the Araucariaceae and Podocarpaceae) occur in mixtures with broadleaf species, and are classed as broadleaf and mixed forests.[24]
+
+Temperate broadleaf and mixed forests include a substantial component of trees in the Anthophyta. They are generally characteristic of the warmer temperate latitudes, but extend to cool temperate ones, particularly in the southern hemisphere. They include such forest types as the mixed deciduous forests of the United States and their counterparts in China and Japan, the broadleaf evergreen rainforests of Japan, Chile and Tasmania, the sclerophyllous forests of Australia, central Chile, the Mediterranean and California, and the southern beech Nothofagus forests of Chile and New Zealand.[24]
+
+There are many different types of tropical moist forests, with lowland evergreen broad leaf tropical rainforests, for example várzea and igapó forests and the terra firma forests of the Amazon Basin; the peat swamp forests, dipterocarp forests of Southeast Asia; and the high forests of the Congo Basin.  Seasonal tropical forests, perhaps the best description for the colloquial term "jungle", typically range from the rainforest zone 10 degrees north or south of the equator, to the Tropic of Cancer and Tropic of Capricorn. Forests located on mountains are also included in this category, divided largely into upper and lower montane formations on the basis of the variation of physiognomy corresponding to changes in altitude.[25]
+
+Tropical dry forests are characteristic of areas in the tropics affected by seasonal drought. The seasonality of rainfall is usually reflected in the deciduousness of the forest canopy, with most trees being leafless for several months of the year. However, under some conditions, e.g. less fertile soils or less predictable drought regimes, the proportion of evergreen species increases and the forests are characterised as "sclerophyllous". Thorn forest, a dense forest of low stature with a high frequency of thorny or spiny species, is found where drought is prolonged, and especially where grazing animals are plentiful. On very poor soils, and especially where fire or herbivory are recurrent phenomena, savannas develop.[24]
+
+Sparse trees and savanna are forests with lower canopy cover of trees. They occur principally in areas of transition from forested to non-forested landscapes. The two major zones in which these ecosystems occur are in the boreal region and in the seasonally dry tropics. At high latitudes, north of the main zone of boreal forest, growing conditions are not adequate to maintain a continuous closed forest cover, so tree cover is both sparse and discontinuous. This vegetation is variously called open taiga, open lichen woodland, and forest tundra. A savanna is a mixed woodland grassland ecosystem characterized by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of grasses. Savannas maintain an open canopy despite a high tree density.[24]
+
+Forest plantations are generally intended for the production of timber and pulpwood. Commonly mono-specific and/or composed of introduced tree species, these ecosystems are not generally important as habitat for native biodiversity. However, they can be managed in ways that enhance their biodiversity protection functions and they can provide ecosystem services such as maintaining nutrient capital, protecting watersheds and soil structure, and storing carbon.[23][24]
+
+Forests provide a diversity of ecosystem services including:
+
+Some researchers state that forests do not only provide benefits, but can in certain cases also incur costs to humans.[29][30] Forests may impose an economic burden,[31][32] diminish the enjoyment of natural areas,[33] reduce the food producing capacity of grazing land [34] and cultivated land,[35] reduce biodiversity [36][37] reduce available water for humans and wildlife,[38][39] harbour dangerous or destructive wildlife,[29][40] and act as reservoirs of human and livestock disease.[41][42]
+
+The management of forests is often referred to as forestry. Forest management has changed considerably over the last few centuries, with rapid changes from the 1980s onwards culminating in a practice now referred to as sustainable forest management. Forest ecologists concentrate on forest patterns and processes, usually with the aim of elucidating cause-and-effect relationships. Foresters who practice sustainable forest management focus on the integration of ecological, social, and economic values, often in consultation with local communities and other stakeholders.
+
+Humans have generally decreased the amount of forest worldwide. Anthropogenic factors that can affect forests include logging, urban sprawl, human-caused forest fires, acid rain, invasive species, and the slash and burn practices of swidden agriculture or shifting cultivation. The loss and re-growth of forest leads to a distinction between two broad types of forest, primary or old-growth forest and secondary forest. There are also many natural factors that can cause changes in forests over time including forest fires, insects, diseases, weather, competition between species, etc. In 1997, the World Resources Institute recorded that only 20% of the world's original forests remained in large intact tracts of undisturbed forest.[43] More than 75% of these intact forests lie in three countries—the boreal forests of Russia and Canada and the rainforest of Brazil.
+
+In 2010, the United Nations Food and Agriculture Organization[44] reported that world deforestation, mainly the conversion of tropical forests to agricultural land, had decreased over the past ten years but still continues at a high rate in many countries. Globally, around 13 million hectares of forests were converted to other uses or lost through natural causes each year between 2000 and 2010 as compared to around 16 million hectares per year during the 1990s. The study covered 233 countries and areas. Brazil and Indonesia, which had the highest loss of forests in the 1990s, have significantly reduced their deforestation rates. China instituted a ban on logging, beginning in 1998, due to the erosion and flooding that it caused.[45] In addition, ambitious tree planting programmes in countries such as China, India, the United States and Vietnam – combined with natural expansion of forests in some regions – have added more than seven million hectares of new forests annually. As a result, the net loss of forest area was reduced to 5.2 million hectares per year between 2000 and 2010, down from 8.3 million hectares annually in the 1990s. In 2015, a study for Nature Climate Change showed that the trend has recently been reversed, leading to an "overall gain" in global biomass and forests. This gain is due especially to reforestation in China and Russia.[46] However new forests are not completely equivalent to old growth forests in terms of species diversity, resilience and carbon capture.
+On September 7, 2015, the Food and Agriculture Organization of the United Nations released a new study stating that, over the last 25 years, the global deforestation rate has decreased by 50% due to improved management of forests and greater government protection.[47][48]
+
+Smaller areas of woodland in cities may be managed as urban forestry, sometimes within public parks. These are often created for human benefits; Attention Restoration Theory argues that spending time in nature reduces stress and improves health, while forest schools and kindergartens help young people to develop social as well as scientific skills in forests. These typically need to be close to where the children live, for practical logistics.
+
+Canada has about 4,020,000 square kilometres (1,550,000 sq mi) of forest land. More than 90% of forest land is publicly owned and about 50% of the total forest area is allocated for harvesting. These allocated areas are managed using the principles of sustainable forest management, which includes extensive consultation with local stakeholders. About eight percent of Canada's forest is legally protected from resource development.[49][50]  Much more forest land—about 40 percent of the total forest land base—is subject to varying degrees of protection through processes such as integrated land use planning or defined management areas such as certified forests.[50]
+
+By December 2006, over 1,237,000 square kilometres of forest land in Canada (about half the global total) had been certified as being sustainably managed.[51] Clearcutting, first used in the latter half of the 20th century, is less expensive, but devastating to the environment, and companies are required by law to ensure that harvested areas are adequately regenerated. Most Canadian provinces have regulations limiting the size of clear-cuts, although some older clear-cuts can range upwards of 110 square kilometres (27,000 acres) in size which was cut over several years.
+
+Latvia has about 3,270,000 hectares (12,626 sq mi) of forest land which equates to 50.6% of Latvia's total area (24,938 sq mi). 1,510,000 hectares of forest land (46.3% of total forest land) is publicly owned and 1,750,000 hectares of forest land (53.7% of total forest land) is in private hands. Latvia's forests have been steadily increasing over the years which is in contrast to many other nations, mostly due to the forestation of land not used for agriculture. In 1935 there was only 1,757,000 hectares of forest, today this has increased by more than 150%. Birch is the most common tree at 28.2% followed by pine (26,9%), spruce (18.3%), grey alder (9.7%), aspen (8,0%), black alder (5.7%), oak/ash (1.2%) and finally hardwood making up the rest (2.0%).[52][53]
+
+In the United States, most forests have historically been affected by humans to some degree, though in recent years improved forestry practices have helped regulate or moderate large scale or severe impacts. However, the United States Forest Service estimates a net loss of about 2 million hectares (4,942,000 acres) between 1997 and 2020; this estimate includes conversion of forest land to other uses, including urban and suburban development, as well as afforestation and natural reversion of abandoned crop and pasture land to forest. However, in many areas of the United States, the area of forest is stable or increasing, particularly in many northern states. The opposite problem from flooding has plagued national forests, with loggers complaining that a lack of thinning and proper forest management has resulted in large forest fires.[54][55]
+

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+
+
+A forest is a large area of land dominated by trees.[1]  Hundreds of more precise definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing and ecological function.[2][3][4] According to the widely used[5][6] Food and Agriculture Organization definition, forests covered 4 billion hectares (9.9×109 acres) (15 million square miles) or approximately 30 percent of the world's land area in 2006.[4]
+
+Forests are the dominant terrestrial ecosystem of Earth, and are distributed around the globe.[7] Forests account for 75% of the gross primary production of the Earth's biosphere, and contain 80% of the Earth's plant biomass. Net primary production is estimated at 21.9 gigatonnes carbon per year for tropical forests, 8.1 for temperate forests, and 2.6 for boreal forests.[7]
+
+Forests at different latitudes and elevations form distinctly different ecozones: boreal forests around the poles, tropical forests around the Equator, and temperate forests at the middle latitudes. Higher elevation areas tend to support forests similar to those at higher latitudes, and amount of precipitation also affects forest composition.
+
+Human society and forests influence each other in both positive and negative ways.[8] Forests provide ecosystem services to humans and serve as tourist attractions. Forests can also affect people's health. Human activities, including harvesting forest resources, can negatively affect forest ecosystems.[citation needed]
+
+Although the word forest is commonly used, there is no universally recognised precise definition, with more than 800 definitions of forest used around the world.[4] Although a forest is usually defined by the presence of trees, under many definitions an area completely lacking trees may still be considered a forest if it grew trees in the past, will grow trees in the future,[9] or was legally designated as a forest regardless of vegetation type.[10][11]
+
+There are three broad categories of forest definitions in use: administrative, land use, and land cover.[10] Administrative definitions are based primarily upon the legal designations of land, and commonly bear little relationship to the vegetation growing on the land: land that is legally designated as a forest is defined as a forest even if no trees are growing on it.[10] Land use definitions are based upon the primary purpose that the land serves. For example, a forest may be defined as any land that is used primarily for production of timber. Under such a land use definition, cleared roads or infrastructure within an area used for forestry, or areas within the region that have been cleared by harvesting, disease or fire are still considered forests even if they contain no trees. Land cover definitions define forests based upon the type and density of vegetation growing on the land. Such definitions typically define a forest as an area growing trees above some threshold. These thresholds are typically the number of trees per area (density), the area of ground under the tree canopy (canopy cover) or the section of land that is occupied by the cross-section of tree trunks (basal area).[10] Under such land cover definitions, an area of land can only be known as forest if it is growing trees. Areas that fail to meet the land cover definition may be still included under while immature trees are establishing if they are expected to meet the definition at maturity.[10]
+
+Under land use definitions, there is considerable variation on where the cutoff points are between a forest, woodland, and savanna. Under some definitions, forests require very high levels of tree canopy cover, from 60% to 100%,[12] excluding savannas and woodlands in which trees have a lower canopy cover. Other definitions consider savannas to be a type of forest, and include all areas with tree canopies over 10%.[9]
+
+Some areas covered with trees are legally defined as agricultural areas, e.g. Norway spruce plantations in Austrian forest law when the trees are being grown as Christmas trees and below a certain height.
+
+The word forest derives from the Old French forest (also forès), denoting "forest, vast expanse covered by trees"; forest was first introduced into English as the word denoting wild land set aside for hunting[14] without the necessity in definition of having trees on the land.[15] Possibly a borrowing, probably via Frankish or Old High German, of the Medieval Latin foresta, denoting "open wood", Carolingian scribes first used foresta in the Capitularies of Charlemagne specifically to denote the royal hunting grounds of the King. The word was not endemic to Romance languages, e. g. native words for forest in the Romance languages derived from the Latin silva, which denoted "forest" and "wood(land)" (confer the English sylva and sylvan); confer the Italian, Spanish, and Portuguese selva; the Romanian silvă; and the Old French selve, and cognates in Romance languages, e. g. the Italian foresta, Spanish and Portuguese floresta, etc., are all ultimately derivations of the French word.
+
+The precise origin of Medieval Latin foresta is obscure. Some authorities claim the word derives from the Late Latin phrase forestam silvam, denoting "the outer wood"; others claim the word is a latinisation of the Frankish *forhist, denoting "forest, wooded country", and was assimilated to "forestam silvam" pursuant to the common practice of Frankish scribes. The Old High German forst denoting "forest", Middle Low German vorst denoting "forest", Old English fyrhþ denoting "forest, woodland, game preserve, hunting ground" (English frith), and Old Norse fýri, denoting "coniferous forest", all of which derive from the Proto-Germanic *furhísa-, *furhíþija-, denoting "a fir-wood, coniferous forest", from the Proto-Indo-European *perkwu-, denoting "a coniferous or mountain forest, wooded height" all attest to the Frankish *forhist.
+
+Uses of forest in English to denote any uninhabited and unenclosed area presently are considered archaic.[16] The Norman rulers of England introduced the word as a legal term, as seen in Latin texts such as the Magna Carta, to denote uncultivated land that was legally designated for hunting by feudal nobility (see Royal Forest).[16][17]
+
+These hunting forests did not necessarily contain many, if any, trees. However, because hunting forests often included significant areas of woodland, forest eventually came to connote woodland in general, regardless of the density of the trees.[citation needed] By the beginning of the Fourteenth Century, English texts used the word in all three of its senses: common, legal, and archaic.[16] Other English words used to denote "an area with a high density of trees" are firth, frith, holt, weald, wold, wood, and woodland. Unlike forest, these are all derived from Old English and were not borrowed from another language. Some present classifications reserve woodland for denoting a locale with more open space between trees, and distinguish kinds of woodlands as open forests and closed forests premised on their crown covers.[18] Finally, sylva (plural sylvae or, less classically, sylvas) is a peculiar English spelling of the Latin silva, denoting a "woodland", and has precedent in English, including its plural forms. While its use as a synonym of forest and as a Latinate word denoting a woodland may be admitted, in a specific technical sense it is restricted to denoting the species of trees that comprise the woodlands of a region, as in its sense in the subject of silviculture.[19] The resorting to sylva in English indicates more precisely the denotation that use of forest intends.
+
+The first known forests on Earth arose in the Late Devonian (approximately 380 million years ago), with the evolution of Archaeopteris.[20] Archaeopteris was a plant that was both tree-like and fern-like, growing to 10 metres (33 ft) in height. Archaeopteris quickly spread throughout the world, from the equator to subpolar latitudes.[20] Archaeopteris formed the first forest by being the first known species to cast shade due to its fronds and forming soil from its roots. Archaeopteris was deciduous, dropping its fronds onto the forest floor. The shade, soil, and forest duff from the dropped fronds created the first forest.[20] The shed organic matter altered the freshwater environment, slowing it down and providing food. This promoted freshwater fish.[20]
+
+
+
+Forests account for 75% of the gross primary productivity of the Earth's biosphere, and contain 80% of the Earth's plant biomass.[7] Forest ecosystems can be found in all regions capable of sustaining tree growth, at altitudes up to the tree line, except where natural fire frequency or other disturbance is too high, or where the environment has been altered by human activity.
+
+The latitudes 10° north and south of the equator are mostly covered in tropical rainforest, and the latitudes between 53°N and 67°N have boreal forest. As a general rule, forests dominated by angiosperms (broadleaf forests) are more species-rich than those dominated by gymnosperms (conifer, montane, or needleleaf forests), although exceptions exist.
+
+Forests sometimes contain many tree species within a small area (as in tropical rain and temperate deciduous forests), or relatively few species over large areas (e.g., taiga and arid montane coniferous forests). Forests are often home to many animal and plant species, and biomass per unit area is high compared to other vegetation communities. Much of this biomass occurs below ground in the root systems and as partially decomposed plant detritus. The woody component of a forest contains lignin, which is relatively slow to decompose compared with other organic materials such as cellulose or carbohydrate.
+
+A forest consists of many components that can be broadly divided into two categories that are biotic (living) and abiotic (non-living) components. The living parts include trees, shrubs, vines, grasses and other herbaceous (non-woody) plants, mosses, algae, fungi, insects, mammals, birds, reptiles, amphibians, and microorganisms living on the plants and animals and in the soil.
+
+A forest is made up of many layers. The main layers of all forest types are the forest floor, the understory and the canopy. The emergent layer exists in tropical rainforests. Each layer has a different set of plants and animals depending upon the availability of sunlight, moisture and food.
+
+However, in botany and many countries (Germany, Poland, etc.), a different classification of forest vegetation structure is often used: tree, shrub, herb and moss layers, see stratification (vegetation).
+
+
+
+Forests can be classified in different ways and to different degrees of specificity. One such way is in terms of the biome in which they exist, combined with leaf longevity of the dominant species (whether they are evergreen or deciduous). Another distinction is whether the forests are composed predominantly of broadleaf trees, coniferous (needle-leaved) trees, or mixed.
+
+The number of trees in the world, according to a 2015 estimate, is 3 trillion, of which 1.4 trillion are in the tropics or sub-tropics, 0.6 trillion in the temperate zones, and 0.7 trillion in the coniferous boreal forests. The estimate is about eight times higher than previous estimates, and is based on tree densities measured on over 400,000 plots. It remains subject to a wide margin of error, not least because the samples are mainly from Europe and North America.[22]
+
+Forests can also be classified according to the amount of human alteration. Old-growth forest contains mainly natural patterns of biodiversity in established seral patterns, and they contain mainly species native to the region and habitat. In contrast, secondary forest is regrowing forest following timber harvest and may contain species originally from other regions or habitats.[23]
+
+Different global forest classification systems have been proposed, but none has gained universal acceptance.[24] UNEP-WCMC's forest category classification system is a simplification of other more complex systems (e.g. UNESCO's forest and woodland 'subformations'). This system divides the world's forests into 26 major types, which reflect climatic zones as well as the principal types of trees. These 26 major types can be reclassified into 6 broader categories: temperate needleleaf; temperate broadleaf and mixed; tropical moist; tropical dry; sparse trees and parkland; and forest plantations.[24] Each category is described as a separate section below.
+
+Temperate needleleaf forests mostly occupy the higher latitude regions of the Northern Hemisphere, as well as high altitude zones and some warm temperate areas, especially on nutrient-poor or otherwise unfavourable soils. These forests are composed entirely, or nearly so, of coniferous species (Coniferophyta). In the Northern Hemisphere pines Pinus, spruces Picea, larches Larix, firs Abies, Douglas firs Pseudotsuga and hemlocks Tsuga, make up the canopy, but other taxa are also important. In the Southern Hemisphere, most coniferous trees (members of the Araucariaceae and Podocarpaceae) occur in mixtures with broadleaf species, and are classed as broadleaf and mixed forests.[24]
+
+Temperate broadleaf and mixed forests include a substantial component of trees in the Anthophyta. They are generally characteristic of the warmer temperate latitudes, but extend to cool temperate ones, particularly in the southern hemisphere. They include such forest types as the mixed deciduous forests of the United States and their counterparts in China and Japan, the broadleaf evergreen rainforests of Japan, Chile and Tasmania, the sclerophyllous forests of Australia, central Chile, the Mediterranean and California, and the southern beech Nothofagus forests of Chile and New Zealand.[24]
+
+There are many different types of tropical moist forests, with lowland evergreen broad leaf tropical rainforests, for example várzea and igapó forests and the terra firma forests of the Amazon Basin; the peat swamp forests, dipterocarp forests of Southeast Asia; and the high forests of the Congo Basin.  Seasonal tropical forests, perhaps the best description for the colloquial term "jungle", typically range from the rainforest zone 10 degrees north or south of the equator, to the Tropic of Cancer and Tropic of Capricorn. Forests located on mountains are also included in this category, divided largely into upper and lower montane formations on the basis of the variation of physiognomy corresponding to changes in altitude.[25]
+
+Tropical dry forests are characteristic of areas in the tropics affected by seasonal drought. The seasonality of rainfall is usually reflected in the deciduousness of the forest canopy, with most trees being leafless for several months of the year. However, under some conditions, e.g. less fertile soils or less predictable drought regimes, the proportion of evergreen species increases and the forests are characterised as "sclerophyllous". Thorn forest, a dense forest of low stature with a high frequency of thorny or spiny species, is found where drought is prolonged, and especially where grazing animals are plentiful. On very poor soils, and especially where fire or herbivory are recurrent phenomena, savannas develop.[24]
+
+Sparse trees and savanna are forests with lower canopy cover of trees. They occur principally in areas of transition from forested to non-forested landscapes. The two major zones in which these ecosystems occur are in the boreal region and in the seasonally dry tropics. At high latitudes, north of the main zone of boreal forest, growing conditions are not adequate to maintain a continuous closed forest cover, so tree cover is both sparse and discontinuous. This vegetation is variously called open taiga, open lichen woodland, and forest tundra. A savanna is a mixed woodland grassland ecosystem characterized by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of grasses. Savannas maintain an open canopy despite a high tree density.[24]
+
+Forest plantations are generally intended for the production of timber and pulpwood. Commonly mono-specific and/or composed of introduced tree species, these ecosystems are not generally important as habitat for native biodiversity. However, they can be managed in ways that enhance their biodiversity protection functions and they can provide ecosystem services such as maintaining nutrient capital, protecting watersheds and soil structure, and storing carbon.[23][24]
+
+Forests provide a diversity of ecosystem services including:
+
+Some researchers state that forests do not only provide benefits, but can in certain cases also incur costs to humans.[29][30] Forests may impose an economic burden,[31][32] diminish the enjoyment of natural areas,[33] reduce the food producing capacity of grazing land [34] and cultivated land,[35] reduce biodiversity [36][37] reduce available water for humans and wildlife,[38][39] harbour dangerous or destructive wildlife,[29][40] and act as reservoirs of human and livestock disease.[41][42]
+
+The management of forests is often referred to as forestry. Forest management has changed considerably over the last few centuries, with rapid changes from the 1980s onwards culminating in a practice now referred to as sustainable forest management. Forest ecologists concentrate on forest patterns and processes, usually with the aim of elucidating cause-and-effect relationships. Foresters who practice sustainable forest management focus on the integration of ecological, social, and economic values, often in consultation with local communities and other stakeholders.
+
+Humans have generally decreased the amount of forest worldwide. Anthropogenic factors that can affect forests include logging, urban sprawl, human-caused forest fires, acid rain, invasive species, and the slash and burn practices of swidden agriculture or shifting cultivation. The loss and re-growth of forest leads to a distinction between two broad types of forest, primary or old-growth forest and secondary forest. There are also many natural factors that can cause changes in forests over time including forest fires, insects, diseases, weather, competition between species, etc. In 1997, the World Resources Institute recorded that only 20% of the world's original forests remained in large intact tracts of undisturbed forest.[43] More than 75% of these intact forests lie in three countries—the boreal forests of Russia and Canada and the rainforest of Brazil.
+
+In 2010, the United Nations Food and Agriculture Organization[44] reported that world deforestation, mainly the conversion of tropical forests to agricultural land, had decreased over the past ten years but still continues at a high rate in many countries. Globally, around 13 million hectares of forests were converted to other uses or lost through natural causes each year between 2000 and 2010 as compared to around 16 million hectares per year during the 1990s. The study covered 233 countries and areas. Brazil and Indonesia, which had the highest loss of forests in the 1990s, have significantly reduced their deforestation rates. China instituted a ban on logging, beginning in 1998, due to the erosion and flooding that it caused.[45] In addition, ambitious tree planting programmes in countries such as China, India, the United States and Vietnam – combined with natural expansion of forests in some regions – have added more than seven million hectares of new forests annually. As a result, the net loss of forest area was reduced to 5.2 million hectares per year between 2000 and 2010, down from 8.3 million hectares annually in the 1990s. In 2015, a study for Nature Climate Change showed that the trend has recently been reversed, leading to an "overall gain" in global biomass and forests. This gain is due especially to reforestation in China and Russia.[46] However new forests are not completely equivalent to old growth forests in terms of species diversity, resilience and carbon capture.
+On September 7, 2015, the Food and Agriculture Organization of the United Nations released a new study stating that, over the last 25 years, the global deforestation rate has decreased by 50% due to improved management of forests and greater government protection.[47][48]
+
+Smaller areas of woodland in cities may be managed as urban forestry, sometimes within public parks. These are often created for human benefits; Attention Restoration Theory argues that spending time in nature reduces stress and improves health, while forest schools and kindergartens help young people to develop social as well as scientific skills in forests. These typically need to be close to where the children live, for practical logistics.
+
+Canada has about 4,020,000 square kilometres (1,550,000 sq mi) of forest land. More than 90% of forest land is publicly owned and about 50% of the total forest area is allocated for harvesting. These allocated areas are managed using the principles of sustainable forest management, which includes extensive consultation with local stakeholders. About eight percent of Canada's forest is legally protected from resource development.[49][50]  Much more forest land—about 40 percent of the total forest land base—is subject to varying degrees of protection through processes such as integrated land use planning or defined management areas such as certified forests.[50]
+
+By December 2006, over 1,237,000 square kilometres of forest land in Canada (about half the global total) had been certified as being sustainably managed.[51] Clearcutting, first used in the latter half of the 20th century, is less expensive, but devastating to the environment, and companies are required by law to ensure that harvested areas are adequately regenerated. Most Canadian provinces have regulations limiting the size of clear-cuts, although some older clear-cuts can range upwards of 110 square kilometres (27,000 acres) in size which was cut over several years.
+
+Latvia has about 3,270,000 hectares (12,626 sq mi) of forest land which equates to 50.6% of Latvia's total area (24,938 sq mi). 1,510,000 hectares of forest land (46.3% of total forest land) is publicly owned and 1,750,000 hectares of forest land (53.7% of total forest land) is in private hands. Latvia's forests have been steadily increasing over the years which is in contrast to many other nations, mostly due to the forestation of land not used for agriculture. In 1935 there was only 1,757,000 hectares of forest, today this has increased by more than 150%. Birch is the most common tree at 28.2% followed by pine (26,9%), spruce (18.3%), grey alder (9.7%), aspen (8,0%), black alder (5.7%), oak/ash (1.2%) and finally hardwood making up the rest (2.0%).[52][53]
+
+In the United States, most forests have historically been affected by humans to some degree, though in recent years improved forestry practices have helped regulate or moderate large scale or severe impacts. However, the United States Forest Service estimates a net loss of about 2 million hectares (4,942,000 acres) between 1997 and 2020; this estimate includes conversion of forest land to other uses, including urban and suburban development, as well as afforestation and natural reversion of abandoned crop and pasture land to forest. However, in many areas of the United States, the area of forest is stable or increasing, particularly in many northern states. The opposite problem from flooding has plagued national forests, with loggers complaining that a lack of thinning and proper forest management has resulted in large forest fires.[54][55]
+

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@@ -0,0 +1,238 @@
+
+
+
+
+Martialinae
+
+Leptanillinae
+
+Amblyoponinae
+
+Paraponerinae
+
+Agroecomyrmecinae
+
+Ponerinae
+
+Proceratiinae
+
+Ecitoninae‡
+
+Aenictinae‡
+
+Dorylini‡
+
+Aenictogitoninae‡
+
+Cerapachyinae‡*
+
+Leptanilloidinae‡
+
+Dolichoderinae
+
+Aneuretinae
+
+Pseudomyrmecinae
+
+Myrmeciinae
+
+Ectatomminae
+
+Heteroponerinae
+
+Myrmicinae
+
+Formicinae
+
+A phylogeny of the extant ant subfamilies.[2][3]
+*Cerapachyinae is paraphyletic
+‡ The previous dorylomorph subfamilies were synonymized under Dorylinae by Brady et al. in 2014[4]
+
+Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants appear in the fossil record across the globe in considerable diversity during the latest Early Cretaceous and early Late Cretaceous, suggesting an earlier origin. Ants evolved from vespoid wasp ancestors in the Cretaceous period, and diversified after the rise of flowering plants. More than 12,500 of an estimated total of 22,000 species have been classified. They are easily identified by their elbowed antennae and the distinctive node-like structure that forms their slender waists.
+
+Ants form colonies that range in size from a few dozen predatory individuals living in small natural cavities to highly organised colonies that may occupy large territories and consist of millions of individuals. Larger colonies consist of various castes of sterile, wingless females, most of which are workers (ergates), as well as soldiers (dinergates) and other specialised groups. Nearly all ant colonies also have some fertile males called "drones" (aner) and one or more fertile females called "queens" (gynes). The colonies are described as superorganisms because the ants appear to operate as a unified entity, collectively working together to support the colony.
+
+Ants have colonised almost every landmass on Earth. The only places lacking indigenous ants are Antarctica and a few remote or inhospitable islands. Ants thrive in most ecosystems and may form 15–25% of the terrestrial animal biomass. Their success in so many environments has been attributed to their social organisation and their ability to modify habitats, tap resources, and defend themselves. Their long co-evolution with other species has led to mimetic, commensal, parasitic, and mutualistic relationships.
+
+Ant societies have division of labour, communication between individuals, and an ability to solve complex problems. These parallels with human societies have long been an inspiration and subject of study. Many human cultures make use of ants in cuisine, medication, and rituals. Some species are valued in their role as biological pest control agents. Their ability to exploit resources may bring ants into conflict with humans, however, as they can damage crops and invade buildings. Some species, such as the red imported fire ant (Solenopsis invicta), are regarded as invasive species, establishing themselves in areas where they have been introduced accidentally.
+
+The word ant and its chiefly dialectal form emmet[5] come from ante, emete of Middle English, which come from ǣmette of Old English, and these are all related to the dialectal Dutch emt and the Old High German āmeiza, from which comes the modern German Ameise. All of these words come from West Germanic *ǣmaitjōn, and the original meaning of the word was "the biter" (from Proto-Germanic *ai-, "off, away" + *mait- "cut").[6][7] The family name Formicidae is derived from the Latin formīca ("ant")[8] from which the words in other Romance languages, such as the Portuguese formiga, Italian formica, Spanish hormiga, Romanian furnică, and French fourmi are derived. It has been hypothesised that a Proto-Indo-European word *morwi- was used, cf. Sanskrit vamrah, Latin formīca, Greek μύρμηξ mýrmēx, Old Church Slavonic mraviji, Old Irish moirb, Old Norse maurr, Dutch mier.[9]
+
+Chrysidoidea
+
+Vespidae
+
+Rhopalosomatidae
+
+Pompilidae
+
+Tiphiidae
+
+Scolioidea
+
+Apoidea
+
+Formicidae
+
+The family Formicidae belongs to the order Hymenoptera, which also includes sawflies, bees, and wasps. Ants evolved from a lineage within the stinging wasps, and a 2013 study suggests that they are a sister group of the Apoidea.[10] In 1966, E. O. Wilson and his colleagues identified the fossil remains of an ant (Sphecomyrma) that lived in the Cretaceous period. The specimen, trapped in amber dating back to around 92 million years ago, has features found in some wasps, but not found in modern ants.[11] Sphecomyrma was possibly a ground forager, while Haidomyrmex and Haidomyrmodes, related genera in subfamily Sphecomyrminae, are reconstructed as active arboreal predators.[12] Older ants in the genus Sphecomyrmodes have been found in 99 million year-old amber from Myanmar.[13][14] A 2006 study suggested that ants arose tens of millions of years earlier than previously thought, up to 168 million years ago.[1] After the rise of flowering plants about 100 million years ago they diversified and assumed ecological dominance around 60 million years ago.[15][1][16][17] Some groups, such as the Leptanillinae and Martialinae, are suggested to have diversified from early primitive ants that were likely to have been predators underneath the surface of the soil.[3][18]
+
+During the Cretaceous period, a few species of primitive ants ranged widely on the Laurasian supercontinent (the Northern Hemisphere). They were scarce in comparison to the populations of other insects, representing only about 1% of the entire insect population. Ants became dominant after adaptive radiation at the beginning of the Paleogene period. By the Oligocene and Miocene, ants had come to represent 20–40% of all insects found in major fossil deposits. Of the species that lived in the Eocene epoch, around one in 10 genera survive to the present. Genera surviving today comprise 56% of the genera in Baltic amber fossils (early Oligocene), and 92% of the genera in Dominican amber fossils (apparently early Miocene).[15][19]
+
+Termites live in colonies and are sometimes called ‘white ants’, but termites are not ants. They are the sub-order Isoptera, and together with cockroaches they form the order Blattodea. Blattodeans are related to mantids, crickets, and other winged insects that do not undergo full metamorphosis. Like ants, termites are eusocial, with sterile workers, but they differ greatly in the genetics of reproduction. The similarity of their social structure to that of ants is attributed to convergent evolution.[20] Velvet ants look like large ants, but are wingless female wasps.[21][22]
+
+Ants are found on all continents except Antarctica, and only a few large islands, such as Greenland, Iceland, parts of Polynesia and the Hawaiian Islands lack native ant species.[24][25] Ants occupy a wide range of ecological niches and exploit many different food resources as direct or indirect herbivores, predators and scavengers. Most ant species are omnivorous generalists, but a few are specialist feeders. Their ecological dominance is demonstrated by their biomass: ants are estimated to contribute 15–20 % (on average and nearly 25% in the tropics) of terrestrial animal biomass, exceeding that of the vertebrates.[26]
+
+Ants range in size from 0.75 to 52 millimetres (0.030–2.0 in),[27][28] the largest species being the fossil Titanomyrma giganteum, the queen of which was 6 centimetres (2.4 in) long with a wingspan of 15 centimetres (5.9 in).[29] Ants vary in colour; most ants are red or black, but a few species are green and some tropical species have a metallic lustre. More than 12,000 species are currently known (with upper estimates of the potential existence of about 22,000) (see the article List of ant genera), with the greatest diversity in the tropics. Taxonomic studies continue to resolve the classification and systematics of ants. Online databases of ant species, including AntBase and the Hymenoptera Name Server, help to keep track of the known and newly described species.[30] The relative ease with which ants may be sampled and studied in ecosystems has made them useful as indicator species in biodiversity studies.[31][32]
+
+Ants are distinct in their morphology from other insects in having elbowed antennae, metapleural glands, and a strong constriction of their second abdominal segment into a node-like petiole. The head, mesosoma, and metasoma are the three distinct body segments (formally tagmata). The petiole forms a narrow waist between their mesosoma (thorax plus the first abdominal segment, which is fused to it) and gaster (abdomen less the abdominal segments in the petiole). The petiole may be formed by one or two nodes (the second alone, or the second and third abdominal segments).[33]
+
+Like other insects, ants have an exoskeleton, an external covering that provides a protective casing around the body and a point of attachment for muscles, in contrast to the internal skeletons of humans and other vertebrates. Insects do not have lungs; oxygen and other gases, such as carbon dioxide, pass through their exoskeleton via tiny valves called spiracles. Insects also lack closed blood vessels; instead, they have a long, thin, perforated tube along the top of the body (called the "dorsal aorta") that functions like a heart, and pumps haemolymph toward the head, thus driving the circulation of the internal fluids. The nervous system consists of a ventral nerve cord that runs the length of the body, with several ganglia and branches along the way reaching into the extremities of the appendages.[34]
+
+An ant's head contains many sensory organs. Like most insects, ants have compound eyes made from numerous tiny lenses attached together. Ant eyes are good for acute movement detection, but do not offer a high resolution image. They also have three small ocelli (simple eyes) on the top of the head that detect light levels and polarization.[35] Compared to vertebrates, ants tend to have blurrier eyesight, particularly in smaller species,[36] and a few subterranean taxa are completely blind.[2] However, some ants, such as Australia's bulldog ant, have excellent vision and are capable of discriminating the distance and size of objects moving nearly a metre away.[37]
+
+Two antennae ("feelers") are attached to the head; these organs detect chemicals, air currents, and vibrations; they also are used to transmit and receive signals through touch. The head has two strong jaws, the mandibles, used to carry food, manipulate objects, construct nests, and for defence.[34] In some species, a small pocket (infrabuccal chamber) inside the mouth stores food, so it may be passed to other ants or their larvae.[38]
+
+Both the legs and wings of the ant are attached to the mesosoma ("thorax"). The legs terminate in a hooked claw which allows them to hook on and climb surfaces.[39] Only reproductive ants, queens, and males, have wings. Queens shed their wings after the nuptial flight, leaving visible stubs, a distinguishing feature of queens. In a few species, wingless queens (ergatoids) and males occur.[34]
+
+The metasoma (the "abdomen") of the ant houses important internal organs, including those of the reproductive, respiratory (tracheae), and excretory systems. Workers of many species have their egg-laying structures modified into stings that are used for subduing prey and defending their nests.[34]
+
+In the colonies of a few ant species, there are physical castes—workers in distinct size-classes, called minor, median, and major ergates. Often, the larger ants have disproportionately larger heads, and correspondingly stronger mandibles. These are known as macrergates while smaller workers are known as micrergates.[40] Although formally known as dinergates, such individuals are sometimes called "soldier" ants because their stronger mandibles make them more effective in fighting, although they still are workers and their "duties" typically do not vary greatly from the minor or median workers. In a few species, the median workers are absent, creating a sharp divide between the minors and majors.[41] Weaver ants, for example, have a distinct bimodal size distribution.[42][43] Some other species show continuous variation in the size of workers. The smallest and largest workers in Pheidologeton diversus show nearly a 500-fold difference in their dry-weights.[44]
+
+Workers cannot mate; however, because of the haplodiploid sex-determination system in ants, workers of a number of species can lay unfertilised eggs that become fully fertile, haploid males. The role of workers may change with their age and in some species, such as honeypot ants, young workers are fed until their gasters are distended, and act as living food storage vessels. These food storage workers are called repletes.[45] For instance, these replete workers develop in the North American honeypot ant Myrmecocystus mexicanus. Usually the largest workers in the colony develop into repletes; and, if repletes are removed from the colony, other workers become repletes, demonstrating the flexibility of this particular polymorphism.[46] This polymorphism in morphology and behaviour of workers initially was thought to be determined by environmental factors such as nutrition and hormones that led to different developmental paths; however, genetic differences between worker castes have been noted in Acromyrmex sp.[47] These polymorphisms are caused by relatively small genetic changes; differences in a single gene of Solenopsis invicta can decide whether the colony will have single or multiple queens.[48] The Australian jack jumper ant (Myrmecia pilosula) has only a single pair of chromosomes (with the males having just one chromosome as they are haploid), the lowest number known for any animal, making it an interesting subject for studies in the genetics and developmental biology of social insects.[49][50]
+
+The life of an ant starts from an egg; if the egg is fertilised, the progeny will be female diploid, if not, it will be male haploid. Ants develop by complete metamorphosis with the larva stages passing through a pupal stage before emerging as an adult. The larva is largely immobile and is fed and cared for by workers. Food is given to the larvae by trophallaxis, a process in which an ant regurgitates liquid food held in its crop. This is also how adults share food, stored in the "social stomach". Larvae, especially in the later stages, may also be provided solid food, such as trophic eggs, pieces of prey, and seeds brought by workers.[51]
+
+The larvae grow through a series of four or five moults and enter the pupal stage. The pupa has the appendages free and not fused to the body as in a butterfly pupa.[52] The differentiation into queens and workers (which are both female), and different castes of workers, is influenced in some species by the nutrition the larvae obtain. Genetic influences and the control of gene expression by the developmental environment are complex and the determination of caste continues to be a subject of research.[53] Winged male ants, called drones, emerge from pupae along with the usually winged breeding females. Some species, such as army ants, have wingless queens. Larvae and pupae need to be kept at fairly constant temperatures to ensure proper development, and so often are moved around among the various brood chambers within the colony.[54]
+
+A new ergate spends the first few days of its adult life caring for the queen and young. She then graduates to digging and other nest work, and later to defending the nest and foraging. These changes are sometimes fairly sudden, and define what are called temporal castes. An explanation for the sequence is suggested by the high casualties involved in foraging, making it an acceptable risk only for ants who are older and are likely to die soon of natural causes.[55][56]
+
+Ant colonies can be long-lived. The queens can live for up to 30 years, and workers live from 1 to 3 years. Males, however, are more transitory, being quite short-lived and surviving for only a few weeks.[57] Ant queens are estimated to live 100 times as long as solitary insects of a similar size.[58]
+
+Ants are active all year long in the tropics, but, in cooler regions, they survive the winter in a state of dormancy known as hibernation. The forms of inactivity are varied and some temperate species have larvae going into the inactive state (diapause), while in others, the adults alone pass the winter in a state of reduced activity.[59]
+
+A wide range of reproductive strategies have been noted in ant species. Females of many species are known to be capable of reproducing asexually through thelytokous parthenogenesis.[60] Secretions from the male accessory glands in some species can plug the female genital opening and prevent females from re-mating.[61] Most ant species have a system in which only the queen and breeding females have the ability to mate. Contrary to popular belief, some ant nests have multiple queens, while others may exist without queens. Workers with the ability to reproduce are called "gamergates" and colonies that lack queens are then called gamergate colonies; colonies with queens are said to be queen-right.[62]
+
+Drones can also mate with existing queens by entering a foreign colony. When the drone is initially attacked by the workers, it releases a mating pheromone. If recognized as a mate, it will be carried to the queen to mate.[63] Males may also patrol the nest and fight others by grabbing them with their mandibles, piercing their exoskeleton and then marking them with a pheromone. The marked male is interpreted as an invader by worker ants and is killed.[64]
+
+Most ants are univoltine, producing a new generation each year.[65] During the species-specific breeding period, winged females and winged males, known to entomologists as alates, leave the colony in what is called a nuptial flight. The nuptial flight usually takes place in the late spring or early summer when the weather is hot and humid. Heat makes flying easier and freshly fallen rain makes the ground softer for mated queens to dig nests.[66] Males typically take flight before the females. Males then use visual cues to find a common mating ground, for example, a landmark such as a pine tree to which other males in the area converge. Males secrete a mating pheromone that females follow. Males will mount females in the air, but the actual mating process usually takes place on the ground. Females of some species mate with just one male but in others they may mate with as many as ten or more different males, storing the sperm in their spermathecae.[67]
+
+Mated females then seek a suitable place to begin a colony. There, they break off their wings and begin to lay and care for eggs. The females can selectively fertilise future eggs with the sperm stored to produce diploid workers or lay unfertilized haploid eggs to produce drones. The first workers to hatch are known as nanitics,[68] and are weaker and smaller than later workers, but they begin to serve the colony immediately. They enlarge the nest, forage for food, and care for the other eggs. Species that have multiple queens may have a queen leaving the nest along with some workers to found a colony at a new site,[67] a process akin to swarming in honeybees.
+
+Ants communicate with each other using pheromones, sounds, and touch.[69] The use of pheromones as chemical signals is more developed in ants, such as the red harvester ant, than in other hymenopteran groups. Like other insects, ants perceive smells with their long, thin, and mobile antennae. The paired antennae provide information about the direction and intensity of scents. Since most ants live on the ground, they use the soil surface to leave pheromone trails that may be followed by other ants. In species that forage in groups, a forager that finds food marks a trail on the way back to the colony; this trail is followed by other ants, these ants then reinforce the trail when they head back with food to the colony. When the food source is exhausted, no new trails are marked by returning ants and the scent slowly dissipates. This behaviour helps ants deal with changes in their environment. For instance, when an established path to a food source is blocked by an obstacle, the foragers leave the path to explore new routes. If an ant is successful, it leaves a new trail marking the shortest route on its return. Successful trails are followed by more ants, reinforcing better routes and gradually identifying the best path.[70]
+
+Ants use pheromones for more than just making trails. A crushed ant emits an alarm pheromone that sends nearby ants into an attack frenzy and attracts more ants from farther away. Several ant species even use "propaganda pheromones" to confuse enemy ants and make them fight among themselves.[71] Pheromones are produced by a wide range of structures including Dufour's glands, poison glands and glands on the hindgut, pygidium, rectum, sternum, and hind tibia.[58] Pheromones also are exchanged, mixed with food, and passed by trophallaxis, transferring information within the colony.[72] This allows other ants to detect what task group (e.g., foraging or nest maintenance) other colony members belong to.[73] In ant species with queen castes, when the dominant queen stops producing a specific pheromone, workers begin to raise new queens in the colony.[74]
+
+Some ants produce sounds by stridulation, using the gaster segments and their mandibles. Sounds may be used to communicate with colony members or with other species.[75][76]
+
+Ants attack and defend themselves by biting and, in many species, by stinging, often injecting or spraying chemicals, such as formic acid in the case of formicine ants, alkaloids and piperidines in fire ants, and a variety of protein components in other ants. Bullet ants (Paraponera), located in Central and South America, are considered to have the most painful sting of any insect, although it is usually not fatal to humans. This sting is given the highest rating on the Schmidt sting pain index.[77]
+
+The sting of jack jumper ants can be fatal,[78] and an antivenom has been developed for it.[79]
+
+Fire ants, Solenopsis spp., are unique in having a venom sac containing piperidine alkaloids.[80] Their stings are painful and can be dangerous to hypersensitive people.[81]
+
+Trap-jaw ants of the genus Odontomachus are equipped with mandibles called trap-jaws, which snap shut faster than any other predatory appendages within the animal kingdom.[82] One study of Odontomachus bauri recorded peak speeds of between 126 and 230 km/h (78 and 143 mph), with the jaws closing within 130 microseconds on average.
+The ants were also observed to use their jaws as a catapult to eject intruders or fling themselves backward to escape a threat.[82] Before striking, the ant opens its mandibles extremely widely and locks them in this position by an internal mechanism. Energy is stored in a thick band of muscle and explosively released when triggered by the stimulation of sensory organs resembling hairs on the inside of the mandibles. The mandibles also permit slow and fine movements for other tasks. Trap-jaws also are seen in the following genera: Anochetus, Orectognathus, and Strumigenys,[82] plus some members of the Dacetini tribe,[83] which are viewed as examples of convergent evolution.
+
+A Malaysian species of ant in the Camponotus cylindricus group has enlarged mandibular glands that extend into their gaster. If combat takes a turn for the worse, a worker may perform a final act of suicidal altruism by rupturing the membrane of its gaster, causing the content of its mandibular glands to burst from the anterior region of its head, spraying a poisonous, corrosive secretion containing acetophenones and other chemicals that immobilise small insect attackers. The worker subsequently dies.[84]
+
+Suicidal defences by workers are also noted in a Brazilian ant, Forelius pusillus, where a small group of ants leaves the security of the nest after sealing the entrance from the outside each evening.[85]
+
+In addition to defence against predators, ants need to protect their colonies from pathogens. Some worker ants maintain the hygiene of the colony and their activities include undertaking or necrophory, the disposal of dead nest-mates.[86] Oleic acid has been identified as the compound released from dead ants that triggers necrophoric behaviour in Atta mexicana[87] while workers of Linepithema humile react to the absence of characteristic chemicals (dolichodial and iridomyrmecin) present on the cuticle of their living nestmates to trigger similar behaviour.[88]
+
+Nests may be protected from physical threats such as flooding and overheating by elaborate nest architecture.[89][90] Workers of Cataulacus muticus, an arboreal species that lives in plant hollows, respond to flooding by drinking water inside the nest, and excreting it outside.[91] Camponotus anderseni, which nests in the cavities of wood in mangrove habitats, deals with submergence under water by switching to anaerobic respiration.[92]
+
+Many animals can learn behaviours by imitation, but ants may be the only group apart from mammals where interactive teaching has been observed. A knowledgeable forager of Temnothorax albipennis can lead a naïve nest-mate to newly discovered food by the process of tandem running. The follower obtains knowledge through its leading tutor. The leader is acutely sensitive to the progress of the follower and slows down when the follower lags and speeds up when the follower gets too close.[93]
+
+Controlled experiments with colonies of Cerapachys biroi suggest that an individual may choose nest roles based on her previous experience. An entire generation of identical workers was divided into two groups whose outcome in food foraging was controlled. One group was continually rewarded with prey, while it was made certain that the other failed. As a result, members of the successful group intensified their foraging attempts while the unsuccessful group ventured out fewer and fewer times. A month later, the successful foragers continued in their role while the others had moved to specialise in brood care.[94]
+
+Complex nests are built by many ant species, but other species are nomadic and do not build permanent structures. Ants may form subterranean nests or build them on trees. These nests may be found in the ground, under stones or logs, inside logs, hollow stems, or even acorns. The materials used for construction include soil and plant matter,[67] and ants carefully select their nest sites; Temnothorax albipennis will avoid sites with dead ants, as these may indicate the presence of pests or disease. They are quick to abandon established nests at the first sign of threats.[95]
+
+The army ants of South America, such as the Eciton burchellii species, and the driver ants of Africa do not build permanent nests, but instead, alternate between nomadism and stages where the workers form a temporary nest (bivouac) from their own bodies, by holding each other together.[96]
+
+Weaver ant (Oecophylla spp.) workers build nests in trees by attaching leaves together, first pulling them together with bridges of workers and then inducing their larvae to produce silk as they are moved along the leaf edges. Similar forms of nest construction are seen in some species of Polyrhachis.[97]
+
+Formica polyctena, among other ant species, constructs nests that maintain a relatively constant interior temperature that aids in the development of larvae. The ants maintain the nest temperature by choosing the location, nest materials, controlling ventilation and maintaining the heat from solar radiation, worker activity and metabolism, and in some moist nests, microbial activity in the nest materials.[98]
+
+Some ant species, such as those that use natural cavities, can be opportunistic and make use of the controlled micro-climate provided inside human dwellings and other artificial structures to house their colonies and nest structures.[99][100]
+
+Most ants are generalist predators, scavengers, and indirect herbivores,[16] but a few have evolved specialised ways of obtaining nutrition. It is believed that many ant species that engage in indirect herbivory rely on specialized symbiosis with their gut microbes [101] to upgrade the nutritional value of the food they collect [102] and allow them to survive in nitrogen poor regions, such as rainforest canopies.[103] Leafcutter ants (Atta and Acromyrmex) feed exclusively on a fungus that grows only within their colonies. They continually collect leaves which are taken to the colony, cut into tiny pieces and placed in fungal gardens. Ergates specialise in related tasks according to their sizes. The largest ants cut stalks, smaller workers chew the leaves and the smallest tend the fungus. Leafcutter ants are sensitive enough to recognise the reaction of the fungus to different plant material, apparently detecting chemical signals from the fungus. If a particular type of leaf is found to be toxic to the fungus, the colony will no longer collect it. The ants feed on structures produced by the fungi called gongylidia. Symbiotic bacteria on the exterior surface of the ants produce antibiotics that kill bacteria introduced into the nest that may harm the fungi.[104]
+
+Foraging ants travel distances of up to 200 metres (700 ft) from their nest [105] and scent trails allow them to find their way back even in the dark. In hot and arid regions, day-foraging ants face death by desiccation, so the ability to find the shortest route back to the nest reduces that risk. Diurnal desert ants of the genus Cataglyphis such as the Sahara desert ant navigate by keeping track of direction as well as distance travelled. Distances travelled are measured using an internal pedometer that keeps count of the steps taken[106] and also by evaluating the movement of objects in their visual field (optical flow).[107] Directions are measured using the position of the sun.[108]
+They integrate this information to find the shortest route back to their nest.[109]
+Like all ants, they can also make use of visual landmarks when available[110] as well as olfactory and tactile cues to navigate.[111][112] Some species of ant are able to use the Earth's magnetic field for navigation.[113] The compound eyes of ants have specialised cells that detect polarised light from the Sun, which is used to determine direction.[114][115]
+These polarization detectors are sensitive in the ultraviolet region of the light spectrum.[116] In some army ant species, a group of foragers who become separated from the main column may sometimes turn back on themselves and form a circular ant mill. The workers may then run around continuously until they die of exhaustion.[117]
+
+The female worker ants do not have wings and reproductive females lose their wings after their mating flights in order to begin their colonies. Therefore, unlike their wasp ancestors, most ants travel by walking. Some species are capable of leaping. For example, Jerdon's jumping ant (Harpegnathos saltator) is able to jump by synchronising the action of its mid and hind pairs of legs.[118] There are several species of gliding ant including Cephalotes atratus; this may be a common trait among arboreal ants with small colonies. Ants with this ability are able to control their horizontal movement so as to catch tree trunks when they fall from atop the forest canopy.[119]
+
+Other species of ants can form chains to bridge gaps over water, underground, or through spaces in vegetation. Some species also form floating rafts that help them survive floods.[120]  These rafts may also have a role in allowing ants to colonise islands.[121] Polyrhachis sokolova, a species of ant found in Australian mangrove swamps, can swim and live in underwater nests. Since they lack gills, they go to trapped pockets of air in the submerged nests to breathe.[122]
+
+Not all ants have the same kind of societies. The Australian bulldog ants are among the biggest and most basal of ants. Like virtually all ants, they are eusocial, but their social behaviour is poorly developed compared to other species. Each individual hunts alone, using her large eyes instead of chemical senses to find prey.[123]
+
+Some species (such as Tetramorium caespitum) attack and take over neighbouring ant colonies. Others are less expansionist, but just as aggressive; they invade colonies to steal eggs or larvae, which they either eat or raise as workers or slaves. Extreme specialists among these slave-raiding ants, such as the Amazon ants, are incapable of feeding themselves and need captured workers to survive.[124] Captured workers of enslaved Temnothorax species have evolved a counter strategy, destroying just the female pupae of the slave-making Temnothorax americanus, but sparing the males (who don't take part in slave-raiding as adults).[125]
+
+Ants identify kin and nestmates through their scent, which comes from hydrocarbon-laced secretions that coat their exoskeletons. If an ant is separated from its original colony, it will eventually lose the colony scent. Any ant that enters a colony without a matching scent will be attacked.[126] Also, the reason why two separate colonies of ants will attack each other even if they are of the same species is because the genes responsible for pheromone production are different between them. The Argentine ant, however, does not have this characteristic, due to lack of genetic diversity, and has become a global pest because of it.
+
+Parasitic ant species enter the colonies of host ants and establish themselves as social parasites; species such as Strumigenys xenos are entirely parasitic and do not have workers, but instead, rely on the food gathered by their Strumigenys perplexa hosts.[127][128] This form of parasitism is seen across many ant genera, but the parasitic ant is usually a species that is closely related to its host. A variety of methods are employed to enter the nest of the host ant. A parasitic queen may enter the host nest before the first brood has hatched, establishing herself prior to development of a colony scent. Other species use pheromones to confuse the host ants or to trick them into carrying the parasitic queen into the nest. Some simply fight their way into the nest.[129]
+
+A conflict between the sexes of a species is seen in some species of ants with these reproducers apparently competing to produce offspring that are as closely related to them as possible. The most extreme form involves the production of clonal offspring. An extreme of sexual conflict is seen in Wasmannia auropunctata, where the queens produce diploid daughters by thelytokous parthenogenesis and males produce clones by a process whereby a diploid egg loses its maternal contribution to produce haploid males who are clones of the father.[130]
+
+Ants form symbiotic associations with a range of species, including other ant species, other insects, plants, and fungi. They also are preyed on by many animals and even certain fungi. Some arthropod species spend part of their lives within ant nests, either preying on ants, their larvae, and eggs, consuming the food stores of the ants, or avoiding predators. These inquilines may bear a close resemblance to ants. The nature of this ant mimicry (myrmecomorphy) varies, with some cases involving Batesian mimicry, where the mimic reduces the risk of predation. Others show Wasmannian mimicry, a form of mimicry seen only in inquilines.[131][132]
+
+Aphids and other hemipteran insects secrete a sweet liquid called honeydew, when they feed on plant sap. The sugars in honeydew are a high-energy food source, which many ant species collect.[133] In some cases, the aphids secrete the honeydew in response to ants tapping them with their antennae. The ants in turn keep predators away from the aphids and will move them from one feeding location to another. When migrating to a new area, many colonies will take the aphids with them, to ensure a continued supply of honeydew. Ants also tend mealybugs to harvest their honeydew. Mealybugs may become a serious pest of pineapples if ants are present to protect mealybugs from their natural enemies.[134]
+
+Myrmecophilous (ant-loving) caterpillars of the butterfly family Lycaenidae (e.g., blues, coppers, or hairstreaks) are herded by the ants, led to feeding areas in the daytime, and brought inside the ants' nest at night. The caterpillars have a gland which secretes honeydew when the ants massage them. Some caterpillars produce vibrations and sounds that are perceived by the ants.[135] A similar adaptation can be seen in Grizzled skipper butterflies that emit vibrations by expanding their wings in order to communicate with ants, which are natural predators of these butterflies.[136] Other caterpillars have evolved from ant-loving to ant-eating: these myrmecophagous caterpillars secrete a pheromone that makes the ants act as if the caterpillar is one of their own larvae. The caterpillar is then taken into the ant nest where it feeds on the ant larvae.[137] A number of specialized bacterial have been found as endosymbionts in ant guts. Some of the dominant bacteria belong to the order Rhizobiales whose members are known for being nitrogen-fixing symbionts in legumes but the species found in ant lack the ability to fix nitrogen.[138][139] Fungus-growing ants that make up the tribe Attini, including leafcutter ants, cultivate certain species of fungus in the genera Leucoagaricus or Leucocoprinus of the family Agaricaceae. In this ant-fungus mutualism, both species depend on each other for survival. The ant Allomerus decemarticulatus has evolved a three-way association with the host plant, Hirtella physophora (Chrysobalanaceae), and a sticky fungus which is used to trap their insect prey.[140]
+
+Lemon ants make devil's gardens by killing surrounding plants with their stings and leaving a pure patch of lemon ant trees, (Duroia hirsuta). This modification of the forest provides the ants with more nesting sites inside the stems of the Duroia trees.[141] Although some ants obtain nectar from flowers, pollination by ants is somewhat rare, one example being of the pollination of the orchid Leporella fimbriata which induces male Myrmecia urens to pseudocopulate with the flowers, transferring pollen in the process.[142] One theory that has been proposed for the rarity of pollination is that the secretions of the metapleural gland inactivate and reduce the viability of pollen.[143][144] Some plants have special nectar exuding structures, extrafloral nectaries, that provide food for ants, which in turn protect the plant from more damaging herbivorous insects.[145] Species such as the bullhorn acacia (Acacia cornigera) in Central America have hollow thorns that house colonies of stinging ants (Pseudomyrmex ferruginea) who defend the tree against insects, browsing mammals, and epiphytic vines. Isotopic labelling studies suggest that plants also obtain nitrogen from the ants.[146] In return, the ants obtain food from protein- and lipid-rich Beltian bodies. In Fiji Philidris nagasau (Dolichoderinae) are known to selectively grow species of epiphytic Squamellaria (Rubiaceae) which produce large domatia inside which the ant colonies nest. The ants plant the seeds and the domatia of young seedling are immediately occupied and the ant faeces in them contribute to rapid growth.[147] Similar dispersal associations are found with other dolichoderines in the region as well.[148] Another example of this type of ectosymbiosis comes from the Macaranga tree, which has stems adapted to house colonies of Crematogaster ants.[149]
+
+Many plant species have seeds that are adapted for dispersal by ants.[150] Seed dispersal by ants or myrmecochory is widespread, and new estimates suggest that nearly 9% of all plant species may have such ant associations.[151][150] Often, seed-dispersing ants perform directed dispersal, depositing the seeds in locations that increase the likelihood of seed survival to reproduction.[152] Some plants in arid, fire-prone systems are particularly dependent on ants for their survival and dispersal as the seeds are transported to safety below the ground.[153] Many ant-dispersed seeds have special external structures, elaiosomes, that are sought after by ants as food.[154]
+
+A convergence, possibly a form of mimicry, is seen in the eggs of stick insects. They have an edible elaiosome-like structure and are taken into the ant nest where the young hatch.[155]
+
+Most ants are predatory and some prey on and obtain food from other social insects including other ants. Some species specialise in preying on termites (Megaponera and Termitopone) while a few Cerapachyinae prey on other ants.[105] Some termites, including Nasutitermes corniger, form associations with certain ant species to keep away predatory ant species.[156] The tropical wasp Mischocyttarus drewseni coats the pedicel of its nest with an ant-repellent chemical.[157] It is suggested that many tropical wasps may build their nests in trees and cover them to protect themselves from ants. Other wasps, such as A. multipicta, defend against ants by blasting them off the nest with bursts of wing buzzing.[158] Stingless bees (Trigona and Melipona) use chemical defences against ants.[105]
+
+Flies in the Old World genus Bengalia (Calliphoridae) prey on ants and are kleptoparasites, snatching prey or brood from the mandibles of adult ants.[159] Wingless and legless females of the Malaysian phorid fly (Vestigipoda myrmolarvoidea) live in the nests of ants of the genus Aenictus and are cared for by the ants.[159]
+
+Fungi in the genera Cordyceps and Ophiocordyceps infect ants. Ants react to their infection by climbing up plants and sinking their mandibles into plant tissue. The fungus kills the ants, grows on their remains, and produces a fruiting body. It appears that the fungus alters the behaviour of the ant to help disperse its spores [160] in a microhabitat that best suits the fungus.[161] Strepsipteran parasites also manipulate their ant host to climb grass stems, to help the parasite find mates.[162]
+
+A nematode (Myrmeconema neotropicum) that infects canopy ants (Cephalotes atratus) causes the black-coloured gasters of workers to turn red. The parasite also alters the behaviour of the ant, causing them to carry their gasters high. The conspicuous red gasters are mistaken by birds for ripe fruits, such as Hyeronima alchorneoides, and eaten. The droppings of the bird are collected by other ants and fed to their young, leading to further spread of the nematode.[163]
+
+South American poison dart frogs in the genus Dendrobates feed mainly on ants, and the toxins in their skin may come from the ants.[164]
+
+Army ants forage in a wide roving column, attacking any animals in that path that are unable to escape. In Central and South America, Eciton burchellii is the swarming ant most commonly attended by "ant-following" birds such as antbirds and woodcreepers.[165][166] This behaviour was once considered mutualistic, but later studies found the birds to be parasitic. Direct kleptoparasitism (birds stealing food from the ants' grasp) is rare and has been noted in Inca doves which pick seeds at nest entrances as they are being transported by species of Pogonomyrmex.[167] Birds that follow ants eat many prey insects and thus decrease the foraging success of ants.[168] Birds indulge in a peculiar behaviour called anting that, as yet, is not fully understood. Here birds rest on ant nests, or pick and drop ants onto their wings and feathers; this may be a means to remove ectoparasites from the birds.
+
+Anteaters, aardvarks, pangolins, echidnas and numbats have special adaptations for living on a diet of ants. These adaptations include long, sticky tongues to capture ants and strong claws to break into ant nests. Brown bears (Ursus arctos) have been found to feed on ants. About 12%, 16%, and 4% of their faecal volume in spring, summer, and autumn, respectively, is composed of ants.[169]
+
+Ants perform many ecological roles that are beneficial to humans, including the suppression of pest populations and aeration of the soil. The use of weaver ants in citrus cultivation in southern China is considered one of the oldest known applications of biological control.[170] On the other hand, ants may become nuisances when they invade buildings, or cause economic losses.
+
+In some parts of the world (mainly Africa and South America), large ants, especially army ants, are used as surgical sutures. The wound is pressed together and ants are applied along it. The ant seizes the edges of the wound in its mandibles and locks in place. The body is then cut off and the head and mandibles remain in place to close the wound.[171][172][173] The large heads of the dinergates (soldiers) of the leafcutting ant Atta cephalotes are also used by native surgeons in closing wounds.[174]
+
+Some ants have toxic venom and are of medical importance. The species include Paraponera clavata (tocandira) and Dinoponera spp. (false tocandiras) of South America [175] and the Myrmecia ants of Australia.[176]
+
+In South Africa, ants are used to help harvest the seeds of rooibos (Aspalathus linearis), a plant used to make a herbal tea. The plant disperses its seeds widely, making manual collection difficult. Black ants collect and store these and other seeds in their nest, where humans can gather them en masse. Up to half a pound (200 g) of seeds may be collected from one ant-heap.[177][178]
+
+Although most ants survive attempts by humans to eradicate them, a few are highly endangered. These tend to be island species that have evolved specialized traits and risk being displaced by introduced ant species. Examples include the critically endangered Sri Lankan relict ant (Aneuretus simoni) and Adetomyrma venatrix of Madagascar.[179]
+
+It has been estimated by E.O. Wilson that the total number of individual ants alive in the world at any one time is between one and ten quadrillion (short scale) (i.e., between 1015 and 1016). According to this estimate, the total biomass of all the ants in the world is approximately equal to the total biomass of the entire human race.[180] Also, according to this estimate, there are approximately 1 million ants for every human on Earth.[181]
+
+Ants and their larvae are eaten in different parts of the world. The eggs of two species of ants are used in Mexican escamoles. They are considered a form of insect caviar and can sell for as much as US$40 per pound ($90/kg) because they are seasonal and hard to find. In the Colombian department of Santander, hormigas culonas (roughly interpreted as "large-bottomed ants") Atta laevigata are toasted alive and eaten.[182]
+
+In areas of India, and throughout Burma and Thailand, a paste of the green weaver ant (Oecophylla smaragdina) is served as a condiment with curry.[183] Weaver ant eggs and larvae, as well as the ants, may be used in a Thai salad, yam (Thai: ยำ), in a dish called yam khai mot daeng (Thai: ยำไข่มดแดง) or red ant egg salad, a dish that comes from the Issan or north-eastern region of Thailand. Saville-Kent, in the Naturalist in Australia wrote "Beauty, in the case of the green ant, is more than skin-deep. Their attractive, almost sweetmeat-like translucency possibly invited the first essays at their consumption by the human species". Mashed up in water, after the manner of lemon squash, "these ants form a pleasant acid drink which is held in high favor by the natives of North Queensland, and is even appreciated by many European palates".[184]
+
+In his First Summer in the Sierra, John Muir notes that the Digger Indians of California ate the tickling, acid gasters of the large jet-black carpenter ants. The Mexican Indians eat the replete workers, or living honey-pots, of the honey ant (Myrmecocystus).[184]
+
+Some ant species are considered as pests, primarily those that occur in human habitations, where their presence is often problematic. For example, the presence of ants would be undesirable in sterile places such as hospitals or kitchens. Some species or genera commonly categorized as pests include the Argentine ant, pavement ant, yellow crazy ant, banded sugar ant, pharaoh ant, red ant, carpenter ant, odorous house ant, red imported fire ant, and European fire ant. Some ants will raid stored food, some will seek water sources, others may damage indoor structures, some may damage agricultural crops directly (or by aiding sucking pests). Some will sting or bite.[185] The adaptive nature of ant colonies make it nearly impossible to eliminate entire colonies and most pest management practices aim to control local populations and tend to be temporary solutions. Ant populations are managed by a combination of approaches that make use of chemical, biological, and physical methods. Chemical methods include the use of insecticidal bait which is gathered by ants as food and brought back to the nest where the poison is inadvertently spread to other colony members through trophallaxis. Management is based on the species and techniques may vary according to the location and circumstance.[185]
+
+Observed by humans since the dawn of history, the behaviour of ants has been documented and the subject of early writings and fables passed from one century to another. Those using scientific methods, myrmecologists, study ants in the laboratory and in their natural conditions. Their complex and variable social structures have made ants ideal model organisms. Ultraviolet vision was first discovered in ants by Sir John Lubbock in 1881.[186] Studies on ants have tested hypotheses in ecology and sociobiology, and have been particularly important in examining the predictions of theories of kin selection and evolutionarily stable strategies.[187] Ant colonies may be studied by rearing or temporarily maintaining them in formicaria, specially constructed glass framed enclosures.[188] Individuals may be tracked for study by marking them with dots of colours.[189]
+
+The successful techniques used by ant colonies have been studied in computer science and robotics to produce distributed and fault-tolerant systems for solving problems, for example Ant colony optimization and Ant robotics. This area of biomimetics has led to studies of ant locomotion, search engines that make use of "foraging trails", fault-tolerant storage, and networking algorithms.[190]
+
+From the late 1950s through the late 1970s, ant farms were popular educational children's toys in the United States. Some later commercial versions use transparent gel instead of soil, allowing greater visibility at the cost of stressing the ants with unnatural light.[191]
+
+Anthropomorphised ants have often been used in fables and children's stories to represent industriousness and cooperative effort. They also are mentioned in religious texts.[192][193] In the Book of Proverbs in the Bible, ants are held up as a good example for humans for their hard work and cooperation.[194] Aesop did the same in his fable The Ant and the Grasshopper. In the Quran, Sulayman is said to have heard and understood an ant warning other ants to return home to avoid being accidentally crushed by Sulayman and his marching army.[Quran 27:18][195] In parts of Africa, ants are considered to be the messengers of the deities. Some Native American mythology, such as the Hopi mythology, considers ants as the very first animals. Ant bites are often said to have curative properties. The sting of some species of Pseudomyrmex is claimed to give fever relief.[196] Ant bites are used in the initiation ceremonies of some Amazon Indian cultures as a test of endurance.[197][198]
+
+Ant society has always fascinated humans and has been written about both humorously and seriously. Mark Twain wrote about ants in his 1880 book A Tramp Abroad.[199] Some modern authors have used the example of the ants to comment on the relationship between society and the individual. Examples are Robert Frost in his poem "Departmental" and T. H. White in his fantasy novel The Once and Future King. The plot in French entomologist and writer Bernard Werber's Les Fourmis science-fiction trilogy is divided between the worlds of ants and humans; ants and their behaviour is described using contemporary scientific knowledge. H.G. Wells wrote about intelligent ants destroying human settlements in Brazil and threatening human civilization in his 1905 science-fiction short story, The Empire of the Ants. In more recent times, animated cartoons and 3-D animated films featuring ants have been produced including Antz, A Bug's Life, The Ant Bully, The Ant and the Aardvark, Ferdy the Ant and Atom Ant. Renowned myrmecologist E. O. Wilson wrote a short story, "Trailhead" in 2010 for The New Yorker magazine, which describes the life and death of an ant-queen and the rise and fall of her colony, from an ants' point of view.[200] The French neuroanatomist, psychiatrist and eugenicist Auguste Forel believed that ant societies were models for human society. He published a five volume work from 1921 to 1923 that examined ant biology and society.[201]
+
+In the early 1990s, the video game SimAnt, which simulated an ant colony, won the 1992 Codie award for "Best Simulation Program".[202]
+
+Ants also are quite popular inspiration for many science-fiction insectoids, such as the Formics of Ender's Game, the Bugs of Starship Troopers, the giant ants in the films Them! and Empire of the Ants, Marvel Comics' super hero Ant-Man, and ants mutated into super-intelligence in Phase IV. In computer strategy games, ant-based species often benefit from increased production rates due to their single-minded focus, such as the Klackons in the Master of Orion series of games or the ChCht in Deadlock II. These characters are often credited with a hive mind, a common misconception about ant colonies.[203]
+

en/2043.html.txt

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+
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+Coordinates: 24°N 121°E / 24°N 121°E / 24; 121
+
+Taiwan,[II] officially the Republic of China,[I] is a country in East Asia.[15][16] Neighbouring countries include the People's Republic of China (PRC) to the northwest, Japan to the northeast, and the Philippines to the south. The main island of Taiwan has an area of 35,808 square kilometres (13,826 sq mi), with mountain ranges dominating the eastern two-thirds and plains in the western third, where its highly urbanised population is concentrated. Taipei is the capital and largest metropolitan area. Other major cities include New Taipei, Kaohsiung, Taichung, Tainan and Taoyuan. With 23.7 million inhabitants, Taiwan is among the most densely populated countries, and is the most populous country and largest economy that is not a member of the United Nations (UN).
+
+Taiwanese indigenous peoples settled the island of Taiwan around 6,000 years ago. In the 17th century, partial Dutch colonization opened the island to mass Han immigration. After the brief Kingdom of Tungning in parts of the southern and western areas of the island, the island was annexed in 1683 by the Qing dynasty of China, and ceded to the Empire of Japan in 1895. Following the surrender of Japan in 1945, the Republic of China, which had overthrown and succeeded the Qing in 1911, took control of Taiwan on behalf of the World War II Allies. The resumption of the Chinese Civil War led to the loss of the mainland to the Communist Party of China and the flight of the ROC government to Taiwan in 1949. Although the ROC government continued to claim to be the legitimate representative of China, since 1950 its effective jurisdiction has been limited to Taiwan and numerous smaller islands. In the early 1960s, Taiwan entered a period of rapid economic growth and industrialisation called the "Taiwan Miracle". In the late 1980s and early 1990s, the ROC transitioned from a one-party military dictatorship to a multi-party democracy with a semi-presidential system.
+
+Taiwan's export-oriented industrial economy is the 21st-largest in the world, with major contributions from steel, machinery, electronics and chemicals manufacturing. Taiwan is a developed country,[17][18] ranking 15th in GDP per capita. It is ranked highly in terms of political and civil liberties,[19] education, health care[20] and human development.[e][24]
+
+The political status of Taiwan remains uncertain. The ROC is no longer a member of the UN, having been replaced by the PRC in 1971. Taiwan is claimed by the PRC, which refuses diplomatic relations with countries that recognise the ROC. Taiwan maintains official ties with 14 out of 193 UN member states and the Holy See.[25][26] International organisations in which the PRC participates either refuse to grant membership to Taiwan or allow it to participate only on a non-state basis. Taiwan is a member of the World Trade Organization, Asia-Pacific Economic Cooperation and Asian Development Bank under various names. Nearby countries and countries with large economies maintain unofficial ties with Taiwan through representative offices and institutions that function as de facto embassies and consulates. Domestically, the major political division is between parties favouring eventual Chinese unification and promoting a Chinese identity contrasted with those aspiring to independence and promoting Taiwanese identity, although both sides have moderated their positions to broaden their appeal.[27][28]
+
+Various names for the island of Taiwan remain in use, each derived from explorers or rulers during a particular historical period. The name Formosa (福爾摩沙) dates from 1542, when Portuguese sailors sighted an uncharted island and noted it on their maps as Ilha Formosa ("beautiful island").[30][31] The name Formosa eventually "replaced all others in European literature"[attribution needed][32] and remained in common use among English speakers into the 20th century.[33]
+
+In the early 17th century, the Dutch East India Company established a commercial post at Fort Zeelandia (modern-day Anping, Tainan) on a coastal sandbar called "Tayouan",[34] after their ethnonym for a nearby Taiwanese aboriginal tribe, possibly Taivoan people, written by the Dutch and Portuguese variously as Taiouwang, Tayowan, Teijoan, etc.[35] This name was also adopted into the Chinese vernacular (in particular, Hokkien, as Pe̍h-ōe-jī: Tāi-oân/Tâi-oân) as the name of the sandbar and nearby area (Tainan). The modern word "Taiwan" is derived from this usage, which is seen in various forms (大員, 大圓, 大灣, 臺員, 臺圓 and 臺窩灣) in Chinese historical records. The area occupied by modern-day Tainan represented the first permanent settlement by both European colonists and Chinese immigrants. The settlement grew to be the island's most important trading centre and served as its capital until 1887.
+
+Use of the current Chinese name (臺灣/台灣) became official as early as 1684 with the establishment of Taiwan Prefecture. Through its rapid development the entire Formosan mainland eventually became known as "Taiwan".[36][37][38][39]
+
+In his Daoyi Zhilüe (1349), Wang Dayuan used "Liuqiu" as a name for the island of Taiwan, or the part of it closest to Penghu.[40]
+Elsewhere, the name was used for the Ryukyu Islands in general or Okinawa, the largest of them; indeed the name Ryūkyū is the Japanese form of Liúqiú. The name also appears in the Book of Sui (636) and other early works, but scholars cannot agree on whether these references are to the Ryukyus, Taiwan or even Luzon.[41]
+
+The official name of the country is the "Republic of China"; it has also been known under various names throughout its existence. Shortly after the ROC's establishment in 1912, while it was still located on the Chinese mainland, the government used the short form "China" (Zhōngguó (中國)) to refer to itself, which derives from zhōng ("central" or "middle") and guó ("state, nation-state"),[f] a term which also developed under the Zhou dynasty in reference to its royal demesne,[g] and the name was then applied to the area around Luoyi (present-day Luoyang) during the Eastern Zhou and then to China's Central Plain before being used as an occasional synonym for the state during the Qing era.[43]
+
+During the 1950s and 1960s, after the government had withdrawn to Taiwan upon losing the Chinese Civil War, it was commonly referred to as "Nationalist China" (or "Free China") to differentiate it from "Communist China" (or "Red China").[45]
+
+It was a member of the United Nations representing "China" until 1971, when it lost its seat to the People's Republic of China. Over subsequent decades, the Republic of China has become commonly known as "Taiwan", after the island that comprises 99% of the territory under its control. In some contexts, especially ROC government publications, the name was written as "Republic of China/Taiwan", or sometimes "Taiwan (ROC)"[46][47][48]
+
+The Republic of China participates in most international forums and organizations under the name "Chinese Taipei" due to diplomatic pressure from the People's Republic of China. For instance, it is the name under which it has competed at the Olympic Games since 1984, and its name as an observer at the World Health Organization.[49]
+
+Taiwan was joined to the mainland in the Late Pleistocene, until sea levels rose about 10,000 years ago. Fragmentary human remains dated 20,000 to 30,000 years ago have been found on the island, as well as later artifacts of a paleolithic culture.[50][51][52]
+
+Around 6,000 years ago, Taiwan was settled by farmers, most likely from mainland China.[53] 
+They are believed to be the ancestors of today's Taiwanese indigenous peoples, whose languages belong to the Austronesian language family, but show much greater diversity than the rest of the family, which spans a huge area from Maritime Southeast Asia west to Madagascar and east as far as New Zealand, Hawaii and Easter Island. This has led linguists to propose Taiwan as the urheimat of the family, from which seafaring peoples dispersed across Southeast Asia and the Pacific and Indian Oceans.[54][55]
+
+Han Chinese fishermen began settling in the Penghu islands in the 13th century.[56] Hostile tribes, and a lack of valuable trade products, meant that few outsiders visited the main island until the 16th century.[56] During the 16th century, visits to the coast by fishermen and traders from Fujian, as well as Chinese and Japanese pirates, became more frequent.[56] The Kingdom of Middag that existed from before the Portuguese and Spanish colonial period was a supra-tribal alliance located in the central western plains of Taiwan that was brutally conquered by Qing troops and collaborative indigenous communities in 1732.
+
+The Dutch East India Company attempted to establish a trading outpost on the Penghu Islands (Pescadores) in 1622, but were driven off by Ming forces.[57]
+In 1624, the company established a stronghold called Fort Zeelandia on the coastal islet of Tayouan, which is now part of the main island at Anping, Tainan.[39]
+When the Dutch arrived, they found southwestern Taiwan already frequented by a mostly-transient Chinese population numbering close to 1,500.[58]
+David Wright, a Scottish agent of the company who lived on the island in the 1650s, described the lowland areas of the island as being divided among 11 chiefdoms ranging in size from two settlements to 72. Some of these fell under Dutch control, while others remained independent.[39][59] The Company began to import labourers from Fujian and Penghu, many of whom settled.[57]
+
+In 1626, the Spanish Empire landed on and occupied northern Taiwan, at the ports of Keelung and Tamsui, as a base to extend their trading. This colony lasted 16 years until 1642, when the last Spanish fortress fell to Dutch forces.
+
+Following the fall of the Ming dynasty, Koxinga (Zheng Chenggong), a self-styled Ming loyalist, arrived on the island and captured Fort Zeelandia in 1662, expelling the Dutch Empire and military from the island. Koxinga established the Kingdom of Tungning (1662–1683), with his capital at Tainan. He and his heirs, Zheng Jing, who ruled from 1662 to 1682, and Zheng Keshuang, who ruled less than a year, continued to launch raids on the southeast coast of mainland China well into the Qing dynasty era.[57]
+
+In 1683, following the defeat of Koxinga's grandson by an armada led by Admiral Shi Lang of southern Fujian, the Qing dynasty formally annexed Taiwan, placing it under the jurisdiction of Fujian province. The Qing imperial government tried to reduce piracy and vagrancy in the area, issuing a series of edicts to manage immigration and respect aboriginal land rights. Immigrants mostly from southern Fujian continued to enter Taiwan. The border between taxpaying lands and what was considered "savage" lands shifted eastward, with some aborigines becoming sinicized while others retreated into the mountains. During this time, there were a number of conflicts between different ethnic groups of Han Chinese, Quanzhou Minnanese feuding with Zhangzhou and Hakkas peasants, and major clan fights between Minnans (Hoklos), Hakkas and aborigines too.
+
+There were more than a hundred rebellions during the early Qing including the Lin Shuangwen rebellion (1786-1788). The frequency of rebellions, riots, and civil strife in Qing Taiwan is evoked by the common saying "every three years an uprising; every five years a rebellion" (三年一反、五年一亂).[60][61]
+
+Northern Taiwan and the Penghu Islands were the scene of subsidiary campaigns in the Sino-French War (August 1884 to April 1885). The French occupied Keelung on 1 October 1884, but were repulsed from Tamsui a few days later. The French won some tactical victories but were unable to exploit them, and the Keelung Campaign ended in stalemate. The Pescadores Campaign, beginning on 31 March 1885, was a French victory, but had no long-term consequences. The French evacuated both Keelung and the Penghu archipelago after the end of the war.
+
+In 1887, the Qing upgraded the island's administration from being the Taiwan Prefecture of Fujian Province to Fujian-Taiwan-Province, the twentieth in the empire, with its capital at Taipei. This was accompanied by a modernization drive that included building China's first railway.[62]
+
+As the Qing dynasty was defeated in the First Sino-Japanese War (1894–1895), Taiwan, along with Penghu and Liaodong Peninsula, were ceded in full sovereignty to the Empire of Japan by the Treaty of Shimonoseki. Inhabitants on Taiwan and Penghu wishing to remain Qing subjects were given a two-year grace period to sell their property and move to mainland China. Very few Taiwanese saw this as feasible.[63] On 25 May 1895, a group of pro-Qing high officials proclaimed the Republic of Formosa to resist impending Japanese rule. Japanese forces entered the capital at Tainan and quelled this resistance on 21 October 1895.[64] Guerrilla fighting continued periodically until about 1902 and ultimately took the lives of 14,000 Taiwanese, or 0.5% of the population.[65] Several subsequent rebellions against the Japanese (the Beipu uprising of 1907, the Tapani incident of 1915, and the Musha incident of 1930) were all unsuccessful but demonstrated opposition to Japanese colonial rule.
+
+Japanese colonial rule was instrumental in the industrialization of the island, extending the railways and other transport networks, building an extensive sanitation system, and establishing a formal education system in Taiwan.[66] Japanese rule ended the practice of headhunting.[67] During this period the human and natural resources of Taiwan were used to aid the development of Japan and the production of cash crops such as rice and sugar greatly increased. By 1939, Taiwan was the seventh-greatest sugar producer in the world.[68] Still, the Taiwanese and aborigines were classified as second- and third-class citizens. After suppressing Chinese guerrillas in the first decade of their rule, Japanese authorities engaged in a series of bloody campaigns against the mountain aboriginals, culminating in the Musha Incident of 1930.[69] Intellectuals and labourers who participated in left-wing movements within Taiwan were also arrested and massacred (e.g. Chiang Wei-shui (蔣渭水) and Masanosuke Watanabe (渡辺政之輔)).[70]
+
+Around 1935, the Japanese began an island-wide assimilation project to bind the island more firmly to the Japanese Empire and people were taught to see themselves as Japanese under the Kominka Movement, during which time Taiwanese culture and religion were outlawed and the citizens were encouraged to adopt Japanese surnames.[71] By 1938, 309,000 Japanese settlers resided in Taiwan.[72]
+
+Taiwan held strategic wartime importance as Imperial Japanese military campaigns first expanded and then contracted over the course of World War II. The "South Strike Group" was based at the Taihoku Imperial University in Taipei. During World War II, tens of thousands of Taiwanese served in the Japanese military.[73] Over 2,000 women, euphemistically called "comfort women", were forced into sexual slavery for Imperial Japanese troops.[74]
+
+The Imperial Japanese Navy operated heavily out of Taiwanese ports. In October 1944 the Formosa Air Battle was fought between American carriers and Japanese forces based in Taiwan. Important Japanese military bases and industrial centres throughout Taiwan, such as Kaohsiung and Keelung, were targets of heavy raids by American bombers.[75]
+
+After Japan's surrender ended World War II, most of Taiwan's approximately 300,000 Japanese residents were expelled and sent to Japan.[76]
+
+While Taiwan was still under Japanese rule, the Republic of China was founded on the mainland on 1 January 1912, following the Xinhai Revolution, which began with the Wuchang uprising on 10 October 1911, replacing the Qing dynasty and ending over two thousand years of imperial rule in China.[77] From its founding until 1949 it was based in mainland China. Central authority waxed and waned in response to warlordism (1915–28), Japanese invasion (1937–45), and the Chinese Civil War (1927–50), with central authority strongest during the Nanjing decade (1927–37), when most of China came under the control of the Kuomintang (KMT) under an authoritarian one-party state.[78]
+
+After the Surrender of Japan on 25 October 1945, the US Navy ferried ROC troops to Taiwan to accept the formal surrender of Japanese military forces in Taipei on behalf of the Allied Powers, as part of General Order No. 1 for temporary military occupation. General Rikichi Andō, governor-general of Taiwan and commander-in-chief of all Japanese forces on the island, signed the receipt and handed it over to General Chen Yi of the ROC military to complete the official turnover. Chen Yi proclaimed that day to be "Taiwan Retrocession Day", but the Allies considered Taiwan and the Penghu Islands to be under military occupation and still under Japanese sovereignty until 1952, when the Treaty of San Francisco took effect.[79][80]
+Although the 1943 Cairo Declaration had envisaged returning these territories to China, it had no legal status as treaty, and also in the Treaty of San Francisco and Treaty of Taipei Japan renounced all claim to them without specifying to what country they were to be surrendered. This introduced the disputed sovereignty status of Taiwan and whether the ROC has sovereignty over Taiwan or only remaining over Kinmen and Matsu Islands.
+
+The ROC administration of Taiwan under Chen Yi was strained by increasing tensions between Taiwanese-born people and newly arrived mainlanders, which were compounded by economic woes, such as hyperinflation. Furthermore, cultural and linguistic conflicts between the two groups quickly led to the loss of popular support for the new government, while the mass movement led by the working committee of the Communist Party also aimed to bring down the Kuomintang government.[81][82] The shooting of a civilian on 28 February 1947 triggered island-wide unrest, which was suppressed with military force in what is now called the February 28 Incident. Mainstream estimates of the number killed range from 18,000 to 30,000. Those killed were mainly members of the Taiwanese elite.[83][84]
+
+After the end of World War II, the Chinese Civil War resumed between the Chinese Nationalists (Kuomintang), led by Chiang Kai-shek, and the Communist Party of China, led by Mao Zedong. Throughout the months of 1949, a series of Chinese Communist offensives led to the capture of its capital Nanjing on 23 April and the subsequent defeat of the Nationalist army on the mainland, and the Communists founded the People's Republic of China on 1 October.[85]
+
+On 7 December 1949, after the loss of four capitals, Chiang evacuated his Nationalist government to Taiwan and made Taipei the temporary capital of the ROC (also called the "wartime capital" by Chiang Kai-shek).[86] Some 2 million people, consisting mainly of soldiers, members of the ruling Kuomintang and intellectual and business elites, were evacuated from mainland China to Taiwan at that time, adding to the earlier population of approximately six million. In addition, the ROC government took to Taipei many national treasures and much of China's gold reserves and foreign currency reserves.[87][88][89]
+
+After losing most of the mainland, the Kuomintang remained in control of Tibet, portions of Qinghai, Xinjiang, and Yunnan along with Hainan Island until 1951 when the Communists subsequently captured these territories too. From this point onwards, the Kuomintang's territory was reduced to the island of Taiwan, Penghu, Kinmen and Matsu Islands (Fujian Province), and two major islands of the Dongsha and Nansha island groups. The Kuomintang continued to claim sovereignty over all of "China", which it defined to include mainland China, Taiwan, Outer Mongolia and other areas. On mainland China, the victorious Communists claimed they ruled the sole and only China (which they claimed included Taiwan) and that the Republic of China no longer existed.[90]
+
+Martial law, declared on Taiwan in May 1949,[91] continued to be in effect after the central government relocated to Taiwan. It was not repealed until 38 years later, in 1987.[91] Martial law was used as a way to suppress the political opposition during the years it was active.[92] During the White Terror, as the period is known, 140,000 people were imprisoned or executed for being perceived as anti-KMT or pro-Communist.[93] Many citizens were arrested, tortured, imprisoned and executed for their real or perceived link to the Communists. Since these people were mainly from the intellectual and social elite, an entire generation of political and social leaders was decimated. In 1998, a law was passed to create the "Compensation Foundation for Improper Verdicts" which oversaw compensation to White Terror victims and families. President Ma Ying-jeou made an official apology in 2008, expressing hope that there would never be a tragedy similar to White Terror.[94]
+
+Initially, the United States abandoned the KMT and expected that Taiwan would fall to the Communists. However, in 1950 the conflict between North Korea and South Korea, which had been ongoing since the Japanese withdrawal in 1945, escalated into full-blown war, and in the context of the Cold War, US President Harry S. Truman intervened again and dispatched the US Navy's 7th Fleet into the Taiwan Strait to prevent hostilities between Taiwan and mainland China.[95] In the Treaty of San Francisco and the Treaty of Taipei, which came into force respectively on 28 April 1952 and 5 August 1952, Japan formally renounced all right, claim and title to Taiwan and Penghu, and renounced all treaties signed with China before 1942. Neither treaty specified to whom sovereignty over the islands should be transferred, because the United States and the United Kingdom disagreed on whether the ROC or the PRC was the legitimate government of China.[96] Continuing conflict of the Chinese Civil War through the 1950s, and intervention by the United States notably resulted in legislation such as the Sino-American Mutual Defense Treaty and the Formosa Resolution of 1955.
+
+As the Chinese Civil War continued without truce, the government built up military fortifications throughout Taiwan. Within this effort, KMT veterans built the now famous Central Cross-Island Highway through the Taroko Gorge in the 1950s. The two sides would continue to engage in sporadic military clashes with seldom publicized details well into the 1960s on the China coastal islands with an unknown number of night raids. During the Second Taiwan Strait Crisis in September 1958, Taiwan's landscape saw Nike-Hercules missile batteries added, with the formation of the 1st Missile Battalion Chinese Army that would not be deactivated until 1997. Newer generations of missile batteries have since replaced the Nike Hercules systems throughout the island.
+
+During the 1960s and 1970s, the ROC maintained an authoritarian, single-party government while its economy became industrialized and technology-oriented. This rapid economic growth, known as the Taiwan Miracle, was the result of a fiscal regime independent from mainland China and backed up, among others, by the support of US funds and demand for Taiwanese products.[97][98] In the 1970s, Taiwan was economically the second fastest growing state in Asia after Japan.[99] Taiwan, along with Hong Kong, South Korea and Singapore, became known as one of the Four Asian Tigers. Because of the Cold War, most Western nations and the United Nations regarded the ROC as the sole legitimate government of China until the 1970s. Later, especially after the termination of the Sino-American Mutual Defense Treaty, most nations switched diplomatic recognition to the PRC (see United Nations General Assembly Resolution 2758).
+
+Until the 1970s the government was regarded by Western critics as undemocratic for upholding martial law, for severely repressing any political opposition, and for controlling media. The KMT did not allow the creation of new parties and those that existed did not seriously compete with the KMT. Thus, competitive democratic elections did not exist.[100][101][102][103][104] From the late 1970s to the 1990s, however, Taiwan went through reforms and social changes that transformed it from an authoritarian state to a democracy. In 1979, a pro-democracy protest known as the Kaohsiung Incident took place in Kaohsiung to celebrate Human Rights Day. Although the protest was rapidly crushed by the authorities, it is today considered as the main event that united Taiwan's opposition.[105]
+
+Chiang Ching-kuo, Chiang Kai-shek's son and successor as the president, began reforms to the political system in the mid-1980s. In 1984, the younger Chiang selected Lee Teng-hui, a Taiwanese-born, US-educated technocrat, to be his vice-president. In 1986, the Democratic Progressive Party (DPP) was formed and inaugurated as the first opposition party in the ROC to counter the KMT. A year later, Chiang Ching-kuo lifted martial law on the main island of Taiwan (martial law was lifted on Penghu in 1979, Matsu island in 1992 and Kinmen island in 1993). With the advent of democratization, the issue of the political status of Taiwan gradually resurfaced as a controversial issue where, previously, the discussion of anything other than unification under the ROC was taboo.
+
+After the death of Chiang Ching-kuo in January 1988, Lee Teng-hui succeeded him and became the first president born in Taiwan. Lee continued the democratic reforms to the government and decreased the concentration of government authority in the hands of mainland Chinese. Under Lee, Taiwan underwent a process of localization in which Taiwanese culture and history were promoted over a pan-China viewpoint in contrast to earlier KMT policies which had promoted a Chinese identity. Lee's reforms included printing banknotes from the Central Bank rather than the Provincial Bank of Taiwan, and streamlining the Taiwan Provincial Government with most of its functions transferred to the Executive Yuan. Under Lee, the original members of the Legislative Yuan and National Assembly (a former supreme legislative body defunct in 2005),[106] elected in 1947 to represent mainland Chinese constituencies and having held the seats without re-election for more than four decades, were forced to resign in 1991. The previously nominal representation in the Legislative Yuan was brought to an end, reflecting the reality that the ROC had no jurisdiction over mainland China, and vice versa. Restrictions on the use of Taiwanese Hokkien in the broadcast media and in schools were also lifted.[107]
+
+Reforms continued in the 1990s. The Additional Articles of the Constitution of the Republic of China and the Act Governing Relations between the People of the Taiwan Area and the Mainland Area defined the status of the ROC, making Taiwan its de facto territory. Lee Teng-hui re-elected in 1996, in the first direct presidential election in the history of the ROC.[108] During the later years of Lee's administration, he was involved in corruption controversies relating to government release of land and weapons purchase, although no legal proceedings commenced. In 1997,"To meet the requisites of the nation prior to national unification",[109] the Additional Articles of the Constitution of the Republic of China was passed and then the former "constitution of five powers" turns to be more tripartite. In 2000, Chen Shui-bian of the Democratic Progressive Party was elected as the first non-Kuomintang (KMT) President and was re-elected to serve his second and last term since 2004. Polarized politics emerged in Taiwan with the formation of the Pan-Blue Coalition, led by the KMT, and the Pan-Green Coalition, led by the DPP. The former favors eventual Chinese unification, while the latter favors Taiwanese independence.[110] In early 2006, President Chen Shui-bian remarked:
+"The National Unification Council will cease to function. No budget will be ear-marked for it and its personnel must return to their original posts...The National Unification Guidelines will cease to apply."[111]
+
+On 30 September 2007, the ruling DPP approved a resolution asserting a separate identity from China and called for the enactment of a new constitution for a "normal country". It also called for general use of "Taiwan" as the country's name, without abolishing its formal name, the Republic of China.[112] The Chen administration also pushed for referendums on cross-Strait relations in 2004 and UN entry in 2008, both of which held on the same day as the presidential election. They both failed due to voter turnout below the required legal threshold of 50% of all registered voters.[113] The Chen administration was dogged by public concerns over reduced economic growth, legislative gridlock due to a pan-blue, opposition-controlled Legislative Yuan and corruption involving the First Family as well as government officials.[114][115]
+
+The KMT increased its majority in the Legislative Yuan in the January 2008 legislative elections, while its nominee Ma Ying-jeou went on to win the presidency in March of the same year, campaigning on a platform of increased economic growth and better ties with the PRC under a policy of "mutual nondenial".[113] Ma took office on 20 May 2008, the same day that President Chen Shui-bian stepped down and was notified by prosecutors of possible corruption charges. Part of the rationale for campaigning for closer economic ties with the PRC stems from the strong economic growth China attained since joining the World Trade Organization. However, some analysts said that despite the election of Ma Ying-jeou, the diplomatic and military tensions with the PRC had not been reduced.[116]
+
+In 2016, Tsai Ing-wen of the Democratic Progressive Party (DPP) became President of Taiwan. President Tsai requested the international community to help Taiwan preserve its de facto independence despite the objections raised by Xi Jinping, General Secretary of the Communist Party of China (PRC paramount leader).[117] President Tsai called upon the PRC to democratize, respect human rights, and renounce the use of military force against Taiwan.[118] She was re-elected in 2020.
+
+Taiwan is an island country in East Asia. The main island, known historically as Formosa, makes up 99% of the area controlled by the ROC, measuring 35,808 square kilometres (13,826 sq mi) and lying some 180 kilometres (112 mi) across the Taiwan Strait from the southeastern coast of mainland China. The East China Sea lies to its north, the Philippine Sea to its east, the Luzon Strait directly to its south and the South China Sea to its southwest. Smaller islands include a number in the Taiwan Strait including the Penghu archipelago, the Kinmen and Matsu Islands near the Chinese coast, and some of the South China Sea Islands.
+
+The main island is a tilted fault block, characterized by the contrast between the eastern two-thirds, consisting mostly of five rugged mountain ranges parallel to the east coast, and the flat to gently rolling plains of the western third, where the majority of Taiwan's population reside. There are several peaks over 3,500 m, the highest being Yu Shan at 3,952 m (12,966 ft), making Taiwan the world's fourth-highest island. The tectonic boundary that formed these ranges is still active, and the island experiences many earthquakes, a few of them highly destructive. There are also many active submarine volcanoes in the Taiwan Straits.
+
+The eastern mountains are heavily forested and home to a diverse range of wildlife, while land use in the western and northern lowlands is intensive.
+
+Taiwan lies on the Tropic of Cancer, and its general climate is marine tropical.[7] The northern and central regions are subtropical, whereas the south is tropical and the mountainous regions are temperate.[119] The average rainfall is 2,600 millimetres (100 inches) per year for the island proper; the rainy season is concurrent with the onset of the summer East Asian Monsoon in May and June.[120] The entire island experiences hot, humid weather from June through September. Typhoons are most common in July, August and September.[120] During the winter (November to March), the northeast experiences steady rain, while the central and southern parts of the island are mostly sunny.
+
+The island of Taiwan lies in a complex tectonic area between the Yangtze Plate to the west and north, the Okinawa Plate on the north-east, and the Philippine Mobile Belt on the east and south. The upper part of the crust on the island is primarily made up of a series of terranes, mostly old island arcs which have been forced together by the collision of the forerunners of the Eurasian Plate and the Philippine Sea Plate. These have been further uplifted as a result of the detachment of a portion of the Eurasian Plate as it was subducted beneath remnants of the Philippine Sea Plate, a process which left the crust under Taiwan more buoyant.[121]
+
+The east and south of Taiwan are a complex system of belts formed by, and part of the zone of, active collision between the North Luzon Trough portion of the Luzon Volcanic Arc and South China, where accreted portions of the Luzon Arc and Luzon forearc form the eastern Coastal Range and parallel inland Longitudinal Valley of Taiwan respectively.[122]
+
+The major seismic faults in Taiwan correspond to the various suture zones between the various terranes. These have produced major quakes throughout the history of the island. On 21 September 1999, a 7.3 quake known as the "921 earthquake" killed more than 2,400 people. The seismic hazard map for Taiwan by the USGS shows 9/10 of the island at the highest rating (most hazardous).[123]
+
+The political and legal statuses of Taiwan are contentious issues. The People's Republic of China (PRC) claims that the Republic of China government is illegitimate, referring to it as the "Taiwan Authority".[124][125] The ROC has its own currency, widely accepted passport, postage stamps, internet TLD, armed forces and constitution with an independently elected president. It has not formally renounced its claim to the mainland, but ROC government publications have increasingly downplayed this historical claim.[126]
+
+Internationally, there is controversy on whether the ROC still exists as a state or a defunct state per international law due to the lack of wide diplomatic recognition. In a poll of Taiwanese aged 20 and older taken by TVBS in March 2009, a majority of 64% opted for the "status quo", while 19% favoured "independence" and 5% favoured "unification".[127]
+
+The political environment is complicated by the potential for military conflict should Taiwan declare de jure independence. It is the official PRC policy to force unification if peaceful unification is no longer possible, as stated in its anti-secession law, and for this reason there is a substantial military presence on the Fujian coast.[128][129][130][131][132]
+
+On 29 April 2005, Kuomintang Chairman Lien Chan travelled to Beijing and met with Communist Party of China (CPC) General Secretary Hu Jintao,[133] the first meeting between the leaders of the two parties since the end of the Chinese Civil War in 1949. On 11 February 2014, Mainland Affairs Council head Wang Yu-chi travelled to Nanjing and met with Taiwan Affairs Office head Zhang Zhijun, the first meeting between high-ranking officials from either side.[134] Zhang paid a reciprocal visit to Taiwan and met Wang on 25 June 2014, making Zhang the first minister-level PRC official to ever visit Taiwan.[135] On 7 November 2015, Ma Ying-jeou (in his capacity as Leader of Taiwan) and Xi Jinping (in his capacity as leader of Mainland China[136]) travelled to Singapore and met up,[137] marking the highest-level exchange between the two sides since 1945.[138] In response to US support for Taiwan, the PRC defence ministry declared in 2019 that "If anyone dares to split Taiwan from China, the Chinese military has no choice but to fight at all costs".[139]
+
+The PRC supports a version of the One-China policy, which states that Taiwan and mainland China are both part of China, and that the PRC is the only legitimate government of China. It uses this policy to prevent the international recognition of the ROC as an independent sovereign state, meaning that Taiwan participates in international forums under the name "Chinese Taipei". With the emergence of the Taiwanese independence movement, the name "Taiwan" has been used increasingly often on the island.[140]
+
+President Tsai Ing-wen has supported the 2019–20 Hong Kong protests and expressed her solidarity with the people of Hong Kong. Pledging that as long as she is Taiwan's president, Tsai will never accept "one country, two systems".[141]
+
+Before 1928, the foreign policy of Republican China was complicated by a lack of internal unity—competing centres of power all claimed legitimacy. This situation changed after the defeat of the Peiyang Government by the Kuomintang, which led to widespread diplomatic recognition of the Republic of China.[142]
+
+After the KMT's retreat to Taiwan, most countries, notably the countries in the Western Bloc, continued to maintain relations with the ROC. Due to diplomatic pressure, recognition gradually eroded and many countries switched recognition to the PRC in the 1970s. UN Resolution 2758 (25 October 1971) recognized the People's Republic of China as China's sole representative in the United Nations.[143]
+
+The PRC refuses to have diplomatic relations with any nation that has diplomatic relations with the ROC, and requires all nations with which it has diplomatic relations to make a statement recognizing its claims to Taiwan.[144] As a result, only 14 UN member states and the Holy See maintain official diplomatic relations with the Republic of China.[25] The ROC maintains unofficial relations with most countries via de facto embassies and consulates called Taipei Economic and Cultural Representative Offices (TECRO), with branch offices called "Taipei Economic and Cultural Offices" (TECO). Both TECRO and TECO are "unofficial commercial entities" of the ROC in charge of maintaining diplomatic relations, providing consular services (i.e. visa applications), and serving the national interests of the ROC in other countries.[145]
+
+The United States remains one of the main allies of Taiwan and, through the Taiwan Relations Act passed in 1979, has continued selling arms and providing military training to the Armed Forces.[146] This situation continues to be an issue for the People's Republic of China, which considers US involvement disruptive to the stability of the region. In January 2010, the Obama administration announced its intention to sell $6.4 billion worth of military hardware to Taiwan. As a consequence, the PRC threatened the US with economic sanctions and warned that their co-operation on international and regional issues could suffer.[147]
+
+The official position of the United States is that the PRC is expected to "use no force or threat[en] to use force against Taiwan" and the ROC is to "exercise prudence in managing all aspects of Cross-Strait relations." Both are to refrain from performing actions or espousing statements "that would unilaterally alter Taiwan's status".[148]
+
+On 16 December 2015, the Obama administration announced a deal to sell $1.83 billion worth of arms to the armed forces of the ROC.[149][150] The foreign ministry of the PRC had expressed its disapproval for the sales and issued the US a "stern warning", saying it would hurt PRC–US relations.[151]
+
+The ROC was a founding member of the United Nations, and held the seat of China on the Security Council and other UN bodies until 1971, when it was expelled by Resolution 2758 and replaced in all UN organs with the PRC. Each year since 1992, the ROC has petitioned the UN for entry, but its applications have not made it past committee stage.[152]
+
+Due to its limited international recognition, the Republic of China has been a member of the Unrepresented Nations and Peoples Organization (UNPO) since the foundation of the organization in 1991, represented by a government-funded organization, the Taiwan Foundation for Democracy (TFD), under the name "Taiwan".[153][154]
+
+Also due to its One China policy, the PRC only participates in international organizations where the ROC does not participate as a sovereign country. Most member states, including the United States, do not wish to discuss the issue of the ROC's political status for fear of souring diplomatic ties with the PRC.[155] However, both the US and Japan publicly support the ROC's bid for membership in the World Health Organization (WHO) as an observer.[156] However, though the ROC sought to participate in the WHO since 1997,[157][158] their efforts were blocked by the PRC until 2010, when they were invited as observers to attend the World Health Assembly, under the name "Chinese Taipei".[159] In 2017 Taiwan again began to be excluded from the WHO even in an observer capacity.[160] This exclusion caused a number of scandals during the COVID-19 outbreak.[161][162]
+
+Due to PRC pressure, the ROC is forced to use the name "Chinese Taipei" in international events, such as the Olympic Games, where the PRC is also a party.[163] The ROC is typically barred from using its national anthem and national flag in international events due to PRC pressure; ROC spectators attending events such as the Olympics are often barred from bringing ROC flags into venues.[164] Taiwan also participates in the Asia-Pacific Economic Cooperation forum (since 1991) and the World Trade Organization (since 2002) under the name "Chinese Taipei". The ROC is able to participate as "China" in organizations in which the PRC does not participate, such as the World Organization of the Scout Movement.
+
+Within Taiwan, opinions are polarized between those supporting unification, represented by the Pan-Blue Coalition of parties, and those supporting independence, represented by the Pan-Green Coalition.
+
+The KMT, the largest Pan-Blue party, supports the status quo for the indefinite future with a stated ultimate goal of unification. However, it does not support unification in the short term with the PRC as such a prospect would be unacceptable to most of its members and the public.[165] Ma Ying-jeou, chairman of the KMT and former president of the ROC, has set out democracy, economic development to a level near that of Taiwan, and equitable wealth distribution as the conditions that the PRC must fulfill for reunification to occur.[166]
+
+The Democratic Progressive Party, the largest Pan-Green party, officially seeks independence, but in practice also supports the status quo because its members and the public would not accept the risk of provoking the PRC.[167][168]
+
+On 2 September 2008, Mexican newspaper El Sol de México asked President Ma about his views on the subject of "two Chinas" and if there was a solution for the sovereignty issues between the two. The president replied that the relations are neither between two Chinas nor two states. It is a special relationship. Further, he stated that the sovereignty issues between the two cannot be resolved at present, but he quoted the "1992 Consensus", currently[when?] accepted by both the Kuomintang and the Communist Party of China, as a temporary measure until a solution becomes available.[169]
+
+On 27 September 2017, Taiwanese premier William Lai said that he was a "political worker who advocates Taiwan independence", but that as Taiwan was an independent country called the Republic of China, it had no need to declare independence.[170]
+The relationship with the PRC and the related issues of Taiwanese independence and Chinese unification continue to dominate politics.[171]
+
+The government of the Republic of China was founded on the Constitution of the ROC and its Three Principles of the People, which states that the ROC "shall be a democratic republic of the people, to be governed by the people and for the people".[172] The government is divided into five branches (Yuan): the Executive Yuan (cabinet), the Legislative Yuan (Congress or Parliament), the Judicial Yuan, the Control Yuan (audit agency), and the Examination Yuan (civil service examination agency). The constitution was drafted while the ROC still governed the Chinese mainland. It was created by the KMT for the purpose of all of its claimed territory, including Taiwan, even though the Communist Party boycotted the drafting of the constitution. The constitution went into effect on 25 December 1947.[173] The ROC remained under martial law from 1948 until 1987 and much of the constitution was not in effect. Political reforms beginning in the late 1970s and continuing through the early 1990s transformed into a multiparty democracy. Since the lifting of martial law, the Republic of China has democratized and reformed, suspending constitutional components that were originally meant for the whole of China. This process of amendment continues. In 2000, the Democratic Progressive Party (DPP) won the presidency, ending KMT's continuous control of the government. In May 2005, a new National Assembly was elected to reduce the number of parliamentary seats and implement several constitutional reforms. These reforms have been passed; the National Assembly has essentially voted to abolish itself and transfer the power of constitutional reform to the popular ballot.[174]
+
+The head of state and commander-in-chief of the armed forces is the president, who is elected by popular vote for a maximum of 2 four-year terms on the same ticket as the vice-president. The president has authority over the Yuan. The president appoints the members of the Executive Yuan as his cabinet, including a premier, who is officially the President of the Executive Yuan; members are responsible for policy and administration.[172]
+
+The main legislative body is the unicameral Legislative Yuan with 113 seats. Seventy-three are elected by popular vote from single-member constituencies; thirty-four are elected based on the proportion of nationwide votes received by participating political parties in a separate party list ballot; and six are elected from two three-member aboriginal constituencies. Members serve four-year terms. Originally the unicameral National Assembly, as a standing constitutional convention and electoral college, held some parliamentary functions, but the National Assembly was abolished in 2005 with the power of constitutional amendments handed over to the Legislative Yuan and all eligible voters of the Republic via referendums.[172]
+
+The premier is selected by the president without the need for approval from the legislature, but the legislature can pass laws without regard for the president, as neither he nor the Premier wields veto power.[172] Thus, there is little incentive for the president and the legislature to negotiate on legislation if they are of opposing parties. After the election of the pan-Green's Chen Shui-bian as President in 2000, legislation repeatedly stalled because of deadlock with the Legislative Yuan, which was controlled by a pan-Blue majority.[175] Historically, the ROC has been dominated by strongman single party politics. This legacy has resulted in executive powers currently being concentrated in the office of the president rather than the premier, even though the constitution does not explicitly state the extent of the president's executive power.[176]
+
+The Judicial Yuan is the highest judicial organ. It interprets the constitution and other laws and decrees, judges administrative suits, and disciplines public functionaries. The president and vice-president of the Judicial Yuan and additional thirteen justices form the Council of Grand Justices.[177] They are nominated and appointed by the president, with the consent of the Legislative Yuan. The highest court, the Supreme Court, consists of a number of civil and criminal divisions, each of which is formed by a presiding judge and four associate judges, all appointed for life. In 1993, a separate constitutional court was established to resolve constitutional disputes, regulate the activities of political parties and accelerate the democratization process. There is no trial by jury but the right to a fair public trial is protected by law and respected in practice; many cases are presided over by multiple judges.[172]
+
+Capital punishment is still used in Taiwan, although efforts have been made by the government to reduce the number of executions.[178] Between 2005 and 2009, capital punishment was stopped.[179] Nevertheless, according to a survey in 2006, about 80% of Taiwanese still wanted to keep the death penalty.[178]
+
+The Control Yuan is a watchdog agency that monitors (controls) the actions of the executive. It can be considered a standing commission for administrative inquiry and can be compared to the Court of Auditors of the European Union or the Government Accountability Office of the United States.[172]
+
+The Examination Yuan is in charge of validating the qualification of civil servants. It is based on the old imperial examination system used in dynastic China. It can be compared to the European Personnel Selection Office of the European Union or the Office of Personnel Management of the United States.[172]
+
+The tension between mainland China and Taiwan shades most of political life since it is the official policy of the PRC to meet any Taiwanese government move towards "Taiwan independence" with a threat of invasion.[180][117] The PRC's official policy is to reunify Taiwan and mainland China under the formula of "one country, two systems" and refuses to renounce the use of military force, especially should Taiwan seek a declaration of independence.[181]
+
+The political scene is generally divided into two major camps in terms of views on how Taiwan should relate to China or the PRC, referred to as cross-Strait relations. It is the main political difference between two camps: the Pan-Blue Coalition, composed of the pro-unification Kuomintang, People First Party (PFP), and New Party, who believe that the ROC is the sole legitimate government of "China" (including Taiwan) and supports eventual Chinese reunification. The opposition Pan-Green Coalition is composed of the pro-independence DPP and Taiwan Solidarity Union (TSU). It regards Taiwan as an independent, sovereign state synonymous with the ROC, opposes the definition that Taiwan is part of "China", and seeks wide diplomatic recognition and an eventual declaration of formal Taiwan independence.[182] The Pan-Green camp tends to favour emphasizing the Republic of China as being a distinct country from the People's Republic of China. Thus, in September 2007, the then ruling Democratic Progressive Party approved a resolution asserting separate identity from China and called for the enactment of a new constitution for a "normal country". It called also for general use of "Taiwan" as the country's name, without abolishing its formal name, the "Republic of China".[183] Some members of the coalition, such as former President Chen Shui-bian, argue that it is unnecessary to proclaim independence because "Taiwan is already an independent, sovereign country" and the Republic of China is the same as Taiwan.[184] Despite being a member of KMT prior to and during his presidency, Lee Teng-hui also held a similar view and was a supporter of the Taiwanization movement.[185]
+
+Pan-Blue members generally support the concept of the One-China policy, which states that there is only one China and that its only government is the ROC. They favour eventual re-unification of China.[186] The more mainstream Pan-Blue position is to lift investment restrictions and pursue negotiations with the PRC to immediately open direct transportation links. Regarding independence, the mainstream Pan-Blue position is to maintain the status quo, while refusing immediate reunification.[165] President Ma Ying-jeou stated that there will be no unification nor declaration of independence during his presidency.[187][188] As of 2009[update], Pan-Blue members usually seek to improve relationships with mainland China, with a current focus on improving economic ties.[189]
+
+The dominant political issue in Taiwan is its relationship with the PRC. For almost 60 years, there were no direct transportation links, including direct flights, between Taiwan and mainland China. This was a problem for many Taiwanese businesses that had opened factories or branches in mainland China. The former DPP administration feared that such links would lead to tighter economic and political integration with mainland China, and in the 2006 Lunar New Year Speech, President Chen Shui-bian called for managed opening of links. Direct weekend charter flights between Taiwan and mainland China began in July 2008 under the KMT government, and the first direct daily charter flights took off in December 2008.[190]
+
+Other major political issues include the passage of an arms procurement bill that the United States authorized in 2001.[191] In 2008, however, the United States were reluctant to send over more arms to Taiwan out of fear that it would hinder the recent improvement of ties between the PRC and the ROC.[192] Another major political issue is the establishment of a National Communications Commission to take over from the Government Information Office, whose advertising budget exercised great control over the media.[193]
+
+The politicians and their parties have themselves become major political issues. Corruption among some DPP administration officials had been exposed. In early 2006, President Chen Shui-bian was linked to possible corruption. The political effect on President Chen Shui-bian was great, causing a division in the DPP leadership and supporters alike. It eventually led to the creation of a political camp led by ex-DPP leader Shih Ming-teh which believed the president should resign. The KMT assets continue to be another major issue, as it was once the richest political party in the world.[194] Nearing the end of 2006, KMT's chairman Ma Ying-jeou was also hit by corruption controversies, although he has since then been cleared of any wrongdoings by the courts.[195] After completing his second term as President, Chen Shui-bian was charged with corruption and money laundering.[196] Following his conviction, he is serving a 17-year sentence in Taipei Prison.[197]
+
+Taiwan's leaders, including President Tsai and Premier William Lai, have repeatedly accused China of spreading fake news via social media to create divisions in Taiwanese society, influence voters and support candidates more sympathetic to Beijing ahead of the 2018 Taiwanese local elections.[198][199][200] China has been accused of conducting hybrid warfare against Taiwan.[201][202]
+
+Roughly 84% of Taiwan's population are descendants of Han Chinese immigrants from Qing China between 1661 and 1895. Another significant fraction descends from Han Chinese who immigrated from mainland China in the late 1940s and early 1950s. The shared cultural origin combined with several hundred years of geographical separation, some hundred years of political separation and foreign influences, as well as hostility between the rival ROC and PRC have resulted in national identity being a contentious issue with political overtones. Since democratic reforms and the lifting of martial law, a distinct Taiwanese identity (as opposed to Taiwanese identity as a subset of a Chinese identity) is often at the heart of political debates. Its acceptance makes the island distinct from mainland China, and therefore may be seen as a step towards forming a consensus for de jure Taiwan independence.[203] The pan-green camp supports a distinct Taiwanese identity, while the pan-blue camp supports a Chinese identity only.[186] The KMT has downplayed this stance in the recent years and now supports a Taiwanese identity as part of a Chinese identity.[204][205]
+
+According to a survey conducted in March 2009, 49% of the respondents consider themselves as Taiwanese only, and 44% of the respondents consider themselves as Taiwanese and Chinese. 3% consider themselves as only Chinese.[127] Another survey, conducted in Taiwan in July 2009, showed that 82.8% of respondents consider the ROC and the PRC as two separate countries with each developing on its own.[206] A survey conducted in December 2009 showed that 62% of the respondents consider themselves as Taiwanese only, and 22% of the respondents consider themselves as both Taiwanese and Chinese. 8% consider themselves as only Chinese. The survey also shows that among 18- to 29-year-old respondents, 75% consider themselves as Taiwanese only.[207]
+
+In a survey conducted by National Chengchi University published in 2020 of individuals over 20 who lived on the main island, 67.0% of respondents identified themselves exclusively as Taiwanese, 27.5% identified themselves as both Taiwanese and Chinese, and 2.4% identified themselves as Chinese.[208]
+
+Taiwan is, in practice, divided into 22 subnational divisions, each with a self-governing body led by an elected leader and a legislative body with elected members. Duties of local governments include social services, education, urban planning, public construction, water management, environmental protection, transport, public safety, and more.
+
+There are three types of subnational divisions: special municipalities, counties, and cities. Special municipalities and cities are further divided into districts for local administration. Counties are further divided into townships and county-administered cities which have elected mayors and councils, and share duties with the county. Some divisions are indigenous divisions which have different degrees of autonomy to standard ones. In addition, districts, cities and townships are further divided into villages and neighbourhoods.
+
+
+
+The Republic of China Army takes its roots in the National Revolutionary Army, which was established by Sun Yat-sen in 1925 in Guangdong with a goal of reunifying China under the Kuomintang. When the People's Liberation Army won the Chinese Civil War, much of the National Revolutionary Army retreated to Taiwan along with the government. It was later reformed into the Republic of China Army. Units which surrendered and remained in mainland China were either disbanded or incorporated into the People's Liberation Army.
+
+Taiwan and the United States signed the Sino-American Mutual Defense Treaty in 1954, and established the United States Taiwan Defense Command. About 30,000 US troops were stationed in Taiwan, until the United States established diplomatic relations with PRC in 1979.
+
+Today, Taiwan maintains a large and technologically advanced military, mainly as a defence to the constant threat of invasion by the People's Liberation Army using the Anti-Secession Law of the People's Republic of China as a pretext. This law authorizes the use of military force when certain conditions are met, such as a danger to mainlanders.[129]
+
+From 1949 to the 1970s, the primary mission of the Taiwanese military was to "retake mainland China" through Project National Glory. As this mission has transitioned away from attack because the relative strength of the PRC has massively increased, the ROC military has begun to shift emphasis from the traditionally dominant Army to the air force and navy.
+
+Control of the armed forces has also passed into the hands of the civilian government.[214][215] As the ROC military shares historical roots with the KMT, the older generation of high-ranking officers tends to have Pan-Blue sympathies. However, many have retired and there are many more non-mainlanders enlisting in the armed forces in the younger generations, so the political leanings of the military have moved closer to the public norm in Taiwan.[216]
+
+The ROC began a force reduction plan, Jingshi An (translated to streamlining program), to scale down its military from a level of 450,000 in 1997 to 380,000 in 2001.[217] As of 2009[update], the armed forces of the ROC number approximately 300,000,[218] with nominal reserves totalling 3.6 million as of 2015[update].[219] Conscription remains universal for qualified males reaching age eighteen, but as a part of the reduction effort many are given the opportunity to fulfill their draft requirement through alternative service and are redirected to government agencies or arms related industries.[220] Current plans call for a transition to a predominantly professional army over the next decade.[221][222] Conscription periods are planned to decrease from 14 months to 12.[223] In the last months of the Bush administration, Taipei took the decision to reverse the trend of declining military spending, at a time when most Asian countries kept on reducing their military expenditures. It also decided to strengthen both defensive and offensive capabilities. Taipei still keeps a large military apparatus relative to the island's population: military expenditures for 2008 were NTD 334 billion (approximately US $10.5 billion), which accounted for 2.94% of GDP.
+
+The armed forces' primary concern at this time, according to the National Defense Report, is the possibility of an invasion by the PRC, consisting of a naval blockade, airborne assault, and/or missile bombardment.[214] Four upgraded Kidd-class destroyers were purchased from the United States, and commissioned into the Republic of China Navy in 2005–2006, significantly upgrading Taiwan's protection from aerial attack and submarine hunting abilities.[224] The Ministry of National Defense planned to purchase diesel-powered submarines and Patriot anti-missile batteries from the United States, but its budget has been stalled repeatedly by the opposition-Pan-Blue Coalition controlled legislature. The military package was stalled from 2001 to 2007 where it was finally passed through the legislature and the US responded on 3 October 2008, with a $6.5 billion arms package including PAC III Anti-Air systems, AH-64D Apache Attack helicopters and other arms and parts.[225] A significant amount of military hardware has been bought from the United States, and, as of 2009[update], continues to be legally guaranteed by the Taiwan Relations Act.[146] In the past, France and the Netherlands have also sold military weapons and hardware to the ROC, but they almost entirely stopped in the 1990s under pressure of the PRC.[226][227]
+
+The first line of protection against invasion by the PRC is the ROC's own armed forces. Current ROC military doctrine is to hold out against an invasion or blockade until the US military responds.[228] There is, however, no guarantee in the Taiwan Relations Act or any other treaty that the United States will defend Taiwan, even in the event of invasion.[229] The joint declaration on security between the US and Japan signed in 1996 may imply that Japan would be involved in any response. However, Japan has refused to stipulate whether the "area surrounding Japan" mentioned in the pact includes Taiwan, and the precise purpose of the pact is unclear.[230] The Australia, New Zealand, United States Security Treaty (ANZUS Treaty) may mean that other US allies, such as Australia, could theoretically be involved.[231] In such a situation, Australia could potentially risk losing economic ties with China.[232]
+
+The quick industrialization and rapid growth of Taiwan during the latter half of the 20th century has been called the "Taiwan Miracle". Taiwan is one of the "Four Asian Tigers" alongside Hong Kong, South Korea and Singapore.
+
+Japanese rule prior to and during World War II brought changes in the public and private sectors, most notably in the area of public works, which enabled rapid communications and facilitated transport throughout much of the island. The Japanese also improved public education and made it compulsory for all residents of Taiwan. By 1945, hyperinflation was in progress in mainland China and Taiwan as a result of the war with Japan. To isolate Taiwan from it, the Nationalist government created a new currency area for the island, and began a price stabilization programme. These efforts significantly slowed inflation.
+
+When the KMT government fled to Taiwan it brought millions of taels (where 1 tael = 37.5 g or ~1.2 ozt) of gold and the foreign currency reserve of mainland China, which, according to the KMT, stabilized prices and reduced hyperinflation.[233] Perhaps more importantly, as part of its retreat to Taiwan, the KMT brought the intellectual and business elites from mainland China.[234] The KMT government instituted many laws and land reforms that it had never effectively enacted on mainland China. The government also implemented a policy of import-substitution, attempting to produce imported goods domestically.
+
+In 1950, with the outbreak of the Korean War, the United States began an aid programme which resulted in fully stabilized prices by 1952.[235] Economic development was encouraged by American economic aid and programmes such as the Joint Commission on Rural Reconstruction, which turned the agricultural sector into the basis for later growth. Under the combined stimulus of the land reform and the agricultural development programmes, agricultural production increased at an average annual rate of 4 per cent from 1952 to 1959, which was greater than the population growth, 3.6%.[236]
+
+In 1962, Taiwan had a (nominal) per-capita gross national product (GNP) of $170, placing its economy on a par with those of the Democratic Republic of the Congo. On a purchasing power parity (PPP) basis, its GDP per capita in the early 1960s was $1,353 (in 1990 prices). By 2011 per-capita GNP, adjusted for purchasing power parity (PPP), had risen to $37,000, contributing to a Human Development Index (HDI) equivalent to that of other developed countries.
+
+In 1974, Chiang Ching-kuo implemented the Ten Major Construction Projects, the beginning foundations that helped Taiwan transform into its current export driven economy. Since the 1990s, a number of Taiwan-based technology firms have expanded their reach around the world. Well-known international technology companies headquartered in Taiwan include personal computer manufacturers Acer Inc. and Asus, mobile phone maker HTC, as well as electronics manufacturing giant Foxconn, which makes products for Apple, Amazon, and Microsoft. Computex Taipei is a major computer expo, held since 1981.
+
+Today Taiwan has a dynamic, capitalist, export-driven economy with gradually decreasing state involvement in investment and foreign trade. In keeping with this trend, some large government-owned banks and industrial firms are being privatized.[237] Real growth in GDP has averaged about 8% during the past three decades. Exports have provided the primary impetus for industrialization. The trade surplus is substantial, and foreign reserves are the world's fifth largest.[238] The currency of Taiwan is the New Taiwan dollar.
+
+Since the beginning of the 1990s, the economic ties between Taiwan and the People's Republic of China have been very prolific. As of 2008[update], more than US$150 billion[239] have been invested in the PRC by Taiwanese companies, and about 10% of the Taiwanese labour force works in the PRC, often to run their own businesses.[240] Although the economy of Taiwan benefits from this situation, some have expressed the view that the island has become increasingly dependent on the mainland Chinese economy. A 2008 white paper by the Department of Industrial Technology states that "Taiwan should seek to maintain stable relation with China while continuing to protect national security, and avoiding excessive 'Sinicization' of Taiwanese economy."[241] Others argue that close economic ties between Taiwan and mainland China would make any military intervention by the PLA against Taiwan very costly, and therefore less probable.[242]
+
+Taiwan's total trade in 2010 reached an all-time high of US$526.04 billion, according to Taiwan's Ministry of Finance. Both exports and imports for the year reached record levels, totalling US$274.64 billion and US$251.4 billion, respectively.[243]
+
+In 2001, agriculture constituted only 2% of GDP, down from 35% in 1952.[244] Traditional labour-intensive industries are steadily being moved offshore and with more capital and technology-intensive industries replacing them. High-technology industrial parks have sprung up in every region in Taiwan. The ROC has become a major foreign investor in the PRC, Thailand, Indonesia, the Philippines, Malaysia, and Vietnam. It is estimated that some 50,000 Taiwanese businesses and 1,000,000 businesspeople and their dependents are established in the PRC.[245]
+
+Because of its conservative financial approach and its entrepreneurial strengths, Taiwan suffered little compared with many of its neighbours in the 1997 Asian financial crisis. Unlike its neighbours, South Korea and Japan, the Taiwanese economy is dominated by small and medium-sized businesses, rather than the large business groups. The global economic downturn, however, combined with poor policy co-ordination by the new administration and increasing bad debts in the banking system, pushed Taiwan into recession in 2001, the first whole year of negative growth since 1947. Due to the relocation of many manufacturing and labour-intensive industries to the PRC, unemployment also reached a level not seen since the 1970s oil crisis. This became a major issue in the 2004 presidential election. Growth averaged more than 4% in the 2002–2006 period and the unemployment rate fell below 4%.[246]
+
+The ROC often joins international organizations (especially ones that also include the People's Republic of China) under a politically neutral name. The ROC has been a member of governmental trade organizations such as the World Trade Organization under the name Separate Customs Territory of Taiwan, Penghu, Kinmen and Matsu (Chinese Taipei) since 2002.[247]
+
+The Ministry of Transportation and Communications of the Republic of China is the cabinet-level governing body of the transport network in Taiwan.
+
+Civilian transport in Taiwan is characterised by extensive use of scooters. In March 2019, 13.86 million were registered, twice that of cars.[248]
+
+Both highways and railways are concentrated near the coasts where the majority of the population resides, with 1,619 km (1,006 mi) of motorway.
+
+Railways in Taiwan are primarily used for passenger services, with Taiwan Railway Administration (TRA) operating a circular route and Taiwan High Speed Rail (THSR) running high speed services on the west coast. Urban transit systems include Taipei Metro, Kaohsiung Rapid Transit, Taoyuan Metro and New Taipei Metro.
+
+Major airports include Taiwan Taoyuan, Kaohsiung, Taipei Songshan and Taichung. There are currently seven airlines in Taiwan, the largest ones being China Airlines and EVA Air.
+
+There are four international seaports: Keelung, Kaohsiung, Taichung, and Hualien.
+
+Taiwan's higher education system was established by Japan during the colonial period. However, after the Republic of China took over in 1945, the system was promptly replaced by the same system as in mainland China which mixed features of the Chinese and American educational systems.[249]
+
+Taiwan is well known for adhering to the Confucian paradigm of valuing education as a means to improve one's socioeconomic position in society.[250][251] Heavy investment and a cultural valuing of education has catapulted the resource-poor nation consistently to the top of global education rankings. Taiwan is one of the top-performing countries in reading literacy, mathematics and sciences. In 2015, Taiwanese students achieved one of the world's best results in mathematics, science and literacy, as tested by the Programme for International Student Assessment (PISA), with the average student scoring 519, compared with the OECD average of 493, placing it seventh in the world.[252][253][254][255]
+
+The Taiwanese education system has been praised for various reasons, including its comparatively high test results and its major role in promoting Taiwan's economic development while creating one of the world's most highly educated workforces.[256][257] Taiwan has also been praised for its high university entrance rate where the university acceptance rate has increased from around 20 per cent before the 1980s to 49 per cent in 1996 and over 95 per cent since 2008, among the highest in Asia.[258][259][260] The nation's high university entrance rate has created a highly skilled workforce making Taiwan one of the most highly educated countries in the world with 68.5% of Taiwanese high school students going on to attend university.[261] Taiwan has a high percentage of its citizens holding a tertiary education degree where 45 per cent of Taiwanese aged 25–64 hold a bachelor's degree or higher compared with the average of 33 per cent among member countries of the Organisation for Economic Cooperation and Development (OECD).[260][262]
+
+On the other hand, the system has been criticised for placing excessive pressure on students while eschewing creativity and producing an excess supply of over-educated university graduates and a high graduate unemployment rate. With a large number of university graduates seeking a limited number of prestigious white collar jobs in an economic environment that is increasingly losing its competitive edge, this has led many graduates to be employed in lower end jobs with salaries far beneath their expectations.[263][251] Taiwan's universities have also been under criticism for not being able to fully meet the requirements and demands of Taiwan's 21st century fast-moving job market citing a skills mismatch among a large number of self-assessed, overeducated university graduates that don't fit the demands of the modern Taiwanese labour market.[264] The Taiwanese government has also received criticism for undermining the economy as it has been unable to produce enough jobs to meet the demands of numerous underemployed university graduates.[258][265]
+
+As the Taiwanese economy is largely science and technology based, the labour market demands people who have achieved some form of higher education, particularly related to science and engineering to gain a competitive edge when searching for employment. Although current Taiwanese law mandates only nine years of schooling, 95% of junior high graduates go on to attend a senior vocational high school, university, junior college, trade school, or other higher education institution.[261][266]
+
+Many Taiwanese students attend cram schools, or buxiban, to improve skills and knowledge on problem solving against exams of subjects like mathematics, nature science, history and many others. Courses are available for most popular subjects and include lectures, reviews, private tutorial sessions, and recitations.[267][268]
+
+As of 2018[update], the literacy rate in Taiwan is 98.87%.[269]
+
+Taiwan has a population of about 23.4 million,[270] most of whom are on the island proper. The remainder live on Penghu (101,758), Kinmen (127,723), and Matsu (12,506).[271]
+
+The figures below are the March 2019 estimates for the twenty most populous administrative divisions; a different ranking exists when considering the total metropolitan area populations (in such rankings the Taipei-Keelung metro area is by far the largest agglomeration).
+
+
+
+The ROC government reports that over 95% of the population is Han Chinese, of which the majority includes descendants of early Han Chinese immigrants who arrived in Taiwan in large numbers starting in the 18th century. Alternatively, the ethnic groups of Taiwan may be roughly divided among the Hoklo (70%), the Hakka (14%), the Waishengren (14%), and indigenous peoples (2%).[7]
+
+The Hoklo people are the largest ethnic group (70% of the total population), whose Han ancestors migrated from the coastal southern Fujian region across the Taiwan Strait starting in the 17th century. The Hakka comprise about 15% of the total population, and descend from Han migrants to Guangdong, its surrounding areas and Taiwan. Additional people of Han origin include and descend from the 2 million Nationalists who fled to Taiwan following the communist victory on the mainland in 1949.[7]
+
+The indigenous Taiwanese aborigines number about 533,600 and are divided into 16 groups.[272] The Ami, Atayal, Bunun, Kanakanavu, Kavalan, Paiwan, Puyuma, Rukai, Saisiyat, Saaroa, Sakizaya, Sediq, Thao, Truku and Tsou live mostly in the eastern half of the island, while the Yami inhabit Orchid Island.[273][274]
+
+Mandarin is the primary language used in business and education, and is spoken by the vast majority of the population. Traditional Chinese is used as the writing system.[275]
+
+70% of the population belong to the Hoklo ethnic group and speak Hokkien natively in addition to Mandarin. The Hakka group, comprising some 14–18% of the population, speak Hakka. Although Mandarin is the language of instruction in schools and dominates television and radio, non-Mandarin Chinese varieties have undergone a revival in public life in Taiwan, particularly since restrictions on their use were lifted in the 1990s.[275]
+
+Formosan languages are spoken primarily by the indigenous peoples of Taiwan. They do not belong to the Chinese or Sino-Tibetan language family, but to the Austronesian language family, and are written in Latin alphabet.[276] Their use among aboriginal minority groups has been in decline as usage of Mandarin has risen.[275] Of the 14 extant languages, five are considered moribund.[277]
+
+Taiwan is officially multilingual. A national language in Taiwan is legally defined as "a natural language used by an original people group of Taiwan and the Taiwan Sign Language".[4] As of 2019, policies on national languages are in early stages of implementation, with Hakka and indigenous languages designated as such.
+
+Estimated religious composition in 2020[278]
+
+The Constitution of the Republic of China protects people's freedom of religion and the practices of belief.[279] Freedom of religion in Taiwan is strong.
+
+In 2005, the census reported that the five largest religions were: Buddhism, Taoism, Yiguandao, Protestantism, and Roman Catholicism.[280] According to Pew Research, the religious composition of Taiwan in 2020[281] is estimated to become 43.8% Folk religions, 21.2% Buddhist, 13.7% Unaffiliated, 5.8% Christian and 15.5% other religions. Taiwanese aborigines comprise a notable subgroup among professing Christians: "...over 64% identify as Christian... Church buildings are the most obvious markers of Aboriginal villages, distinguishing them from Taiwanese or Hakka villages".[282] There has been a small Muslim community of Hui people in Taiwan since the 17th century.[283]
+
+Confucianism is a philosophy that deals with secular moral ethics, and serves as the foundation of both Chinese and Taiwanese culture. The majority of Taiwanese people usually combine the secular moral teachings of Confucianism with whatever religions they are affiliated with.
+
+As of 2009[update], there were 14,993 temples in Taiwan, approximately one place of worship per 1,500 residents. 9,202 of those temples were dedicated to Taoism and Buddhism. In 2008, Taiwan had 3,262 Churches, an increase of 145.[284]
+
+A significant percentage of the population of Taiwan is nonreligious. Taiwan's strong human rights protections, lack of state-sanctioned discrimination, and generally high regard for freedom of religion or belief earned it a joint #1 ranking in the 2018 Freedom of Thought Report, alongside the Netherlands and Belgium.[285]
+
+Taiwan is clearly an outlier in the top 3, all-clear countries. It is non-European, and demographically much more religious. But in its relatively open, democratic and tolerant society we have recorded no evidence of laws or social discrimination against members of the non-religious minority.[286]
+
+On 24 May 2017, the Constitutional Court ruled that then-current marriage laws had been violating the Constitution by denying Taiwanese same-sex couples the right to marry. The Court ruled that if the Legislative Yuan did not pass adequate amendments to Taiwanese marriage laws within two years, same-sex marriages would automatically become lawful in Taiwan.[287] On 17 May 2019, Taiwan's parliament approved a bill legalising same-sex marriage, making it the first in Asia to do so.[288][289]
+
+Health care in Taiwan is managed by the Bureau of National Health Insurance (BNHI).[290]
+
+The current programme was implemented in 1995, and is considered to be a form of social insurance. The government health insurance programme maintains compulsory insurance for citizens who are employed, impoverished, unemployed, or victims of natural disasters with fees that correlate to the individual and/or family income; it also maintains protection for non-citizens working in Taiwan. A standard method of calculation applies to all persons and can optionally be paid by an employer or by individual contributions.[291]
+
+BNHI insurance coverage requires co-payment at the time of service for most services unless it is a preventative health service, for low-income families, veterans, children under three years old, or in the case of catastrophic diseases. Low income households maintain 100% premium coverage by the BNHI and co-pays are reduced for disabled or certain elderly people.[citation needed]
+
+According to a recently published survey, out of 3,360 patients surveyed at a randomly chosen hospital, 75.1% of the patients said they are "very satisfied" with the hospital service; 20.5% said they are "okay" with the service. Only 4.4% of the patients said they are either "not satisfied" or "very not satisfied" with the service or care provided.[292]
+
+Taiwan has its own authority for disease control, and during the SARS outbreak in March 2003 there were 347 confirmed cases. During the outbreak the disease control bureaux and local governments set up monitored stations throughout public transportation, recreational sites and other public areas. With full containment in July 2003, there has not been a case of SARS since.[293]
+
+As of 2017[update], the BNHI Facility Contract Distribution facilities total 28,339, including:[294]
+
+Basic coverage areas of the insurance include:
+
+In 2004, the infant mortality rate was 5.3 with 15 physicians and 63 hospital beds per 10,000 people. The life expectancy for males was 73.5 years and 79.7 years for females according to the World Health Report.
+
+In July 2013, the Department of Health was restructured as the Ministry of Health and Welfare.[295]
+
+Source: UN World Population Prospects[296]
+
+The cultures of Taiwan are a hybrid blend of various sources, incorporating elements of traditional Chinese culture, attributable to the historical and ancestral origin of the majority of its current residents, Japanese culture, traditional Confucianist beliefs, and increasingly Western values.
+
+After their move to Taiwan, the Kuomintang imposed an official interpretation of traditional Chinese culture over Taiwan. The government launched a policy promoting Chinese calligraphy, traditional Chinese painting, folk art, and Chinese opera.[citation needed]
+
+The status of Taiwanese culture is debated.[297] It is disputed whether Taiwanese culture is a regional form of Chinese culture or a distinct culture. Reflecting the continuing controversy surrounding the political status of Taiwan, politics continues to play a role in the conception and development of a Taiwanese cultural identity, especially in the prior dominant frame of a Taiwanese and Chinese dualism. In recent years, the concept of Taiwanese multiculturalism has been proposed as a relatively apolitical alternative view, which has allowed for the inclusion of mainlanders and other minority groups into the continuing re-definition of Taiwanese culture as collectively held systems of meaning and customary patterns of thought and behaviour shared by the people of Taiwan.[298] Identity politics, along with the over one hundred years of political separation from mainland China, has led to distinct traditions in many areas, including cuisine and music.
+
+One of Taiwan's greatest attractions is the National Palace Museum, which houses more than 650,000 pieces of Chinese bronze, jade, calligraphy, painting, and porcelain and is considered one of the greatest collections of Chinese art and objects in the world.[299] The KMT moved this collection from the Forbidden City in Beijing in 1933 and part of the collection was eventually transported to Taiwan during the Chinese Civil War. The collection, estimated to be one-tenth of China's cultural treasures, is so extensive that only 1% is on display at any time. The PRC had said that the collection was stolen and has called for its return, but the ROC has long defended its control of the collection as a necessary act to protect the pieces from destruction, especially during the Cultural Revolution. Relations regarding this treasure have warmed recently; Beijing Palace Museum Curator Zheng Xinmiao said that artefacts in both Chinese and Taiwanese museums are "China's cultural heritage jointly owned by people across the Taiwan Strait".[300]
+
+The classical music culture in Taiwan is highly developed and features artists such as violinist Cho-Liang Lin, pianist Ching-Yun Hu, and the Lincoln Center Chamber Music Society Artist Director Wu Han. Karaoke, drawn from contemporary Japanese culture, is extremely popular in Taiwan, where it is known as KTV. KTV businesses operate in a hotel-like style, renting out small rooms and ballrooms according to the number of guests in a group. Many KTV establishments partner with restaurants and buffets to form all-encompassing and elaborate evening affairs for families, friends, or businessmen. Tour buses that travel around Taiwan have several TV's, equipped not for watching movies, but primarily for singing Karaoke. The entertainment counterpart of a KTV is an MTV, being found much less frequently out of the city. There, movies out on DVD can be selected and played in a private theatre room. However, MTV, more so than KTV, has a growing reputation for being a place that young couples will go to be alone and intimate.
+
+Taiwan has a high density of 24-hour convenience stores, which, in addition to the usual services, provide services on behalf of financial institutions or government agencies such as collection of parking fees, utility bills, traffic violation fines, and credit card payments.[301] They also provide a service for mailing packages.
+
+Taiwanese culture has also influenced other cultures. Bubble tea and milk tea are available in Singapore, Malaysia, the Philippines, Australia, Europe, and North America. Taiwanese television shows are popular in Singapore, Malaysia, and other Asian countries. Taiwanese films have won various international awards at film festivals around the world. Ang Lee, a Taiwanese director, has directed critically acclaimed films such as: Crouching Tiger, Hidden Dragon; Eat Drink Man Woman; Sense and Sensibility; Brokeback Mountain; Life of Pi; and Lust, Caution. Other famous Taiwanese directors include Tsai Ming-liang, Edward Yang, and Hou Hsiao-hsien.
+
+Baseball is Taiwan's national sport and is a popular spectator sport. There have been fifteen Taiwanese Major League Baseball players in the United States, notably including pitchers Chien-Ming Wang and Wei-Yin Chen. The Chinese Professional Baseball League in Taiwan was established in 1989,[302] and eventually absorbed the competing Taiwan Major League in 2003. As of 2015[update], the CPBL has four teams with average attendance over 5,000 per game.[303]
+
+Besides baseball, basketball is Taiwan's other major sport.[304]
+
+Taiwan participates in international sporting organizations and events under the name of "Chinese Taipei" due to its political status. In 2009, Taiwan hosted two international sporting events on the island. The World Games 2009 were held in Kaohsiung between 16 and 26 July 2009. Taipei hosted the 21st Summer Deaflympics in September of the same year. Furthermore, Taipei hosted the Summer Universiade in 2017.[305]
+
+Taekwondo has become a mature and successful sport in Taiwan in recent years. In the 2004 Olympics, Chen Shih-hsin and Chu Mu-yen won the first two gold medals in women's flyweight event and men's flyweight event, respectively. Subsequent taekwondo competitors such as Yang Shu-chun have strengthened Taiwan's taekwondo culture.
+
+Taiwan has a long history of strong international presence in table tennis. Chen Pao-pei was a gold medalist in the women's singles at the Asian Table Tennis Championships in 1953 and gold medalist with Chiang Tsai-yun in the 1957 women's doubles and women's team events. Lee Kuo-ting won the men's singles at the 1958 Asian Table Tennis Championships. More recently Chen Chien-an won the 2008 World Junior Table Tennis Championships in singles and pairing with Chuang Chih-yuan won the men's doubles in 2013 at the 52nd World Table Tennis Championships. Playing for Taiwan Chen Jing won a bronze medal at the 1996 Olympic Games and a silver medal at the 2000 Olympic Games. 17-year-old Lin Yun-Ju upset both reigning world champion Ma Long and world ranked No. 3 Fan Zhendong to win the 2019 men's singles in the T2 Diamond Series in Malaysia.[306][307][308][309]
+
+In lawn tennis, Hsieh Su-wei is the country's most successful player, having been ranked inside the top 25 in singles in the WTA rankings.[310] She became joint No. 1 in doubles with her partner Peng Shuai in 2014.[311] The sisters Chan Yung-jan (Latisha Chan) and Chan Hao-ching are doubles specialists. They won their 13th WTA tournament together at the 2019 Eastbourne International,[312] the second-highest number of wins for a pair of sisters after the Williams sisters.[313] Latisha Chan became joint No. 1 with partner Martina Hingis in 2017.[314] The most successful men's player was Lu Yen-hsun, who reached No. 33 in the ATP rankings in 2010.[315]
+
+Taiwan is also a major Asian country for Korfball. In 2008, Taiwan hosted the World Youth Korfball Championship and took the silver medal.[316] In 2009, Taiwan's korfball team won a bronze medal at the World Game.[317]
+
+Yani Tseng is the most famous Taiwanese professional golfer currently playing on the US-based LPGA Tour. She is the youngest player ever, male or female, to win five major championships and was ranked number 1 in the Women's World Golf Rankings for 109 consecutive weeks from 2011 to 2013.[318][319][320]
+
+The standard Gregorian calendar is used for most purposes in Taiwan. The year is often denoted by the Minguo era system which starts in 1912, the year the ROC was founded. 2020 is year 109 Minguo (民國109年). This notation is most used by the government. The East Asian date format is used in Chinese.[321]
+
+Prior to standardisation in 1929, the official calendar was a lunisolar system, which remains in use today for traditional festivals such as the Lunar New Year, the Lantern Festival, and the Dragon Boat Festival.[322]

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+Formula One (also known as Formula 1 or F1) is the highest class of international single-seater auto racing sanctioned by the Fédération Internationale de l'Automobile (FIA) and owned by the Formula One Group. The World Drivers' Championship, which became the FIA Formula One World Championship in 1981, has been one of the premier forms of racing around the world since its inaugural season in 1950. The word "formula" in the name refers to the set of rules to which all participants' cars must conform.[1] A Formula One season consists of a series of races, known as Grands Prix (French for ''grand prizes' or 'great prizes''), which take place worldwide on purpose-built circuits and on public roads.
+
+The results of each race are evaluated using a points system to determine two annual World Championships: one for drivers, the other for constructors. Drivers must hold valid Super Licences, the highest class of racing licence issued by the FIA.[2] The races must run on tracks graded "1" (formerly "A"), the highest grade-rating issued by the FIA.[2] Most events occur in rural locations on purpose-built tracks, but several events take place on city streets.
+
+Formula One cars are the fastest regulated road-course racing cars in the world, owing to very high cornering speeds achieved through the generation of large amounts of aerodynamic downforce. The cars underwent major changes in 2017,[3] allowing wider front and rear wings, and wider tyres, resulting in peak cornering forces near 6.5 lateral g and top speeds of up to approximately 370 km/h (230 mph).[4][5] As of 2019[update] the hybrid engines are limited in performance to a maximum of 15,000 rpm, the cars are very dependent on electronics and aerodynamics, suspension and tyres. Traction control and other driving aids have been banned since 2008.[6]
+
+While Europe is the sport's traditional base, the championship operates globally, with 11 of the 21 races in the 2019 season taking place outside Europe. With the annual cost of running a mid-tier team—designing, building, and maintaining cars, pay, transport—being US$120 million,[7]  its financial and political battles are widely reported. Its high profile and popularity have created a major merchandising environment, which has resulted in large investments from sponsors and budgets (in the hundreds of millions for the constructors). On 23 January 2017 Liberty Media confirmed the completion of the acquisition of Delta Topco, the company that controls Formula One, from private-equity firm CVC Capital Partners for $8 billion.[8][9]
+
+A $145m budget cap will be introduced for each Formula One team, starting in the 2021 season, so as to ensure fair competition and sustainable development of the sport.[10]
+
+The Formula One series originated with the European Championship of Grand Prix motor racing (q.v. for pre-1947 history) of the 1920s and 1930s. The formula comprises a set of rules that all participants' cars must meet. Formula One was a new formula agreed upon during 1946 after World War II, with the first non-championship races taking place that year. The first Formula 1 race was the 1946 Turin Grand Prix. A number of Grand Prix racing organisations had laid out rules for a world championship before the war, but due to the suspension of racing during the conflict, the World Drivers' Championship did not become formalised until 1947. The first world championship race took place at  Silverstone in the United Kingdom in 1950. A championship for constructors followed in 1958. National championships existed in South Africa and the UK in the 1960s and 1970s. Non-championship Formula One events were held[by whom?] for many years, but due to the increasing cost of competition, the last of these occurred in 1983.[11] On 26 November 2017 Formula One unveiled its new logo, following the 2017 season finale in Abu Dhabi during the Abu Dhabi Grand Prix at Yas Marina Circuit. The new logo replaced F1's iconic "flying one", which had been the sport's trademark since 1993.[12]
+
+After a hiatus in European motor racing brought about by the outbreak of World War II in Europe in 1939, the Italian Giuseppe Farina in his Alfa Romeo won the first World Championship for Drivers in 1950, narrowly defeating his  Argentine teammate Juan Manuel Fangio. However, Fangio won the title in 1951, 1954, 1955, 1956, and 1957 (his record of five World Championship titles stood for 45 years until German driver Michael Schumacher took his sixth title in 2003). Fangio's streak was interrupted (after an injury) by two-time champion Alberto Ascari of  Ferrari. Although the UK's Stirling Moss was able to compete regularly, he was never able to win the world championship, and is now[update] widely considered statistically to be the greatest driver never to have won the title. In a seven-year span between 1955 and 1961 Moss finished as championship runner-up four times and in third place the other three times.[13][14] Fangio, however, has a reputation for dominating Formula One's first decade and has long been considered[by whom?] the "Grand Master" of Formula One.
+
+This period featured teams managed by road-car manufacturers Alfa Romeo, Ferrari,  Mercedes-Benz, and Maserati; all of which had competed before the war. The first seasons featured pre-war cars like Alfa's 158. They were  front-engined, with narrow tyres and 1.5-litre supercharged or 4.5-litre naturally aspirated engines. The 1952 and 1953 World Championships were run to Formula Two regulations, for smaller, less powerful cars, due to concerns over the paucity of Formula One cars available.[15][16] When a new Formula One formula, for engines limited to 2.5 litres, was reinstated to the world championship for 1954, Mercedes-Benz introduced the advanced  W196, which featured innovations such as desmodromic valves and fuel injection as well as enclosed streamlined bodywork. Mercedes drivers won the championship for two years, before the team withdrew from all motorsport in the wake of the 1955 Le Mans disaster.[17]
+
+An era of British dominance was ushered in by Mike Hawthorn and Vanwall's championship wins in 1958, although Stirling Moss had been at the forefront of the sport without ever securing the world title. Between Hawthorn, Jim Clark, Jackie Stewart, John Surtees and Graham Hill, British drivers won nine Drivers' Championships and British teams won fourteen Constructors' Championship titles between 1958 and 1974. The iconic British Racing Green Lotus, with a revolutionary aluminium-sheet monocoque chassis instead of the traditional space-frame design, was the dominant car, and in 1968, the team broke new boundaries, when they were the first to carry advertising on their cars.[18]
+
+The first major technological development, Bugatti's re-introduction of mid-engined cars (following Ferdinand Porsche's pioneering Auto Unions of the 1930s), occurred with the Type 251, which was unsuccessful. Australian Jack Brabham, world champion during 1959, 1960, and 1966, soon proved the mid-engined design's superiority. By 1961, all regular competitors had switched to mid-engined cars. The Ferguson P99, a four-wheel drive design, was the last front-engined F1 car to enter a world championship race. It was entered in the 1961 British Grand Prix, the only front-engined car to compete that year.[19]
+
+During 1962, Lotus introduced a car with an aluminium-sheet monocoque chassis instead of the traditional space-frame design. This proved to be the greatest technological breakthrough since the introduction of mid-engined cars. During 1968, Rhodesian duo John Love and Sam Tingle were the first to run cigarette sponsorship on their cars, which ran in orange, brown and gold Team Gunston colours in the South African Grand Prix on 1 January 1968, five months before Lotus painted an Imperial Tobacco livery on their cars, thus introducing sponsorship to the sport.[20][21]
+
+Aerodynamic downforce slowly gained importance in car design with the appearance of aerofoils during the late 1960s. During the late 1970s, Lotus introduced ground-effect aerodynamics (previously used on Jim Hall's Chaparral 2J during 1970) that provided enormous downforce and greatly increased cornering speeds. So great were the aerodynamic forces pressing the cars to the track (up to five times the car's weight), extremely stiff springs were needed to maintain a constant ride height, leaving the suspension virtually solid, depending entirely on the tyres for any small amount of cushioning of the car and driver from irregularities of the road surface.[22]
+
+Beginning in the 1970s, Bernie Ecclestone rearranged the management of Formula One's commercial rights; he is widely credited with transforming the sport into the multibillion-dollar business it now is.[23][24] When Ecclestone bought the Brabham team during 1971, he gained a seat on the Formula One Constructors' Association and during 1978 he became its president. Previously, the circuit owners controlled the income of the teams and negotiated with each individually; however Ecclestone persuaded the teams to "hunt as a pack" through FOCA.[24] He offered Formula One to circuit owners as a package, which they could take or leave. In return for the package, almost all that was required was to surrender trackside advertising.[23]
+
+The formation of the Fédération Internationale du Sport Automobile (FISA) during 1979 set off the FISA–FOCA controversy, during which FISA and its president Jean-Marie Balestre disputed repeatedly with FOCA over television revenues and technical regulations.[25] The Guardian said of FOCA that Ecclestone and Max Mosley "used it to wage a guerrilla war with a very long-term aim in view". FOCA threatened to establish a rival series, boycotted a Grand Prix and FISA withdrew its sanction from races.[23] The result was the 1981 Concorde Agreement, which guaranteed technical stability, as teams were to be given reasonable notice of new regulations.[26] Although FISA asserted its right to the TV revenues, it handed the administration of those rights to FOCA.[27]
+
+FISA imposed a ban on ground-effect aerodynamics during 1983.[28] By then, however, turbocharged engines, which Renault had pioneered in 1977, were producing over 520 kW (700 bhp) and were essential to be competitive. By 1986, a BMW turbocharged engine achieved a flash reading of 5.5 bar pressure, estimated to be over 970 kW (1,300 bhp) in qualifying for the Italian Grand Prix. The next year, power in race trim reached around 820 kW (1,100 bhp), with boost pressure limited to only 4.0 bar.[29] These cars were the most powerful open-wheel circuit racing cars ever. To reduce engine power output and thus speeds, the FIA limited fuel tank capacity in 1984, and boost pressures in 1988, before banning turbocharged engines completely in 1989.[30]
+
+The development of electronic driver aids began during the 1980s. Lotus began to develop a system of active suspension, which first appeared during 1982 on the Lotus 91. By 1987, this system had been perfected and was driven to victory by Ayrton Senna in the Monaco Grand Prix that year. In the early 1990s other teams followed suit and semi-automatic gearboxes and traction control were a natural progression. The FIA, due to complaints that technology was determining the outcome of races more than driver skill, banned many such aids for 1994. This resulted in cars that were previously dependent on electronic aids becoming very "twitchy" and difficult to drive (particularly the Williams FW16). Many observers felt the ban on driver aids was in name only as they "proved difficult to police effectively".[31]
+
+The teams signed a second Concorde Agreement during 1992 and a third in 1997, which expired on the last day of 2007.[32]
+
+On the track, the McLaren and Williams teams dominated the 1980s and 1990s, with Brabham also being competitive during the early part of the 1980s, winning two Drivers' Championships with Nelson Piquet. Powered by Porsche, Honda, and Mercedes-Benz, McLaren won sixteen championships (seven constructors' and nine drivers') in that period, while Williams used engines from Ford, Honda, and Renault to also win sixteen titles (nine constructors' and seven drivers'). The rivalry between racers Ayrton Senna and Alain Prost became F1's central focus during 1988, and continued until Prost retired at the end of 1993. Senna died at the 1994 San Marino Grand Prix after crashing into a wall on the exit of the notorious curve Tamburello, having taken over Prost's lead drive at Williams that year. The FIA worked to improve the sport's safety standards since that weekend, during which Roland Ratzenberger also lost his life in an accident during Saturday qualifying. No driver had died of injuries sustained on the track at the wheel of a Formula One car for 20 years, until the 2014 Japanese Grand Prix where Jules Bianchi collided with a recovery vehicle after aquaplaning off the circuit. Since 1994, three track marshals have lost their lives, one at the 2000 Italian Grand Prix,[33] the second at the 2001 Australian Grand Prix[33] and the third at the 2013 Canadian Grand Prix.
+
+Since the deaths of Senna and Ratzenberger, the FIA has used safety as a reason to impose rule changes that otherwise, under the Concorde Agreement, would have had to be agreed upon by all the teams – most notably the changes introduced for 1998. This so-called 'narrow track' era resulted in cars with smaller rear tyres, a narrower track overall, and the introduction of grooved tyres to reduce mechanical grip. There were to be four grooves on the front (three in the first year) and rear that ran through the entire circumference of the tyre. The objective was to reduce cornering speeds and to produce racing similar to rainy conditions by enforcing a smaller contact patch between tyre and track. This, according to the FIA, was to reduce cornering speeds in the interest of safety.[34]
+
+Results were mixed as the lack of mechanical grip resulted in the more ingenious designers clawing back the deficit with aerodynamic grip – pushing more force onto the tyres through wings and aerodynamic devices, which in turn resulted in less overtaking as these devices tended to make the wake behind the car 'dirty' (turbulent), preventing other cars from following closely due to their dependence on 'clean' air to make the car stick to the track. The grooved tyres also had the unfortunate side effect of initially being of a harder compound to be able to hold the grooved tread blocks, which resulted in spectacular accidents in times of aerodynamic grip failure as the harder compound could not grip the track as well.
+
+Drivers from McLaren, Williams, Renault (formerly Benetton), and Ferrari, dubbed the "Big Four", won every World Championship from 1984 to 2008. The teams won every Constructors' Championship from 1979 to 2008 as well as placing themselves as the top four teams in the Constructors' Championship in every season between 1989 and 1997, and winning every race but one (the 1996 Monaco Grand Prix) between 1988 and 1997. Due to the technological advances of the 1990s, the cost of competing in Formula One increased dramatically. This increased financial burdens, combined with the dominance of four teams (largely funded by big car manufacturers such as Mercedes-Benz), caused the poorer independent teams to struggle not only to remain competitive, but to stay in business, and forced several teams to withdraw. Since 1990, twenty-eight teams have withdrawn from Formula One. This has prompted former Jordan owner Eddie Jordan to say that the days of competitive privateers are over.[35]
+
+Michael Schumacher and Ferrari won five consecutive Drivers' Championships (2000–2004) and six consecutive Constructors' Championships (1999–2004). Schumacher set many new records, including those for Grand Prix wins (91), wins in a season (thirteen of eighteen), and most Drivers' Championships (seven).[36] Schumacher's championship streak ended on 25 September 2005, when Renault driver Fernando Alonso became Formula One's youngest champion at that time (until Lewis Hamilton in 2008 and followed by Sebastian Vettel in 2010). During 2006, Renault and Alonso won both titles again. Schumacher retired at the end of 2006 after sixteen years in Formula One, but came out of retirement for the 2010 season, racing for the newly formed Mercedes works team, following the rebrand of Brawn GP.
+
+During this period, the championship rules were changed frequently by the FIA with the intention of improving the on-track action and cutting costs.[37] Team orders, legal since the championship started during 1950, were banned during 2002, after several incidents, in which teams openly manipulated race results, generating negative publicity, most famously by Ferrari at the 2002 Austrian Grand Prix. Other changes included the qualifying format, the points scoring system, the technical regulations, and rules specifying how long engines and tyres must last. A "tyre war" between suppliers Michelin and Bridgestone saw lap times fall, although at the 2005 United States Grand Prix at Indianapolis, seven out of ten teams did not race when their Michelin tyres were deemed unsafe for use, leading to Bridgestone becoming the sole tyre supplier to Formula One for the 2007 season. During 2006, Max Mosley outlined a "green" future for Formula One, in which efficient use of energy would become an important factor.[38]
+
+Since 1983, Formula One had been dominated by specialist race teams like Williams, McLaren, and Benetton, using engines supplied by large car manufacturers like Mercedes-Benz, Honda, Renault, and Ford. Starting in 2000, with Ford's creation of the largely unsuccessful Jaguar team, new manufacturer-owned teams entered Formula One for the first time since the departure of Alfa Romeo and Renault at the end of 1985. By 2006, the manufacturer teams—Renault, BMW, Toyota, Honda, and Ferrari—dominated the championship, taking five of the first six places in the Constructors' Championship. The sole exception was McLaren, which at the time was part-owned by Mercedes-Benz. Through the Grand Prix Manufacturers Association (GPMA), they negotiated a larger share of Formula One's commercial profit and a greater say in the running of the sport.[39]
+
+In 2008 and 2009, Honda, BMW, and Toyota all withdrew from Formula One racing within the space of a year, blaming the economic recession. This resulted in the end of manufacturer dominance within the sport. The Honda F1 team went through a management buyout to become Brawn GP with Ross Brawn and Nick Fry running and owning the majority of the organisation. Brawn GP went through a painful size reduction, laying off hundreds of employees, but eventually won the year's world championships with Jenson Button and Rubens Barrichello. BMW F1 was bought out by the original founder of the team, Peter Sauber. The Lotus F1 Team[40] were another, formerly manufacturer-owned team that reverted to "privateer" ownership, together with the buy-out of the Renault team by Genii Capital investors. A link with their previous owners still survived however, with their car continuing to be powered by a Renault Power Unit until 2014.
+
+McLaren also announced that it was to reacquire the shares in its team from Mercedes-Benz (McLaren's partnership with Mercedes was reported to have started to sour with the McLaren Mercedes SLR road car project and tough F1 championships which included McLaren being found guilty of spying on Ferrari). Hence, during the 2010 season, Mercedes-Benz re-entered the sport as a manufacturer after its purchase of Brawn GP, and split with McLaren after 15 seasons with the team. This left Mercedes-Benz, Renault, McLaren, and Ferrari as the only car manufacturers in the sport, although both McLaren and Ferrari began as racing teams rather than manufacturers.
+
+To compensate for the loss of manufacturer teams, four new teams were accepted entry into the 2010 season ahead of a much anticipated 'cost-cap' (see below). Entrants included a reborn Team Lotus – which was led by a Malaysian consortium including Tony Fernandes, the boss of Air Asia; Hispania Racing – the first Spanish Formula One team; as well as Virgin Racing – Richard Branson's entry into the series following a successful partnership with Brawn the year before. They were also joined by the US F1 Team, which planned to run out of the United States as the only non-European based team in the sport. Financial issues befell the squad before they even made the grid. Despite the entry of these new teams, the proposed cost-cap was repealed and these teams – who did not have the budgets of the midfield and top-order teams – ran around at the back of the field until they inevitably collapsed; HRT in 2012, Caterham (formerly Lotus) in 2014 and Manor (formerly Virgin then Marussia), having survived falling into administration in 2014, went under at the end of 2016.
+
+A major rule shake-up in 2014 saw the 2.4 litre naturally aspirated V8 engines replaced by 1.6 litre turbocharged hybrid power units. This prompted Honda to return to the sport in 2015 as the championship's fourth engine manufacturer. Mercedes emerged as the dominant force after the rule shake-up, with Lewis Hamilton winning the championship closely followed by his main rival and teammate, Nico Rosberg, with the team winning 16 out of the 19 races that season (all other victories coming from Daniel Ricciardo of Red Bull). 2014 also saw a financial crisis which resulted in the backmarker Marussia and Caterham teams being put into administration, alongside the uncertain futures of Force India and Sauber. Marussia returned under the Manor name in 2015, a season in which Ferrari were the only challenger to Mercedes, with Vettel taking victory in the three Grands Prix Mercedes did not win.[41]
+
+In the 2016 season, Haas joined the grid. The season began in dominant fashion for Nico Rosberg, winning the first 4 Grands Prix. His charge was halted by Max Verstappen, who took his maiden win in Spain in his debut race for Red Bull. After that, the reigning champion Lewis Hamilton decreased the point gap between him and Rosberg to only one point, before taking the championship lead heading into the summer break. Following the break, the 1–2 positioning remained constant until an engine failure for Hamilton in Malaysia left Rosberg in a commanding lead that he would not relinquish in the 5 remaining races. Having won the title by a mere 5 points, Rosberg retired from Formula One at season's end, becoming the first driver since Alain Prost in 1993 to retire after winning the Drivers' Championship. The final team remaining from the 2010 new entries process, Manor Racing, withdrew from the sport following the 2016 season, having lost 10th in the Constructors' Championship to Sauber with one race remaining, leaving the grid at 20 cars as Liberty Media took control of the series in the off-season.
+
+Recent years have seen an increase in car manufacturer presence in the sport. After Honda's return as an engine manufacturer in 2015, Renault came back as a team in 2016 after buying back the Lotus F1 team. In 2018, Aston Martin and Alfa Romeo became Red Bull and Sauber's title sponsors, respectively. Sauber was rebranded as Alfa Romeo Racing for the 2019 season, while Racing Point part-owner Lawrence Stroll bought a stake in Aston Martin to rebrand the Racing Point team as Aston Martin for 2021.
+
+The battle for control of Formula One was contested between the Fédération Internationale du Sport Automobile (FISA), at the time an autonomous subcommittee of the FIA, and FOCA (the Formula One Constructors' Association).
+
+The beginnings of the dispute are numerous, and many of the underlying reasons may be lost in history. The teams (excepting Ferrari and the other major manufacturers – Renault and Alfa Romeo in particular) were of the opinion that their rights and ability to compete against the larger and better funded teams were being negatively affected by a perceived bias on the part of the controlling organisation (FISA) toward the major manufacturers.
+
+In addition, the battle revolved around the commercial aspects of the sport (the FOCA teams were unhappy with the disbursement of proceeds from the races) and the technical regulations which, in FOCA's opinion, tended to be malleable according to the nature of the transgressor more than the nature of the transgression.
+
+The war culminated in a FOCA boycott of the 1982 San Marino Grand Prix months later. In theory, all FOCA teams were supposed to boycott the Grand Prix as a sign of solidarity and complaint at the handling of the regulations and financial compensation (and extreme opposition to the accession of Balestre to the position of FISA president: both Colin Chapman of Lotus and Frank Williams of Williams stated clearly that they would not continue in Formula One with Balestre as its governor).[original research?] In practice, several of the FOCA teams backed out of the boycott, citing "sponsor obligations". Notable among these were the Tyrrell and Toleman teams.
+
+During the 2009 season of Formula One, the sport was gripped in a governance crisis. The FIA President Max Mosley proposed numerous cost-cutting measures for the following season, including an optional budget cap for the teams;[42] teams electing to take the budget cap would be granted greater technical freedom, adjustable front and rear wings and an engine not subject to a rev limiter.[42] The Formula One Teams Association (FOTA) believed that allowing some teams to have such technical freedom would have created a 'two-tier' championship, and thus requested urgent talks with the FIA. However, talks broke down and FOTA teams announced, with the exception of Williams and Force India,[43][44] that 'they had no choice' but to form a breakaway championship series.[44]
+
+On 24 June, an agreement was reached between Formula One's governing body and the teams to prevent a breakaway series. It was agreed teams must cut spending to the level of the early 1990s within two years; exact figures were not specified,[45] and Max Mosley agreed he would not stand for re-election to the FIA presidency in October.[46] Following further disagreements, after Max Mosley suggested he would stand for re-election,[47] FOTA made it clear that breakaway plans were still being pursued. On 8 July, FOTA issued a press release stating they had been informed they were not entered for the 2010 season,[48] and an FIA press release said the FOTA representatives had walked out of the meeting.[49] On 1 August, it was announced FIA and FOTA had signed a new Concorde Agreement, bringing an end to the crisis and securing the sport's future until 2012.[50]
+
+The terms "Formula One race" and "World Championship race" are now effectively synonymous; since 1984, every Formula One race has counted towards an official FIA World Championship, and every World Championship race has been held to Formula One regulations.[51] In the earlier history of Formula One, many races took place outside the World Championship, and local championships run to Formula One regulations also occurred. These events often took place on circuits that were not always suitable for the World Championship, and featured local cars and drivers as well as those competing in the championship.[11]
+
+In the early years of Formula One, before the world championship was established, there were around twenty races held from late Spring to early Autumn in Europe, although not all of these were considered significant. Most competitive cars came from Italy, particularly Alfa Romeo. After the start of the world championship, these non-championship races continued. In the 1950s and 1960s, there were many Formula One races which did not count for the World Championship; in 1950 a total of twenty-two Formula One races were held, of which only six counted towards the World Championship.[51] In 1952 and 1953, when the world championship was run to Formula Two regulations, non-championship events were the only Formula One races that took place.
+
+Some races, particularly in the UK, including the Race of Champions, Oulton Park International Gold Cup and the International Trophy, were attended by the majority of the world championship contenders. Other smaller events were regularly held in locations not part of the championship, such as the Syracuse and Danish Grands Prix, although these only attracted a small amount of the championship teams and relied on private entries and lower Formula cars to make up the grid.[11] These became less common through the 1970s and 1983 saw the last non-championship Formula One race; the 1983 Race of Champions at Brands Hatch, won by reigning World Champion Keke Rosberg in a Williams-Cosworth in a close fight with American Danny Sullivan.[11]
+
+South Africa's flourishing domestic Formula One championship ran from 1960 through to 1975. The frontrunning cars in the series were recently retired from the world championship although there was also a healthy selection of locally built or modified machines. Frontrunning drivers from the series usually contested their local World Championship Grand Prix, as well as occasional European events, although they had little success at that level.[citation needed]
+
+The DFV helped make the UK domestic Formula One championship possible between 1978 and 1980. As in South Africa a decade before, second hand cars from manufacturers like Lotus and Fittipaldi Automotive were the order of the day, although some, such as the March 781, were built specifically for the series. In 1980, the series saw South African Desiré Wilson become the only woman to win a Formula One race when she triumphed at Brands Hatch in a Wolf WR3.[52]
+
+A Formula One Grand Prix event spans a weekend. It begins with two free practice sessions on Friday (except in Monaco, where Friday practices are moved to Thursday), and one free practice on Saturday. Additional drivers (commonly known as third drivers) are allowed to run on Fridays, but only two cars may be used per team, requiring a race driver to give up his seat. A qualifying session is held after the last free practice session. This session determines the starting order for the race on Sunday.[53][54]
+
+The new rule for F1 tyres that was introduced in 2016 was that Pirelli could select three different tyres for each race, and each team could choose the tyre from those three depending on the strategies. This concept also continued in 2017 and in 2018 but with Pirelli's thicker and wider tyres that were tested extensively last year.
+
+Tyre selections are announced over a month before each event, with rules stating Pirelli must announce compounds nine weeks before a European round and 15 weeks before a long-haul event. Drivers ordinarily select 10 of the 13 sets available for a race weekend, though Pirelli's new tyres means the Italian company will force each driver to stick to the same allocations for the first five races as it learns about the new tyre.
+
+That means for the opening five races, drivers will have seven of the softest compound, four of the middle compound and two of the hardest compound available. Pirelli has backup compounds for introduction later in the season, if its initial batch proves to be too conservative in terms of performance or leads to greater levels of degradation than expected.[55]
+
+For much of the sport's history, qualifying sessions differed little from practice sessions; drivers would have one or more sessions in which to set their fastest time, with the grid order determined by each driver's best single lap, with the fastest on pole position. Grids were generally limited to 26 cars – if the race had more entries, qualification would also decide which drivers would start the race. During the early 1990s, the number of entries was so high that the worst-performing teams had to enter a pre-qualifying session, with the fastest cars allowed through to the main qualifying session. The qualifying format began to change in the early 2000s, with the FIA experimenting with limiting the number of laps, determining the aggregate time over two sessions, and allowing each driver only one qualifying lap.
+
+The current qualifying system was adopted in the 2006 season. Known as "knock-out" qualifying, it is split into three periods, known as Q1, Q2, and Q3. In each period, drivers run qualifying laps to attempt to advance to the next period, with the slowest drivers being "knocked out" of qualification (but not necessarily the race) at the end of the period and their grid positions set within the rearmost five based on their best lap times. Drivers are allowed as many laps as they wish within each period. After each period, all times are reset, and only a driver's fastest lap in that period (barring infractions) counts. Any timed lap started before the end of that period may be completed, and will count toward that driver's placement. The number of cars eliminated in each period is dependent on the total number of cars entered into the championship.[56] Currently, with 20 cars, Q1 runs for 18 minutes, and eliminates the slowest five drivers. During this period, any driver whose best lap takes longer than 107% of the fastest time in Q1 will not be allowed to start the race without permission from the stewards. Otherwise, all drivers proceed to the race albeit in the worst starting positions. This rule does not affect drivers in Q2 or Q3. In Q2, the 15 remaining drivers have 15 minutes to set one of the ten fastest times and proceed to the next period. Finally, Q3 lasts 12 minutes and sees the remaining ten drivers decide the first ten grid positions. At the beginning of the 2016 Formula 1 season, the FIA introduced a new qualifying format, whereby drivers were knocked out every 90 seconds after a certain amount of time had passed in each session. The aim was to mix up grid positions for the race, but due to unpopularity the FIA reverted to the above qualifying format for the Chinese GP, after running the format for only two races.[56]
+
+Each car taking part in Q3 receives an 'extra' set of the softest available tyre. This set has to be handed in after qualifying, but drivers knocked out in Q1 or Q2 can use this set for the race. The first ten drivers, i.e. the drivers through to Q3 must start the race on the tyre which set the fastest time in Q2, unless the weather requires the use of wet-weather tyres, in which case all of the rules about the tyres won't be followed.[57][58] All of the drivers that did not participate in Q3 have free tyre choice for the start of the race. Any penalties that affect grid position are applied at the end of qualifying. Grid penalties can be applied for driving infractions in the previous or current Grand Prix, or for changing a gearbox or engine component. If a car fails scrutineering, the driver will be excluded from qualifying, but will be allowed to start the race from the back of the grid at the race steward's discretion.
+
+The race begins with a warm-up lap, after which the cars assemble on the starting grid in the order they qualified. This lap is often referred to as the formation lap, as the cars lap in formation with no overtaking (although a driver who makes a mistake may regain lost ground provided they have fallen to the back of the field). The warm-up lap allows drivers to check the condition of the track and their car, gives the tyres a chance to warm up to increase traction, and also gives the pit crews time to clear themselves and their equipment from the grid.
+
+Once all the cars have formed on the grid, after the medical car positions itself behind the pack, a light system above the track indicates the start of the race: five red lights are illuminated at intervals of one second; they are all then extinguished simultaneously after an unspecified time (typically less than 3 seconds) to signal the start of the race. The start procedure may be abandoned if a driver stalls on the grid, signalled by raising his arm. If this happens, the procedure restarts: a new formation lap begins with the offending car removed from the grid. The race may also be restarted in the event of a serious accident or dangerous conditions, with the original start voided. The race may be started from behind the Safety Car if officials feel a racing start would be excessively dangerous, such as extremely heavy rainfall. As of the 2019 season, there will always be a standing restart. If due to heavy rainfall a start behind the safety car is necessary, then after the track has dried sufficiently, drivers will form up for a standing start. There is no formation lap when races start behind the Safety Car.[59]
+
+Under normal circumstances, the winner of the race is the first driver to cross the finish line having completed a set number of laps. Race officials may end the race early (putting out a red flag) due to unsafe conditions such as extreme rainfall, and it must finish within two hours, although races are only likely to last this long in the case of extreme weather or if the safety car is deployed during the race.
+
+In the 1950s, race distances varied from 300 km (190 mi) to 600 km (370 mi). The maximum race length was reduced to 400 km (250 mi) in 1966 and 325 km (202 mi) in 1971. The race length was standardised to the current 305 km (190 mi) in 1989. However, street races like Monaco have shorter distances, to keep under the two-hour limit.
+
+Drivers may overtake one another for position over the course of the race. If a leader comes across a back marker (slower car) who has completed fewer laps, the back marker is shown a blue flag[60] telling them that they are obliged to allow the leader to overtake them. The slower car is said to be "lapped" and, once the leader finishes the race, is classified as finishing the race "one lap down". A driver can be lapped numerous times, by any car in front of them. A driver who fails to finish a race, through mechanical problems, accident, or any other reason is said to have retired from the race and is "Not Classified" in the results. However, if the driver has completed more than 90% of the race distance, s/he will be classified.
+
+Throughout the race, drivers may make pit stops to change tyres and repair damage (from 1994 to 2009 inclusive, they could also refuel). Different teams and drivers employ different pit stop strategies in order to maximise their car's potential. Three dry tyre compounds, with different durability and adhesion characteristics, are available to drivers. Over the course of a race, drivers must use two of the three available compounds. The different compounds have different levels of performance, and choosing when to use which compound is a key tactical decision to make. Different tyres have different colours on their sidewalls; this allows spectators to understand the strategies. Under wet conditions, drivers may switch to one of two specialised wet weather tyres with additional grooves (one "intermediate", for mild wet conditions, such as after recent rain, one "full wet", for racing in or immediately after rain). A driver must make at least one stop to use two tyre compounds; up to three stops are typically made, although further stops may be necessary to fix damage or if weather conditions change. If rain tyres are used, drivers are no longer obliged to use both types of dry tyres.
+
+(Safety Car)
+
+(Virtual Safety Car)
+
+The format of the race has changed little through Formula One's history. The main changes have revolved around what is allowed at pit stops. In the early days of Grand Prix racing, a driver would be allowed to continue a race in his teammate's car should his develop a problem—in the modern era, cars are so carefully fitted to drivers that this has become impossible. In recent years, the emphasis has been on changing refuelling and tyre change regulations. Since the 2010 season, refuelling—which was reintroduced in 1994—has not been allowed, to encourage less tactical racing following safety concerns. The rule requiring both compounds of tyre to be used during the race was introduced in 2007, again to encourage racing on the track. The safety car is another relatively recent innovation that reduced the need to deploy the red flag, allowing races to be completed on time for a growing international live television audience.
+
+*A driver must finish within the top ten to receive a point for setting the fastest lap of the race. In the event that the driver who set the fastest lap finishes outside of the top ten then the point for fastest lap will not be awarded for that race.[64]
+
+Various systems for awarding championship points have been used since 1950. The current system, in place since 2010, awards the top ten cars points in the Drivers' and Constructors' Championships, with the winner receiving 25 points. If both cars of a team finish in the points, they both receive Constructors' Championship points. All points won at each race are added up, and the driver and constructor with the most points at the end of the season are crowned World Champions. Regardless of whether a driver stays with the same team throughout the season, or switches teams, all points earned by him count for the Drivers' Championship.[65]
+
+A driver must be classified to receive points. To be classified, a driver need not finish the race, but complete at least 90% of the winner's race distance. Therefore, it is possible for a driver to receive points even if they retired before the end of the race.[66]
+
+In the event that less than 75% of the race laps are completed by the winner, only half of the points listed in the table are awarded to the drivers and constructors. This has happened on only five occasions in the history of the championship, and it had a notable influence on the final standing of the 1984 season. The last occurrence was at the 2009 Malaysian Grand Prix when the race was called off after 31 laps due to torrential rain.[67]
+
+Since 1981,[68] Formula One teams have been required to build the chassis in which they compete, and consequently the terms "team" and "constructor" became more or less interchangeable. This requirement distinguishes the sport from series such as the IndyCar Series which allows teams to purchase chassis, and "spec series" such as GP2, which require all cars be kept to an identical specification. It also effectively prohibits privateers, which were common even in Formula One well into the 1970s.
+
+The sport's debut season, 1950, saw eighteen teams compete, but due to high costs many dropped out quickly. In fact, such was the scarcity of competitive cars for much of the first decade of Formula One that Formula Two cars were admitted to fill the grids.  Ferrari is the oldest Formula One team, the only still-active team which competed in 1950.
+
+Early manufacturer involvement came in the form of a "factory team" or "works team" (that is, one owned and staffed by a major car company), such as those of Alfa Romeo, Ferrari, or Renault. After having virtually disappeared by the early 1980s, factory teams made a comeback in the 1990s and 2000s and formed up to half the grid with Ferrari, Jaguar, BMW, Renault, Toyota, and Honda either setting up their own teams or buying out existing ones.  Mercedes-Benz owned 40% of the McLaren team and manufactured the team's engines. Factory teams make up the top competitive teams; in 2008 wholly owned factory teams took four of the top five positions in the Constructors' Championship, and McLaren the other. Ferrari holds the record for having won the most Constructors' Championships (sixteen). However, by the end of the 2000s factory teams were once again on the decline with only Ferrari, Mercedes-Benz and Renault lodging entries to the 2010 championship.
+
+Companies such as Climax, Repco, Cosworth, Hart, Judd and Supertec, which had no direct team affiliation, often sold engines to teams that could not afford to manufacture them. In the early years, independently owned Formula One teams sometimes also built their engines, though this became less common with the increased involvement of major car manufacturers such as BMW, Ferrari, Honda, Mercedes-Benz, Renault, and Toyota, whose large budgets rendered privately built engines less competitive. Cosworth was the last independent engine supplier.  Beginning in 2007, the manufacturers' deep pockets and engineering ability took over, eliminating the last of the independent engine manufacturers.[69] It is estimated the major teams spend between €100 and €200 million ($125–$225 million) per year per manufacturer on engines alone.[70]
+
+In the 2007 season, for the first time since the 1981 rule, two teams used chassis built by other teams. Super Aguri started the season using a modified Honda Racing RA106 chassis (used by Honda the previous year), while Scuderia Toro Rosso used the same chassis used by the parent Red Bull Racing team, which was formally designed by a separate subsidiary. The usage of these loopholes was ended for 2010 with the publication of new technical regulations, which require each constructor to own the intellectual property rights to their chassis,[71] which prevents a team using a chassis owned by another Formula One constructor.[72] The regulations continue to allow a team to subcontract the design and construction of the chassis to a third-party, an option used by the HRT team in 2010 and Haas currently.
+
+Although teams rarely disclose information about their budgets, it is estimated they range from US$66 million to US$400 million each.[73]
+
+Entering a new team in the Formula One World Championship requires a £25 million (about US$32 million) up-front payment to the FIA, which is then repaid to the team over the course of the season. As a consequence, constructors desiring to enter Formula One often prefer to buy an existing team: BAR's purchase of Tyrrell and Midland's purchase of Jordan allowed both of these teams to sidestep the large deposit and secure the benefits the team already had, such as TV revenue.
+
+Every team in Formula One must run two cars in every session in a Grand Prix weekend, and every team may use up to four drivers in a season.[54] A team may also run two additional drivers in Free Practice sessions,[54] which are often used to test potential new drivers for a career as a Formula One driver or gain experienced drivers to evaluate the car.[74][75] Most modern drivers are contracted for at least the duration of a season, with driver changes taking place in between seasons, in comparison to early years where drivers often competed at an ad hoc basis from race to race. Each competitor must be in the possession of a FIA Super Licence to compete in a Grand Prix,[76] which is issued to drivers who have met the criteria of success in junior motorsport categories and having achieved 300 kilometres (190 mi) of running in a Formula One car. Drivers may also be issued a Super Licence by the World Motor Sport Council if they fail to meet the criteria.[76] Although most drivers earn their seat on ability, commercial considerations also come into play with teams having to satisfy sponsors and financial demands.
+
+Teams also contract test and reserve drivers, to stand in for regular drivers when necessary and develop the team's car; although with the reduction on testing the reserve drivers' role mainly takes places on a simulator,[77] such as rFactor Pro,[78][79] which is used by most of the F1 teams.[80][81]
+
+Each driver chooses an unassigned number from 2 to 99 (excluding 17)[82] upon entering Formula One, and keeps that number during his time in the series. The number one is reserved for the reigning Drivers' Champion, who retains his previous number and may choose to (but doesn't have to) use it instead of the number one.[83] At the onset of the championship, numbers were allocated by race organisers on an ad hoc basis from race to race, and competitors did not have a permanent number throughout the season.[84] Permanent numbers were introduced in 1973 to take effect in 1974, when teams were allocated numbers in ascending order based on the Constructors' Championship standings at the end of the 1973 season. The teams would hold those numbers from season to season with the exception of the team with the world Drivers' Champion, which would swap its numbers with the one and two of the previous champion's team. New entrants were allocated spare numbers, with the exception of the number 13 which had been unused since 1976.[85] As teams kept their numbers for long periods of time, car numbers became associated with a team, such as Ferrari's 27 and 28.[84] A different system was used from 1996 to 2013: at the start of each season, the current Drivers' Champion was designated number one, his teammate number two, and the rest of the teams assigned ascending numbers according to previous season's Constructors' Championship order.[86]
+
+A total of 33 separate drivers have won the World Drivers' Championship, with Michael Schumacher holding the record for most championships with seven, as well as holding the race wins record. Lewis Hamilton has won the next most – six championships. Jochen Rindt is the only posthumous World Champion, after his points total was not surpassed despite his fatal accident at the 1970 Italian Grand Prix, with 4 races still remaining in the season. Drivers from the United Kingdom have been the most successful in the sport, with 18 championships among 10 drivers, and 278 wins among 19 drivers.
+
+Most F1 drivers start in kart racing competitions, and then come up through traditional European single seater series like Formula Ford and Formula Renault to Formula 3, and finally the GP2 Series. GP2 started in 2005, replacing Formula 3000, which itself had replaced Formula Two as the last major stepping-stone into F1. GP2 was rebranded as the FIA Formula 2 Championship in 2017. Most champions from this level graduate into F1, but 2006 GP2 champion Lewis Hamilton became the first F2, F3000 or GP2 champion to win the Formula One driver's title in 2008.[87] Drivers are not required to have competed at this level before entering Formula One. British F3 has supplied many F1 drivers, with champions, including Nigel Mansell, Ayrton Senna and Mika Häkkinen having moved straight from that series to Formula One. More rarely a driver may be picked from an even lower level, as was the case with 2007 World Champion Kimi Räikkönen, who went straight from Formula Renault to F1, as well as Max Verstappen, who made his debut following a single season in European F3.[88]
+
+American open-wheel car racing has also contributed to the Formula One grid with mixed results. CART champions Mario Andretti and Jacques Villeneuve became F1 World Champions, while Juan Pablo Montoya won seven races in F1. Other CART (also known as ChampCar) champions, like Michael Andretti and Alessandro Zanardi won no races in F1. Other drivers have taken different paths to F1; Damon Hill raced motorbikes, and Michael Schumacher raced in sports cars, albeit after climbing through the junior single-seater ranks. Former F1 driver Paul di Resta raced in DTM until he was signed with Force India in 2011. To race, however, the driver must hold an FIA Super Licence–ensuring that the driver has the requisite skills, and will not be a danger to others. Some drivers have not had the licence when first signed to an F1 team: e.g., Räikkönen received the licence despite having only 23 car races to his credit.
+
+Most F1 drivers retire in their mid to late 30s. Some F1 drivers have left to race in the United States—Nigel Mansell and Emerson Fittipaldi duelled for the 1993 CART title, Rubens Barrichello moved to IndyCar in 2012, while Jacques Villeneuve, Juan Pablo Montoya, Nelson Piquet Jr. and Scott Speed moved to NASCAR.
+
+Some drivers have moved from F1 to racing in disciplines with fewer races during the season. The German touring car championship, the DTM, is a popular category involving ex-drivers such as two-time champion Mika Häkkinen and F1 race winners Jean Alesi, David Coulthard and Ralf Schumacher. In recent years, it has become common for former F1 drivers to take up factory seats driving LMP1 cars in the FIA World Endurance Championship, with notable drivers including Mark Webber, Allan McNish, Anthony Davidson, Alexander Wurz, Kazuki Nakajima, Sébastien Buemi and Fernando Alonso.  A series for former Formula One drivers, called Grand Prix Masters, ran briefly in 2005 and 2006.[89] Other drivers have moved to Formula E such as Nelson Piquet Jr., Sébastien Buemi, Bruno Senna, Jaime Alguersuari, Nick Heidfeld, Jarno Trulli, Jean-Éric Vergne, Felipe Massa, Stoffel Vandoorne, and more. Some drivers, such as Vitantonio Liuzzi, Narain Karthikeyan and Jos Verstappen went on to race in the A1 Grand Prix series. During its existence from 2008 to 2011, Superleague Formula attracted ex-Formula One drivers like Sébastien Bourdais, Antônio Pizzonia and Giorgio Pantano.
+
+Other former F1 drivers, like Jackie Stewart, Gerhard Berger, Alain Prost and Niki Lauda returned to F1 as team owners or managers while their former competitors have become colour commentators for TV coverage such as James Hunt (BBC), Martin Brundle (BBC, ITV and Sky), David Hobbs (NBC), Alan Jones (BBC, Nine Network and Ten Network), David Coulthard (BBC and Channel 4), Luciano Burti for Globo (Brazil), and Jean Alesi for Italian national network RAI. Others, such as Damon Hill and Jackie Stewart, take active roles in running motorsport in their own countries. Carlos Reutemann became a politician and served as governor of his native state in Argentina.
+
+The number of Grands Prix held in a season has varied over the years. The inaugural 1950 world championship season comprised only seven races, while the 2019 season contained twenty-one races. Although throughout the first decades of the world championship there were no more than eleven Grands Prix a season, a large number of non-championship Formula One events also took place. The number of Grands Prix increased to an average of sixteen/seventeen by the late 1970s; simultaneously non-championship events ended by 1983. More Grands Prix began to be held in the 2000s, and recent seasons have seen an average of 19 races. In 2016 the calendar peaked at twenty-one events, the highest number of world championship races in one season.
+
+Six of the original seven races took place in Europe; the only non-European race that counted towards the World Championship in 1950 was the Indianapolis 500, which was held to different regulations and later replaced by the United States Grand Prix. The F1 championship gradually expanded to other non-European countries. Argentina hosted the first South American Grand Prix in 1953, and Morocco hosted the first African World Championship race in 1958. Asia (Japan in 1976) and Oceania (Australia in 1985) followed, and the first race in the Middle East was held in 2004. The nineteen races of the 2014 season were spread over every populated continent except for Africa, with ten Grands Prix held outside Europe.
+
+Some of the Grands Prix, such as the oldest recognised event the French Grand Prix, pre-date the formation of the World Championship and were incorporated into the championship as Formula One races in 1950. The British and Italian Grands Prix are the only events to have been held every Formula One season; other long-running races include the Belgian, German and French Grands Prix. The Monaco Grand Prix, first held in 1929 and run continuously since 1955, is widely considered to be one of the most important and prestigious automobile races in the world.[90]
+
+Traditionally each nation has hosted a single Grand Prix, which carries the name of the country. If a single country hosts multiple Grands Prix in a year they receive different names. In European countries, the second event has often been titled the European Grand Prix, or named after a neighbouring state without a race. The United States has held six separate Grands Prix, including the Indianapolis 500, with the additional events named after the host city. Grands Prix are not always held at the same circuit each year, and may switch locations due to the suitability of the track or the financial status of the race organisers. The German Grand Prix formerly alternated between the Nürburgring and Hockenheimring circuits, and others such as the American and French races have switched venues throughout their history.
+
+All Grands Prix have traditionally been run during the day, until the inaugural Singapore Grand Prix hosted the first Formula One night race,[91] which was followed in 2009 by the day–night Abu Dhabi Grand Prix and then the Bahrain Grand Prix which converted to a night race in 2014. Along with holding races at night, other Grands Prix in Asia have had their start times adjusted to benefit the European television audience.[92]
+
+Bold denotes the Grands Prix scheduled as part of the 2020 season.
+
+Since 2008, the Formula One Group has been targeting new "destination cities" to expand its global reach, with the aim to produce races from countries that have not previously been involved in the sport.[citation needed]
+This initiative started with the 2008 Singapore Grand Prix.[citation needed]
+
+Bold denotes the Grands Prix scheduled as part of the 2020 season.
+
+Due to the COVID-19 pandemic, the 2020 Formula One World Championship calendar was forced to make major changes as the pandemic resulted in the original 22-race calendar being completely changed and many races cancelled. 
+In May 2020, it was announced that some circuits would run back-to-back races for the first time. These races would be run under a different Grand Prix title. 
+Further races are due to being announced in the future with aim to ensure there are around 15-18 races to make up the 2020 season.[105]
+
+The Eifel, Emilia Romagna, Styrian and Tuscan Grands Prix are named after the regions in which the tracks are located with the 70th Anniversary Grand Prix named in honour of the 70th Anniversary of the first Formula One World Championship race.
+
+The revived Portuguese GP is back for the first time since the 1996 Estoril race, with the Portimao circuit - built in 2008 - hosting its first Formula One event.
+
+Bold denotes the Grands Prix scheduled as part of the 2020 season.
+
+A typical circuit usually features a stretch of straight road on which the starting grid is situated. The pit lane, where the drivers stop for tyres, aerodynamic adjustments and minor repairs (such as changing the car's nose due to front wing damage) during the race, retirements from the race, and where the teams work on the cars before the race, is normally located next to the starting grid. The layout of the rest of the circuit varies widely, although in most cases the circuit runs in a clockwise direction. Those few circuits that run anticlockwise (and therefore have predominantly left-handed corners) can cause drivers neck problems due to the enormous lateral forces generated by F1 cars pulling their heads in the opposite direction to normal. A single race requires hotel rooms to accommodate at least 5,000 visitors.[106]
+
+Most of the circuits currently in use are specially constructed for competition. The current street circuits are Monaco, Melbourne, Singapore, Sochi and Baku although races in other urban locations come and go (Las Vegas and Detroit, for example) and proposals for such races are often discussed—most recently New Jersey. Several circuits have been completely laid out on public roads in the past, such as Valencia in Spain, though Monaco is the only one that remains. The glamour and history of the Monaco race are the primary reasons why the circuit is still in use, even though it does not meet the strict safety requirements imposed on other tracks. Three-time World champion Nelson Piquet famously described racing in Monaco as "like riding a bicycle around your living room".[107]
+
+Circuit design to protect the safety of drivers is becoming increasingly sophisticated, as exemplified by the new Bahrain International Circuit, added in 2004 and designed—like most of F1's new circuits—by Hermann Tilke. Several of the new circuits in F1, especially those designed by Tilke, have been criticised as lacking the "flow" of such classics as Spa-Francorchamps and Imola. His redesign of the Hockenheim circuit in Germany for example, while providing more capacity for grandstands and eliminating extremely long and dangerous straights, has been frowned upon by many who argue that part of the character of the Hockenheim circuits was the long and blinding straights into dark forest sections. These newer circuits, however, are generally agreed to meet the safety standards of modern Formula One better than the older ones.
+
+Old favourites the Österreichring (today the Red Bull Ring) and the Autódromo Hermanos Rodríguez, returned to the calendar in 2014 and 2015 respectively. The Circuit of the Americas in Austin, the Sochi Autodrom in Sochi and the Baku City Circuit in Azerbaijan have all been introduced as brand new tracks since 2012. In 2020, Circuit Zandvoort was to return to the F1 calendar as the Dutch Grand Prix, having last hosted a race in 1985, but the race was suspended due to the 2020 coronavirus pandemic.
+
+Modern Formula One cars are mid-engined, hybrid, open cockpit, open wheel single-seaters. The chassis is made largely of carbon-fibre composites, rendering it light but extremely stiff and strong. The whole car, including the driver but not fuel, weighs only 740 kg (1,630 lb) – the minimum weight set by the regulations.[108] If the construction of the car is lighter than the minimum, it can be ballasted up to add the necessary weight. The race teams take advantage of this by placing this ballast at the extreme bottom of the chassis, thereby locating the centre of gravity as low as possible in order to improve handling and weight transfer.[109]
+
+The cornering speed of Formula One cars is largely determined by the aerodynamic downforce that they generate, which pushes the car down onto the track. This is provided by "wings" mounted at the front and rear of the vehicle, and by ground effect created by low air pressure under the flat bottom of the car. The aerodynamic design of the cars is very heavily constrained to limit performance and the current generation of cars sport a large number of small winglets, "barge boards", and turning vanes designed to closely control the flow of the air over, under, and around the car.
+
+The other major factor controlling the cornering speed of the cars is the design of the tyres. From 1998 to 2008, the tyres in Formula One were not "slicks" (tyres with no tread pattern) as in most other circuit racing series. Instead, each tyre had four large circumferential grooves on its surface designed to limit the cornering speed of the cars.[110] Slick tyres returned to Formula One in the 2009 season. Suspension is double wishbone or multilink front and rear, with pushrod operated springs and dampers on the chassis – one exception being that of the 2009 specification Red Bull Racing car (RB5) which used pullrod suspension at the rear, the first car to do so since the Minardi PS01 in 2001. Ferrari used a pullrod suspension at both the front and rear in their 2012 car.[111] Both Ferrari (F138) and McLaren (MP4-28) of the 2013 season used a pullrod suspension at both the front and the rear.
+
+Carbon-carbon disc brakes are used for reduced weight and increased frictional performance. These provide a very high level of braking performance and are usually the element which provokes the greatest reaction from drivers new to the formula.
+
+Formula One cars must have four uncovered wheels, all made of the same metallic material, which must be one of two magnesium alloys specified by the FIA.[112] Magnesium alloy wheels made by forging are used to achieve maximum unsprung rotating weight reduction.[113]
+
+Starting with the 2014 Formula 1 season, the engines have changed from a 2.4-litre naturally aspirated V8 to turbocharged 1.6-litre V6 "power-units".[114] These get a significant amount of their power from electric motors. In addition they include a lot of energy recovery technology. Engines run on unleaded fuel closely resembling publicly available petrol.[115] The oil which lubricates and protects the engine from overheating is very similar in viscosity to water. The 2006 generation of engines spun up to 20,000 rpm and produced up to 580 kW (780 bhp).[116] For 2007, engines were restricted to 19,000 rpm with limited development areas allowed, following the engine specification freeze since the end of 2006.[117] For the 2009 Formula One season the engines were further restricted to 18,000 rpm.[118]
+
+A wide variety of technologies—including active suspension[119] and ground effect aerodynamics[120] —are banned under the current regulations. Despite this the current generation of cars can reach speeds in excess of 350 km/h (220 mph) at some circuits.[121] The highest straight line speed recorded during a Grand Prix was 372.6 km/h (231.5 mph), set by Juan Pablo Montoya during the 2005 Italian Grand Prix.[122] A Honda Formula One car, running with minimum downforce on a runway in the Mojave Desert achieved a top speed of 415 km/h (258 mph) in 2006. According to Honda, the car fully met the FIA Formula One regulations.[123] Even with the limitations on aerodynamics, at 160 km/h (99 mph) aerodynamically generated downforce is equal to the weight of the car, and the oft-repeated claim that Formula One cars create enough downforce to "drive on the ceiling", while possible in principle, has never been put to the test. Downforce of 2.5 times the car's weight can be achieved at full speed. The downforce means that the cars can achieve a lateral force with a magnitude of up to 3.5 times that of the force of gravity (3.5g) in cornering.[124] Consequently, the driver's head is pulled sideways with a force equivalent to the weight of 20 kg in corners. Such high lateral forces are enough to make breathing difficult and the drivers need supreme concentration and fitness to maintain their focus for the one to two hours that it takes to complete the race. A high-performance road car like the Enzo Ferrari only achieves around 1g.[125]
+
+As of 2019[update], each team may have no more than two cars available for use at any time.[126] Each driver may use no more than four engines during a championship season unless he drives for more than one team. If more engines are used, he drops ten places on the starting grid of the event at which an additional engine is used. The only exception is where the engine is provided by a manufacturer or supplier taking part in its first championship season, in which case up to five may be used by a driver.[127] Each driver may use no more than one gearbox for six consecutive events; every unscheduled gearbox change requires the driver to drop five places on the grid unless he failed to finish the previous race due to reasons beyond the team's control.[128]
+
+As of 2019[update], each driver is limited to 3 power units per season, before incurring grid penalties.
+
+Formula 1 has launched a plan to become carbon neutral by 2030. It will move to ultra-efficient logistics and travel and 100% renewably powered offices, facilities and factories and offset emissions that cannot be cut. As the first step, it would begin carbon-reduction projects immediately. By 2025, all events should become "sustainable", including eliminating single-use plastics and ensuring all waste is reused, recycled or composted.[129]
+
+In March 2007, F1 Racing published its annual estimates of spending by Formula One teams.[130] The total spending of all eleven teams in 2006 was estimated at $2.9 billion US. This was broken down as follows: Toyota $418.5 million, Ferrari $406.5 m, McLaren $402 m, Honda $380.5 m, BMW Sauber $355 m, Renault $324 m, Red Bull $252 m, Williams $195.5 m, Midland F1/Spyker-MF1 $120 m, Toro Rosso $75 m, and Super Aguri $57 million.
+
+Costs vary greatly from team to team. Honda, Toyota, McLaren-Mercedes, and Ferrari were estimated to have spent approximately $200 million on engines in 2006, Renault spent approximately $125 million and Cosworth's 2006 V8 was developed for $15 million.[131] In contrast to the 2006 season on which these figures are based, the 2007 sporting regulations banned all performance related engine development.[132]
+
+Formula One teams pay entry fees of $500,000, plus $5,000 per point scored the previous year or $6,000 per point for the winner of the Constructors' Championship.  Formula One drivers pay a FIA Super Licence fee, which in 2013 was €10,000 plus €1,000 per point.[133]
+
+There have been controversies with the way profits are shared amongst the teams. The smaller teams have complained that the profits are unevenly shared, favouring established top teams. In September 2015, Force India and Sauber officially lodged a complaint with the European Union against Formula One questioning the governance and stating that the system of dividing revenues and determining the rules is unfair and unlawful.[134]
+
+The cost of building a brand new permanent circuit can be up to hundreds of millions of dollars, while the cost of converting a public road, such as Albert Park, into a temporary circuit is much less. Permanent circuits, however, can generate revenue all year round from leasing the track for private races and other races, such as MotoGP. The Shanghai International Circuit cost over $300 million[135] and the Istanbul Park circuit cost $150 million to build.[136]
+
+A number of Formula One drivers earn the highest salary of any drivers in auto racing. The highest paid driver in 2010 was Fernando Alonso, who received $40 million in salary from Ferrari—a record for any driver.[137] The very top Formula One drivers get paid more than IndyCar or NASCAR drivers, however the earnings immediately fall off after the top three F1 drivers and the majority of NASCAR racers will make more money than their F1 counterparts.[138] Most top IndyCar drivers are paid around a tenth of their Formula One counterparts.[137]
+
+The expense of Formula One has seen the FIA and the Formula One Commission attempt to create new regulations to lower the costs for a team to compete in the sport.[139][140] Cost-saving proposals have included allowing customer cars, either by teams purchasing a car from another constructor, or the series supplying a basic chassis and engine to some teams at a low cost.[141][142] Allowing teams to share more car components such as the monocoque and safety components is also under consideration.[143] The FIA also continually researches new ways to increase safety in the sport, which includes introducing new regulations and accident procedures.
+
+In the interest of making the sport truer to its role as a World Championship, Bernie Ecclestone had initiated and organised a number of Grands Prix in new countries. Proposals to hold future races are regularly made by both new locations and countries and circuits that have previously hosted a Formula One Grand Prix. The most recent addition is the returning French Grand Prix in Le Castellet, France;[144] the next new addition will be the Vietnamese and Dutch Grand Prix in 2020.[145]
+
+Following their purchase of the commercial rights to the sport in 2017, Liberty Media announced their vision for the future of Formula One at the 2018 Bahrain Grand Prix. The proposal identified five key areas, including streamlining the governance of the sport, emphasising cost-effectiveness, maintaining the sport's relevance to road cars and encouraging new manufacturers to enter the championship whilst enabling them to be competitive.[146] Liberty cited 2021 as their target date as it coincided with the need to renew commercial agreements with the teams and the end of the seven-year cycle[original research?] of engine development that started in 2014.
+
+Formula One can be seen live or tape delayed in almost every country and territory around the world and attracts one of the largest global television audiences. The 2008 season attracted a global audience of 600 million people per race.[147] It is a massive television event; the cumulative television audience was calculated to be 54 billion for the 2001 season, broadcast to 200 territories.[148]
+
+During the early 1990s, Formula One Group created a number of trademarks, an official logo, an official TV graphics package and in 2003, an official website for the sport in an attempt to give it a corporate identity. Ecclestone experimented with a digital television package (known colloquially as Bernievision) which was launched at the 1996 German Grand Prix in co-operation with German digital television service "DF1", 30 years after the first GP colour TV broadcast, the 1967 German Grand Prix. This service offered the viewer several simultaneous feeds (such as super signal, on board, top of field, backfield, highlights, pit lane, timing) which were produced with cameras, technical equipment and staff different from those used for the conventional coverage - i.e.: the "World Feed".
+
+TV stations all take what is known as the "World Feed", either produced historically by the "host broadcaster" or by FOM (Formula One Management). The host broadcaster either had one feed for all, or two separate feeds - a feed for local viewers and a feed for international viewers. The one size fits all approach meant that there was bias to a certain team or driver during the event, which led to viewers missing out on more important action and incidents. Where the two feed approach meant that replays (for when returning from an ad break) and local bias action could be overlaid on the local feed while the international feed was left unaffected.
+
+The only station that differed from this set up was "DF1" (re-branded to "Premiere" then to "Sky Deutschland")—a German channel which offers all sessions live and interactive, with features such as the onboard and pitlane channels. This service was obtained by Bernie Ecclestone at the end of 1996 and became F1 Digital Plus, which was made more widely available around Europe until the end of 2002, when the cost of the digital interactive service was thought too much. Prices were too high for viewers, considering they could watch both the qualifying and the races on free TV.
+
+After the failure of F1 Digital Plus, "Premiere" continued providing an interactive service, however, only the onboard and pit lane (for certain events) channels were available. This interactive service was a complete failure as the host broadcaster's director failed to recognise the onboard channel during the broadcast, leaving viewers frustrated looking at title cards rather than the action. The onboard feed slowly came back to life in 2005 and in 2007 was available for the whole season when F1 went widescreen.[citation needed]
+
+Upon the commencement of its coverage for the 2009 season, the BBC introduced complementary features such as the "red button" in-car camera angles, multiple soundtracks (broadcast commentary, CBBC commentary for children, or ambient sound only) and a rolling highlights package. Different combinations of these features were available across the various digital platforms in the UK and the BBC F1 web site) prior to, during, and after the race weekend. The BBC also broadcast a post-race programme called "F1 Forum" on the digital terrestrial platforms' "red button" interactive services.
+
+On 12 January 2011 F1 announced that it would adopt the HD format for the 2011 season offering a world feed at a data rate of 42 Megabits/second (MPEG-2).[149] The BBC announced later that day that its 2011 F1 coverage would be broadcast in HD[150] which was made possible due to SIS LIVE, the provider of the BBC's F1 outside broadcast coverage, having already upgraded their technical facilities to HD as of the 2010 Belgian Grand Prix.[151]
+
+It was announced on 29 July 2011, that Sky Sports and the BBC would team up to show the races in F1 from 2012 to 2018. Sky launched a channel dedicated to F1, Sky Sports F1 which covered all races live without commercial interruption as well as live practice and qualifying sessions, along with F1 programming, including interviews, archive action and magazine shows.[152] In 2012 the BBC broadcast live coverage of half of the races in the season: China, Spain, Monaco, Europe, Britain, Belgium, Singapore, Korea, Abu Dhabi, and Brazil.[153] The BBC also showed live coverage of practice and qualifying sessions from those races.[154] For the races that the BBC did not show live, "extended highlights" of the race were available a few hours after the live broadcast.[155]
+
+BBC ended its television contract after the 2015 season, three years earlier than planned.[156] The free-to-air TV rights were picked up by Channel 4 until the end of the 2018 season.[157] Sky Sports F1 coverage remained unaffected and BBC Radio 5 Live and 5 Live Sports Extra coverage was extended until the 2021 season.[158]
+
+While Sky Sports and Channel 4 are the two major broadcasters of Formula 1, other countries show Formula One races. Many use commentary from either Sky Sports or Channel 4. Some countries, however, have commentators of their own. In most of Asia (excluding China), the two main broadcasters of Formula one include the Fox network and Star Sports (in India). In the United States, ESPN holds the official rights to broadcast the sport. In Germany, Austria and Switzerland, the two main broadcasters are RTL Germany and n-TV. In China, there are multiple channels that broadcast Formula One which include CCTV, Tencent, Guangdong TV and Shanghai TV.[159]
+
+Formula One has an extensive web following, with most major TV companies covering it. The official Formula One website has live timing charts that can be used during the race to follow the leaderboard in real time. An official application has been available for in the Apple App Store since 2009,[160] and on Google Play since 2011,[161] that shows users a real-time feed of driver positions, timing and commentary.[citation needed]
+
+Formula One Management's in-house production team produces race edits synchronised to music.[162] In March 2018, Formula One Management (FOM) announced the launch of an over-the-top (OTT) streaming platform[clarify] to be known as F1 TV.[163]
+
+Currently the terms 'Formula One race' and 'World Championship race' are effectively synonymous; since 1984, every Formula One race has counted towards the World Championship, and every World Championship race has been to Formula One regulations. But the two terms are not interchangeable.
+
+The distinction is most relevant when considering career summaries and all-time lists. For example, in the List of Formula One drivers, Clemente Biondetti is shown with a single race against his name. Biondetti actually competed in four Formula One races in 1950,[168] but only one of these counted for the World Championship. Similarly, several Indianapolis 500 winners technically won their first World Championship race, though most record books choose to ignore this and instead only record regular World Championship participants.[citation needed]
+
+In January 2020, FIA and Formula One signed the United Nations "Sports for Climate Action" framework and affirmed that they would become carbon neutral by 2030. After the signing was announced, FIA President Jean Todt said: "As an international Federation comprising 244 members in 140 countries and the leader in motor sport and mobility development, we are fully committed to global environmental protection. The signing of this UN Sports for Climate Action Framework reinforces the momentum that has been growing in our Federation for many years. Since the introduction of the hybrid power unit in F1 to the creation of the Environment and Sustainability Commission, the entire FIA community has been investing time, energy and financial resources to the benefit of environmental innovations. We aim to inspire greater awareness and best practice in sustainability motor sport standards."[169]
+
+1985–1986
+
+1987–1993
+
+1994–2017
+
+2018–present
+
+1950  G. Farina
+1951  J. M. Fangio
+1952  A. Ascari
+1953  A. Ascari
+1954  J. M. Fangio
+1955  J. M. Fangio
+1956  J. M. Fangio
+1957  J. M. Fangio
+1958  M. Hawthorn
+1959  J. Brabham
+
+1960  J. Brabham
+1961  P. Hill
+1962  G. Hill
+1963  J. Clark
+1964  J. Surtees
+1965  J. Clark
+1966  J. Brabham
+1967  D. Hulme
+1968  G. Hill
+1969  J. Stewart
+
+1970  J. Rindt
+1971  J. Stewart
+1972  E. Fittipaldi
+1973  J. Stewart
+1974  E. Fittipaldi
+1975  N. Lauda
+1976  J. Hunt
+1977  N. Lauda
+1978  M. Andretti
+1979  J. Scheckter
+
+1980  A. Jones
+1981  N. Piquet
+1982  K. Rosberg
+1983  N. Piquet
+1984  N. Lauda
+1985  A. Prost
+1986  A. Prost
+1987  N. Piquet
+1988  A. Senna
+1989  A. Prost
+
+1990  A. Senna
+1991  A. Senna
+1992  N. Mansell
+1993  A. Prost
+1994  M. Schumacher
+1995  M. Schumacher
+1996  D. Hill
+1997  J. Villeneuve
+1998  M. Häkkinen
+1999  M. Häkkinen
+
+2000  M. Schumacher
+2001  M. Schumacher
+2002  M. Schumacher
+2003  M. Schumacher
+2004  M. Schumacher
+2005  F. Alonso
+2006  F. Alonso
+2007  K. Räikkönen
+2008  L. Hamilton
+2009  J. Button
+
+2010  S. Vettel
+2011  S. Vettel
+2012  S. Vettel
+2013  S. Vettel
+2014  L. Hamilton
+2015  L. Hamilton
+2016  N. Rosberg
+2017  L. Hamilton
+2018  L. Hamilton
+2019  L. Hamilton
+
+1958  Vanwall
+1959  Cooper
+
+1960  Cooper
+1961  Ferrari
+1962  BRM
+1963  Lotus
+1964  Ferrari
+1965  Lotus
+1966  Brabham
+1967  Brabham
+1968  Lotus
+1969  Matra
+
+1970  Lotus
+1971  Tyrrell
+1972  Lotus
+1973  Lotus
+1974  McLaren
+1975  Ferrari
+1976  Ferrari
+1977  Ferrari
+1978  Lotus
+1979  Ferrari
+
+1980  Williams
+1981  Williams
+1982  Ferrari
+1983  Ferrari
+1984  McLaren
+1985  McLaren
+1986  Williams
+1987  Williams
+1988  McLaren
+1989  McLaren
+
+1990  McLaren
+1991  McLaren
+1992  Williams
+1993  Williams
+1994  Williams
+1995  Benetton
+1996  Williams
+1997  Williams
+1998  McLaren
+1999  Ferrari
+
+2000  Ferrari
+2001  Ferrari
+2002  Ferrari
+2003  Ferrari
+2004  Ferrari
+2005  Renault
+2006  Renault
+2007  Ferrari
+2008  Ferrari
+2009  Brawn
+
+2010  Red Bull
+2011  Red Bull
+2012  Red Bull
+2013  Red Bull
+2014  Mercedes
+2015  Mercedes
+2016  Mercedes
+2017  Mercedes
+2018  Mercedes
+2019  Mercedes

en/2045.html.txt

@@ -0,0 +1,167 @@
+
+
+
+
+A programming language is a formal language comprising a set of instructions that produce various kinds of output. Programming languages are used in computer programming to implement algorithms.
+
+Most programming languages consist of instructions for computers. There are programmable machines that use a set of specific instructions, rather than general programming languages. Early ones preceded the invention of the digital computer, the first probably being the automatic flute player described in the 9th century by the brothers Musa in Baghdad, during the Islamic Golden Age.[1] Since the early 1800s, programs have been used to direct the behavior of machines such as Jacquard looms, music boxes and player pianos.[2] The programs for these machines (such as a player piano's scrolls) did not produce different behavior in response to different inputs or conditions.
+
+Thousands of different programming languages have been created, and more are being created every year. Many programming languages are written in an imperative form (i.e., as a sequence of operations to perform) while other languages use the declarative form (i.e. the desired result is specified, not how to achieve it).
+
+The description of a programming language is usually split into the two components of syntax (form) and semantics (meaning). Some languages are defined by a specification document (for example, the C programming language is specified by an ISO Standard) while other languages (such as Perl) have a dominant implementation that is treated as a reference. Some languages have both, with the basic language defined by a standard and extensions taken from the dominant implementation being common.
+
+A programming language is a notation for writing programs, which are specifications of a computation or algorithm.[3] Some authors restrict the term "programming language" to those languages that can express all possible algorithms.[3][4] Traits often considered important for what constitutes a programming language include:
+
+Markup languages like XML, HTML, or troff, which define structured data, are not usually considered programming languages.[13][14][15] Programming languages may, however, share the syntax with markup languages if a computational semantics is defined. XSLT, for example, is a Turing complete language entirely using XML syntax.[16][17][18] Moreover, LaTeX, which is mostly used for structuring documents, also contains a Turing complete subset.[19][20]
+
+The term computer language is sometimes used interchangeably with programming language.[21] However, the usage of both terms varies among authors, including the exact scope of each. One usage describes programming languages as a subset of computer languages.[22] Similarly, languages used in computing that have a different goal than expressing computer programs are generically designated computer languages. For instance, markup languages are sometimes referred to as computer languages to emphasize that they are not meant to be used for programming.[23]
+
+Another usage regards programming languages as theoretical constructs for programming abstract machines, and computer languages as the subset thereof that runs on physical computers, which have finite hardware resources.[24] John C. Reynolds emphasizes that formal specification languages are just as much programming languages as are the languages intended for execution. He also argues that textual and even graphical input formats that affect the behavior of a computer are programming languages, despite the fact they are commonly not Turing-complete, and remarks that ignorance of programming language concepts is the reason for many flaws in input formats.[25]
+
+Very early computers, such as Colossus, were programmed without the help of a stored program, by modifying their circuitry or setting banks of physical controls.
+
+Slightly later, programs could be written in machine language, where the programmer writes each instruction in a numeric form the hardware can execute directly. For example, the instruction to add the value in two memory location might consist of 3 numbers: an "opcode" that selects the "add" operation, and two memory locations. The programs, in decimal or binary form, were read in from punched cards, paper tape, magnetic tape or toggled in on switches on the front panel of the computer.  Machine languages were later termed first-generation programming languages (1GL).
+
+The next step was development of so-called second-generation programming languages (2GL) or assembly languages, which were still closely tied to the instruction set architecture of the specific computer. These served to make the program much more human-readable and relieved the programmer of tedious and error-prone address calculations.
+
+The first high-level programming languages, or third-generation programming languages (3GL), were written in the 1950s. An early high-level programming language to be designed for a computer was Plankalkül, developed for the German Z3 by Konrad Zuse between 1943 and 1945. However, it was not implemented until 1998 and 2000.[26]
+
+John Mauchly's Short Code, proposed in 1949, was one of the first high-level languages ever developed for an electronic computer.[27] Unlike machine code, Short Code statements represented mathematical expressions in understandable form. However, the program had to be translated into machine code every time it ran, making the process much slower than running the equivalent machine code.
+
+At the University of Manchester, Alick Glennie developed Autocode in the early 1950s. As a programming language, it used a compiler to automatically convert the language into machine code. The first code and compiler was developed in 1952 for the Mark 1 computer at the University of Manchester and is considered to be the first compiled high-level programming language.[28][29]
+
+The second autocode was developed for the Mark 1 by R. A. Brooker in 1954 and was called the "Mark 1 Autocode". Brooker also developed an autocode for the Ferranti Mercury in the 1950s in conjunction with the University of Manchester. The version for the EDSAC 2 was devised by D. F. Hartley of University of Cambridge Mathematical Laboratory in 1961. Known as EDSAC 2 Autocode, it was a straight development from Mercury Autocode adapted for local circumstances and was noted for its object code optimisation and source-language diagnostics which were advanced for the time. A contemporary but separate thread of development, Atlas Autocode was developed for the University of Manchester Atlas 1 machine.
+
+In 1954, FORTRAN was invented at IBM by John Backus. It was the first widely used high-level general purpose programming language to have a functional implementation, as opposed to just a design on paper.[30][31] It is still a popular language for high-performance computing[32] and is used for programs that benchmark and rank the world's fastest supercomputers.[33]
+
+Another early programming language was devised by Grace Hopper in the US, called FLOW-MATIC. It was developed for the UNIVAC I at Remington Rand during the period from 1955 until 1959. Hopper found that business data processing customers were uncomfortable with mathematical notation, and in early 1955, she and her team wrote a specification for an English programming language and implemented a prototype.[34] The FLOW-MATIC compiler became publicly available in early 1958 and was substantially complete in 1959.[35] FLOW-MATIC was a major influence in the design of COBOL, since only it and its direct descendant AIMACO were in actual use at the time.[36]
+
+The increased use of high-level languages introduced a requirement for low-level programming languages or system programming languages. These languages, to varying degrees, provide facilities between assembly languages and high-level languages. They can be used to perform tasks which require direct access to hardware facilities but still provide higher-level control structures and error-checking.
+
+The period from the 1960s to the late 1970s brought the development of the major language paradigms now in use:
+
+Each of these languages spawned descendants, and most modern programming languages count at least one of them in their ancestry.
+
+The 1960s and 1970s also saw considerable debate over the merits of structured programming, and whether programming languages should be designed to support it.[39] Edsger Dijkstra, in a famous 1968 letter published in the Communications of the ACM, argued that GOTO statements should be eliminated from all "higher level" programming languages.[40]
+
+The 1980s were years of relative consolidation. C++ combined object-oriented and systems programming. The United States government standardized Ada, a systems programming language derived from Pascal and intended for use by defense contractors. In Japan and elsewhere, vast sums were spent investigating so-called "fifth-generation" languages that incorporated logic programming constructs.[41] The functional languages community moved to standardize ML and Lisp. Rather than inventing new paradigms, all of these movements elaborated upon the ideas invented in the previous decades.
+
+One important trend in language design for programming large-scale systems during the 1980s was an increased focus on the use of modules or large-scale organizational units of code. Modula-2, Ada, and ML all developed notable module systems in the 1980s, which were often wedded to generic programming constructs.[42]
+
+The rapid growth of the Internet in the mid-1990s created opportunities for new languages. Perl, originally a Unix scripting tool first released in 1987, became common in dynamic websites. Java came to be used for server-side programming, and bytecode virtual machines became popular again in commercial settings with their promise of "Write once, run anywhere" (UCSD Pascal had been popular for a time in the early 1980s). These developments were not fundamentally novel; rather, they were refinements of many existing languages and paradigms (although their syntax was often based on the C family of programming languages).
+
+Programming language evolution continues, in both industry and research. Current directions include security and reliability verification, new kinds of modularity (mixins, delegates, aspects), and database integration such as Microsoft's LINQ.
+
+Fourth-generation programming languages (4GL) are computer programming languages which aim to provide a higher level of abstraction of the internal computer hardware details than 3GLs. Fifth-generation programming languages (5GL) are programming languages based on solving problems using constraints given to the program, rather than using an algorithm written by a programmer.
+
+All programming languages have some primitive building blocks for the description of data and the processes or transformations applied to them (like the addition of two numbers or the selection of an item from a collection). These primitives are defined by syntactic and semantic rules which describe their structure and meaning respectively.
+
+A programming language's surface form is known as its syntax. Most programming languages are purely textual; they use sequences of text including words, numbers, and punctuation, much like written natural languages. On the other hand, there are some programming languages which are more graphical in nature, using visual relationships between symbols to specify a program.
+
+The syntax of a language describes the possible combinations of symbols that form a syntactically correct program. The meaning given to a combination of symbols is handled by semantics (either formal or hard-coded in a reference implementation). Since most languages are textual, this article discusses textual syntax.
+
+Programming language syntax is usually defined using a combination of regular expressions (for lexical structure) and Backus–Naur form (for grammatical structure). Below is a simple grammar, based on Lisp:
+
+This grammar specifies the following:
+
+The following are examples of well-formed token sequences in this grammar: 12345, () and (a b c232 (1)).
+
+Not all syntactically correct programs are semantically correct. Many syntactically correct programs are nonetheless ill-formed, per the language's rules; and may (depending on the language specification and the soundness of the implementation) result in an error on translation or execution. In some cases, such programs may exhibit undefined behavior. Even when a program is well-defined within a language, it may still have a meaning that is not intended by the person who wrote it.
+
+Using natural language as an example, it may not be possible to assign a meaning to a grammatically correct sentence or the sentence may be false:
+
+The following C language fragment is syntactically correct, but performs operations that are not semantically defined (the operation *p >> 4 has no meaning for a value having a complex type and p->im is not defined because the value of p is the null pointer):
+
+If the type declaration on the first line were omitted, the program would trigger an error on undefined variable "p" during compilation. However, the program would still be syntactically correct since type declarations provide only semantic information.
+
+The grammar needed to specify a programming language can be classified by its position in the Chomsky hierarchy. The syntax of most programming languages can be specified using a Type-2 grammar, i.e., they are context-free grammars.[43] Some languages, including Perl and Lisp, contain constructs that allow execution during the parsing phase. Languages that have constructs that allow the programmer to alter the behavior of the parser make syntax analysis an undecidable problem, and generally blur the distinction between parsing and execution.[44] In contrast to Lisp's macro system and Perl's BEGIN blocks, which may contain general computations, C macros are merely string replacements and do not require code execution.[45]
+
+The term semantics refers to the meaning of languages, as opposed to their form (syntax).
+
+The static semantics defines restrictions on the structure of valid texts that are hard or impossible to express in standard syntactic formalisms.[3] For compiled languages, static semantics essentially include those semantic rules that can be checked at compile time. Examples include checking that every identifier is declared before it is used (in languages that require such declarations) or that the labels on the arms of a case statement are distinct.[46] Many important restrictions of this type, like checking that identifiers are used in the appropriate context (e.g. not adding an integer to a function name), or that subroutine calls have the appropriate number and type of arguments, can be enforced by defining them as rules in a logic called a type system. Other forms of static analyses like data flow analysis may also be part of static semantics. Newer programming languages like Java and C# have definite assignment analysis, a form of data flow analysis, as part of their static semantics.
+
+Once data has been specified, the machine must be instructed to perform operations on the data. For example, the semantics may define the strategy by which expressions are evaluated to values, or the manner in which control structures conditionally execute statements. The dynamic semantics (also known as execution semantics) of a language defines how and when the various constructs of a language should produce a program behavior. There are many ways of defining execution semantics. Natural language is often used to specify the execution semantics of languages commonly used in practice. A significant amount of academic research went into formal semantics of programming languages, which allow execution semantics to be specified in a formal manner. Results from this field of research have seen limited application to programming language design and implementation outside academia.
+
+A type system defines how a programming language classifies values and expressions into types, how it can manipulate those types and how they interact. The goal of a type system is to verify and usually enforce a certain level of correctness in programs written in that language by detecting certain incorrect operations. Any decidable type system involves a trade-off: while it rejects many incorrect programs, it can also prohibit some correct, albeit unusual programs. In order to bypass this downside, a number of languages have type loopholes, usually unchecked casts that may be used by the programmer to explicitly allow a normally disallowed operation between different types. In most typed languages, the type system is used only to type check programs, but a number of languages, usually functional ones, infer types, relieving the programmer from the need to write type annotations. The formal design and study of type systems is known as type theory.
+
+A language is typed if the specification of every operation defines types of data to which the operation is applicable.[47] For example, the data represented by "this text between the quotes" is a string, and in many programming languages dividing a number by a string has no meaning and will not be executed. The invalid operation may be detected when the program is compiled ("static" type checking) and will be rejected by the compiler with a compilation error message, or it may be detected while the program is running ("dynamic" type checking), resulting in a run-time exception. Many languages allow a function called an exception handler to handle this exception and, for example, always return "-1" as the result.
+
+A special case of typed languages are the single-typed languages. These are often scripting or markup languages, such as REXX or SGML, and have only one data type[dubious  – discuss]–—most commonly character strings which are used for both symbolic and numeric data.
+
+In contrast, an untyped language, such as most assembly languages, allows any operation to be performed on any data, generally sequences of bits of various lengths.[47] High-level untyped languages include BCPL, Tcl, and some varieties of Forth.
+
+In practice, while few languages are considered typed from the type theory (verifying or rejecting all operations), most modern languages offer a degree of typing.[47] Many production languages provide means to bypass or subvert the type system, trading type-safety for finer control over the program's execution (see casting).
+
+In static typing, all expressions have their types determined prior to when the program is executed, typically at compile-time. For example, 1 and (2+2) are integer expressions; they cannot be passed to a function that expects a string, or stored in a variable that is defined to hold dates.[47]
+
+Statically typed languages can be either manifestly typed or type-inferred. In the first case, the programmer must explicitly write types at certain textual positions (for example, at variable declarations). In the second case, the compiler infers the types of expressions and declarations based on context. Most mainstream statically typed languages, such as C++, C# and Java, are manifestly typed. Complete type inference has traditionally been associated with less mainstream languages, such as Haskell and ML. However, many manifestly typed languages support partial type inference; for example, C++, Java and C# all infer types in certain limited cases.[48] Additionally, some programming languages allow for some types to be automatically converted to other types; for example, an int can be used where the program expects a float.
+
+Dynamic typing, also called latent typing, determines the type-safety of operations at run time; in other words, types are associated with run-time values rather than textual expressions.[47] As with type-inferred languages, dynamically typed languages do not require the programmer to write explicit type annotations on expressions. Among other things, this may permit a single variable to refer to values of different types at different points in the program execution. However, type errors cannot be automatically detected until a piece of code is actually executed, potentially making debugging more difficult. Lisp, Smalltalk, Perl, Python, JavaScript, and Ruby are all examples of dynamically typed languages.
+
+Weak typing allows a value of one type to be treated as another, for example treating a string as a number.[47] This can occasionally be useful, but it can also allow some kinds of program faults to go undetected at compile time and even at run time.
+
+Strong typing prevents these program faults. An attempt to perform an operation on the wrong type of value raises an error.[47] Strongly typed languages are often termed type-safe or safe.
+
+An alternative definition for "weakly typed" refers to languages, such as Perl and JavaScript, which permit a large number of implicit type conversions. In JavaScript, for example, the expression 2 * x implicitly converts x to a number, and this conversion succeeds even if x is null, undefined, an Array, or a string of letters. Such implicit conversions are often useful, but they can mask programming errors.
+Strong and static are now generally considered orthogonal concepts, but usage in the literature differs. Some use the term strongly typed to mean strongly, statically typed, or, even more confusingly, to mean simply statically typed. Thus C has been called both strongly typed and weakly, statically typed.[49][50]
+
+It may seem odd to some professional programmers that C could be "weakly, statically typed". However, notice that the use of the generic pointer, the void* pointer, does allow for casting of pointers to other pointers without needing to do an explicit cast. This is extremely similar to somehow casting an array of bytes to any kind of datatype in C without using an explicit cast, such as (int) or (char).
+
+Most programming languages have an associated core library (sometimes known as the 'standard library', especially if it is included as part of the published language standard), which is conventionally made available by all implementations of the language. Core libraries typically include definitions for commonly used algorithms, data structures, and mechanisms for input and output.
+
+The line between a language and its core library differs from language to language. In some cases, the language designers may treat the library as a separate entity from the language. However, a language's core library is often treated as part of the language by its users, and some language specifications even require that this library be made available in all implementations. Indeed, some languages are designed so that the meanings of certain syntactic constructs cannot even be described without referring to the core library. For example, in Java, a string literal is defined as an instance of the java.lang.String class; similarly, in Smalltalk, an anonymous function expression (a "block") constructs an instance of the library's BlockContext class. Conversely, Scheme contains multiple coherent subsets that suffice to construct the rest of the language as library macros, and so the language designers do not even bother to say which portions of the language must be implemented as language constructs, and which must be implemented as parts of a library.
+
+Programming languages share properties with natural languages related to their purpose as vehicles for communication, having a syntactic form separate from its semantics, and showing language families of related languages branching one from another.[51][52] But as artificial constructs, they also differ in fundamental ways from languages that have evolved through usage. A significant difference is that a programming language can be fully described and studied in its entirety, since it has a precise and finite definition.[53] By contrast, natural languages have changing meanings given by their users in different communities. While constructed languages are also artificial languages designed from the ground up with a specific purpose, they lack the precise and complete semantic definition that a programming language has.
+
+Many programming languages have been designed from scratch, altered to meet new needs, and combined with other languages. Many have eventually fallen into disuse. Although there have been attempts to design one "universal" programming language that serves all purposes, all of them have failed to be generally accepted as filling this role.[54] The need for diverse programming languages arises from the diversity of contexts in which languages are used:
+
+One common trend in the development of programming languages has been to add more ability to solve problems using a higher level of abstraction. The earliest programming languages were tied very closely to the underlying hardware of the computer. As new programming languages have developed, features have been added that let programmers express ideas that are more remote from simple translation into underlying hardware instructions. Because programmers are less tied to the complexity of the computer, their programs can do more computing with less effort from the programmer. This lets them write more functionality per time unit.[55]
+
+Natural language programming has been proposed as a way to eliminate the need for a specialized language for programming. However, this goal remains distant and its benefits are open to debate. Edsger W. Dijkstra took the position that the use of a formal language is essential to prevent the introduction of meaningless constructs, and dismissed natural language programming as "foolish".[56] Alan Perlis was similarly dismissive of the idea.[57] Hybrid approaches have been taken in Structured English and SQL.
+
+A language's designers and users must construct a number of artifacts that govern and enable the practice of programming. The most important of these artifacts are the language specification and implementation.
+
+The specification of a programming language is an artifact that the language users and the implementors can use to agree upon whether a piece of source code is a valid program in that language, and if so what its behavior shall be.
+
+A programming language specification can take several forms, including the following:
+
+An implementation of a programming language provides a way to write programs in that language and execute them on one or more configurations of hardware and software. There are, broadly, two approaches to programming language implementation: compilation and interpretation. It is generally possible to implement a language using either technique.
+
+The output of a compiler may be executed by hardware or a program called an interpreter. In some implementations that make use of the interpreter approach there is no distinct boundary between compiling and interpreting. For instance, some implementations of BASIC compile and then execute the source a line at a time.
+
+Programs that are executed directly on the hardware usually run much faster than those that are interpreted in software.[61][better source needed]
+
+One technique for improving the performance of interpreted programs is just-in-time compilation. Here the virtual machine, just before execution, translates the blocks of bytecode which are going to be used to machine code, for direct execution on the hardware.
+
+Although most of the most commonly used programming languages have fully open specifications and implementations, many programming languages exist only as proprietary programming languages with the implementation available only from a single vendor, which may claim that such a proprietary language is their intellectual property. Proprietary programming languages are commonly domain specific languages or internal scripting languages for a single product; some proprietary languages are used only internally within a vendor, while others are available to external users.
+
+Some programming languages exist on the border between proprietary and open; for example, Oracle Corporation asserts proprietary rights to some aspects of the Java programming language,[62] and Microsoft's C# programming language, which has open implementations of most parts of the system, also has Common Language Runtime (CLR) as a closed environment.[63]
+
+Many proprietary languages are widely used, in spite of their proprietary nature; examples include MATLAB, VBScript, and Wolfram Language.  Some languages may make the transition from closed to open; for example, Erlang was originally an Ericsson's internal programming language.[64]
+
+Thousands of different programming languages have been created, mainly in the computing field.[65]
+Individual software projects commonly use five programming languages or more.[66]
+
+Programming languages differ from most other forms of human expression in that they require a greater degree of precision and completeness. When using a natural language to communicate with other people, human authors and speakers can be ambiguous and make small errors, and still expect their intent to be understood. However, figuratively speaking, computers "do exactly what they are told to do", and cannot "understand" what code the programmer intended to write. The combination of the language definition, a program, and the program's inputs must fully specify the external behavior that occurs when the program is executed, within the domain of control of that program. On the other hand, ideas about an algorithm can be communicated to humans without the precision required for execution by using pseudocode, which interleaves natural language with code written in a programming language.
+
+A programming language provides a structured mechanism for defining pieces of data, and the operations or transformations that may be carried out automatically on that data. A programmer uses the abstractions present in the language to represent the concepts involved in a computation. These concepts are represented as a collection of the simplest elements available (called primitives).[67] Programming is the process by which programmers combine these primitives to compose new programs, or adapt existing ones to new uses or a changing environment.
+
+Programs for a computer might be executed in a batch process without human interaction, or a user might type commands in an interactive session of an interpreter. In this case the "commands" are simply programs, whose execution is chained together. When a language can run its commands through an interpreter (such as a Unix shell or other command-line interface), without compiling, it is called a scripting language.[68]
+
+Determining which is the most widely used programming language is difficult since the definition of usage varies by context. One language may occupy the greater number of programmer hours, a different one has more lines of code, and a third may consume the most CPU time. Some languages are very popular for particular kinds of applications. For example, COBOL is still strong in the corporate data center, often on large mainframes;[69][70] Fortran in scientific and engineering applications; Ada in aerospace, transportation, military, real-time and embedded applications; and C in embedded applications and operating systems. Other languages are regularly used to write many different kinds of applications.
+
+Various methods of measuring language popularity, each subject to a different bias over what is measured, have been proposed:
+
+Combining and averaging information from various internet sites, stackify.com reported the ten most popular programming languages as (in descending order by overall popularity): Java, C, C++, Python, C#, JavaScript, VB .NET, R, PHP, and MATLAB.[74]
+
+A dialect of a programming language or a data exchange language is a (relatively small) variation or extension of the language that does not change its intrinsic nature. With languages such as Scheme and Forth, standards may be considered insufficient, inadequate or illegitimate by implementors, so often they will deviate from the standard, making a new dialect. In other cases, a dialect is created for use in a domain-specific language, often a subset. In the Lisp world, most languages that use basic S-expression syntax and Lisp-like semantics are considered Lisp dialects, although they vary wildly, as do, say, Racket and Clojure. As it is common for one language to have several dialects, it can become quite difficult for an inexperienced programmer to find the right documentation. The BASIC programming language has many dialects.
+
+The explosion of Forth dialects led to the saying "If you've seen one Forth... you've seen one Forth."
+
+There is no overarching classification scheme for programming languages. A given programming language does not usually have a single ancestor language. Languages commonly arise by combining the elements of several predecessor languages with new ideas in circulation at the time. Ideas that originate in one language will diffuse throughout a family of related languages, and then leap suddenly across familial gaps to appear in an entirely different family.
+
+The task is further complicated by the fact that languages can be classified along multiple axes. For example, Java is both an object-oriented language (because it encourages object-oriented organization) and a concurrent language (because it contains built-in constructs for running multiple threads in parallel). Python is an object-oriented scripting language.
+
+In broad strokes, programming languages divide into programming paradigms and a classification by intended domain of use, with general-purpose programming languages distinguished from domain-specific programming languages. Traditionally, programming languages have been regarded as describing computation in terms of imperative sentences, i.e. issuing commands. These are generally called imperative programming languages. A great deal of research in programming languages has been aimed at blurring the distinction between a program as a set of instructions and a program as an assertion about the desired answer, which is the main feature of declarative programming.[75] More refined paradigms include procedural programming, object-oriented programming, functional programming, and logic programming; some languages are hybrids of paradigms or multi-paradigmatic. An assembly language is not so much a paradigm as a direct model of an underlying machine architecture. By purpose, programming languages might be considered general purpose, system programming languages, scripting languages, domain-specific languages, or concurrent/distributed languages (or a combination of these).[76] Some general purpose languages were designed largely with educational goals.[77]
+
+A programming language may also be classified by factors unrelated to programming paradigm. For instance, most programming languages use English language keywords, while a minority do not. Other languages may be classified as being deliberately esoteric or not.

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+
+A fossil (from Classical Latin: fossilis, literally "obtained by digging")[1] is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood, oil, coal, and DNA remnants. The totality of fossils is known as the fossil record.
+
+Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old.[2] The oldest fossils are around 3.48 billion years old[3][4][5] to 4.1 billion years old.[6][7] The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absolute ages of rocks and the fossils they host.
+
+There are many processes that lead to fossilization, including permineralization, casts and molds, authigenic mineralization, replacement and recrystallization, adpression, carbonization, and bioimmuration.
+
+Fossils vary in size from one-micrometre (1 µm) bacteria[8] to dinosaurs and trees, many meters long and weighing many tons. A fossil normally preserves only a portion of the deceased organism, usually that portion that was partially mineralized during life, such as the bones and teeth of vertebrates, or the chitinous or calcareous exoskeletons of invertebrates. Fossils may also consist of the marks left behind by the organism while it was alive, such as animal tracks or feces (coprolites). These types of fossil are called trace fossils or ichnofossils, as opposed to body fossils. Some fossils are biochemical and are called chemofossils or biosignatures.
+
+The process of fossilization varies according to tissue type and external conditions.
+
+Permineralization is a process of fossilization that occurs when an organism is buried. The empty spaces within an organism (spaces filled with liquid or gas during life) become filled with mineral-rich groundwater. Minerals precipitate from the groundwater, occupying the empty spaces. This process can occur in very small spaces, such as within the cell wall of a plant cell. Small scale permineralization can produce very detailed fossils. For permineralization to occur, the organism must become covered by sediment soon after death, otherwise decay commences. The degree to which the remains are decayed when covered determines the later details of the fossil. Some fossils consist only of skeletal remains or teeth; other fossils contain traces of skin, feathers or even soft tissues. This is a form of diagenesis.
+
+
+
+In some cases, the original remains of the organism completely dissolve or are otherwise destroyed. The remaining organism-shaped hole in the rock is called an external mold. If this hole is later filled with other minerals, it is a cast. An endocast, or internal mold, is formed when sediments or minerals fill the internal cavity of an organism, such as the inside of a bivalve or snail or the hollow of a skull.
+
+This is a special form of cast and mold formation. If the chemistry is right, the organism (or fragment of organism) can act as a nucleus for the precipitation of minerals such as siderite, resulting in a nodule forming around it. If this happens rapidly before significant decay to the organic tissue, very fine three-dimensional morphological detail can be preserved. Nodules from the Carboniferous Mazon Creek fossil beds of Illinois, USA, are among the best documented examples of such mineralization.
+
+Replacement occurs when the shell, bone or other tissue is replaced with another mineral. In some cases mineral replacement of the original shell occurs so gradually and at such fine scales that microstructural features are preserved despite the total loss of original material. A shell is said to be recrystallized when the original skeletal compounds are still present but in a different crystal form, as from aragonite to calcite.
+
+Compression fossils, such as those of fossil ferns, are the result of chemical reduction of the complex organic molecules composing the organism's tissues. In this case the fossil consists of original material, albeit in a geochemically altered state. This chemical change is an expression of diagenesis. Often what remains is a carbonaceous film known as a phytoleim, in which case the fossil is known as a compression. Often, however, the phytoleim is lost and all that remains is an impression of the organism in the rock—an impression fossil. In many cases, however, compressions and impressions occur together. For instance, when the rock is broken open, the phytoleim will often be attached to one part (compression), whereas the counterpart will just be an impression. For this reason, one term covers the two modes of preservation: adpression.[9]
+
+Because of their antiquity, an unexpected exception to the alteration of an organism's tissues by chemical reduction of the complex organic molecules during fossilization has been the discovery of soft tissue in dinosaur fossils, including blood vessels, and the isolation of proteins and evidence for DNA fragments.[10][11][12][13] In 2014, Mary Schweitzer and her colleagues reported the presence of iron particles (goethite-aFeO(OH)) associated with soft tissues recovered from dinosaur fossils. Based on various experiments that studied the interaction of iron in haemoglobin with blood vessel tissue they proposed that solution hypoxia coupled with iron chelation enhances the stability and preservation of soft tissue and provides the basis for an explanation for the unforeseen preservation of fossil soft tissues.[14] However, a slightly older study based on eight taxa ranging in time from the Devonian to the Jurassic found that reasonably well-preserved fibrils that probably represent collagen were preserved in all these fossils and that the quality of preservation depended mostly on the arrangement of the collagen fibers, with tight packing favoring good preservation.[15] There seemed to be no correlation between geological age and quality of preservation, within that timeframe.
+
+Fossils that are carbonized or coalified consist of the organic remains which have been reduced primarily to the chemical element carbon. Carbonized fossils consist of a thin film which forms a silhouette of the original organism, and the original organic remains were typically soft tissues. Coalified fossils consist primarily of coal, and the original organic remains were typically woody in composition.
+
+Carbonized fossil of a possible leech from the Silurian Waukesha Biota of Wisconsin.
+
+Partially coalified axis (branch) of a lycopod from the Devonian of Wisconsin.
+
+Bioimmuration occurs when a skeletal organism overgrows or otherwise subsumes another organism, preserving the latter, or an impression of it, within the skeleton.[17] Usually it is a sessile skeletal organism, such as a bryozoan or an oyster, which grows along a substrate, covering other sessile sclerobionts. Sometimes the bioimmured organism is soft-bodied and is then preserved in negative relief as a kind of external mold. There are also cases where an organism settles on top of a living skeletal organism that grows upwards, preserving the settler in its skeleton. Bioimmuration is known in the fossil record from the Ordovician[18] to the Recent.[17]
+
+Paleontology seeks to map out how life evolved across geologic time. A substantial hurdle is the difficulty of working out fossil ages. Beds that preserve fossils typically lack the radioactive elements needed for radiometric dating. This technique is our only means of giving rocks greater than about 50 million years old an absolute age, and can be accurate to within 0.5% or better.[19] Although radiometric dating requires careful laboratory work, its basic principle is simple: the rates at which various radioactive elements decay are known, and so the ratio of the radioactive element to its decay products shows how long ago the radioactive element was incorporated into the rock. Radioactive elements are common only in rocks with a volcanic origin, and so the only fossil-bearing rocks that can be dated radiometrically are volcanic ash layers, which may provide termini for the intervening sediments.[19]
+
+Consequently, palaeontologists rely on stratigraphy to date fossils. Stratigraphy is the science of deciphering the "layer-cake" that is the sedimentary record.[20] Rocks normally form relatively horizontal layers, with each layer younger than the one underneath it. If a fossil is found between two layers whose ages are known, the fossil's age is claimed to lie between the two known ages.[21] Because rock sequences are not continuous, but may be broken up by faults or periods of erosion, it is very difficult to match up rock beds that are not directly adjacent. However, fossils of species that survived for a relatively short time can be used to match isolated rocks: this technique is called biostratigraphy. For instance, the conodont Eoplacognathus pseudoplanus has a short range in the Middle Ordovician period.[22] If rocks of unknown age have traces of E. pseudoplanus, they have a mid-Ordovician age. Such index fossils must be distinctive, be globally distributed and occupy a short time range to be useful. Misleading results are produced if the index fossils are incorrectly dated.[23] Stratigraphy and biostratigraphy can in general provide only relative dating (A was before B), which is often sufficient for studying evolution. However, this is difficult for some time periods, because of the problems involved in matching rocks of the same age across continents.[23] Family-tree relationships also help to narrow down the date when lineages first appeared. For instance, if fossils of B or C date to X million years ago and the calculated "family tree" says A was an ancestor of B and C, then A must have evolved earlier.
+
+It is also possible to estimate how long ago two living clades diverged, in other words approximately how long ago their last common ancestor must have lived, by assuming that DNA mutations accumulate at a constant rate. These "molecular clocks", however, are fallible, and provide only approximate timing: for example, they are not sufficiently precise and reliable for estimating when the groups that feature in the Cambrian explosion first evolved,[24] and estimates produced by different techniques may vary by a factor of two.[25]
+
+Organisms are only rarely preserved as fossils in the best of circumstances, and only a fraction of such fossils have been discovered. This is illustrated by the fact that the number of species known through the fossil record is less than 5% of the number of known living species, suggesting that the number of species known through fossils must be far less than 1% of all the species that have ever lived.[26] Because of the specialized and rare circumstances required for a biological structure to fossilize, only a small percentage of life-forms can be expected to be represented in discoveries, and each discovery represents only a snapshot of the process of evolution. The transition itself can only be illustrated and corroborated by transitional fossils, which will never demonstrate an exact half-way point.[27]
+
+The fossil record is strongly biased toward organisms with hard-parts, leaving most groups of soft-bodied organisms with little to no role.[26] It is replete with the mollusks, the vertebrates, the echinoderms, the brachiopods and some groups of arthropods.[28]
+
+Fossil sites with exceptional preservation—sometimes including preserved soft tissues—are known as Lagerstätten—German for "storage places". These formations may have resulted from carcass burial in an anoxic environment with minimal bacteria, thus slowing decomposition. Lagerstätten span geological time from the Cambrian period to the present. Worldwide, some of the best examples of near-perfect fossilization are the Cambrian Maotianshan shales and Burgess Shale, the Devonian Hunsrück Slates, the Jurassic Solnhofen limestone, and the Carboniferous Mazon Creek localities.
+
+Stromatolites are layered accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains by biofilms of microorganisms, especially cyanobacteria.[29] Stromatolites provide some of the most ancient fossil records of life on Earth, dating back more than 3.5 billion years ago.[30]
+
+Stromatolites were much more abundant in Precambrian times. While older, Archean fossil remains are presumed to be colonies of cyanobacteria, younger (that is, Proterozoic) fossils may be primordial forms of the eukaryote chlorophytes (that is, green algae). One genus of stromatolite very common in the geologic record is Collenia. The earliest stromatolite of confirmed microbial origin dates to 2.724 billion years ago.[31]
+
+A 2009 discovery provides strong evidence of microbial stromatolites extending as far back as 3.45 billion years ago.[32][33]
+
+Stromatolites are a major constituent of the fossil record for life's first 3.5 billion years, peaking about 1.25 billion years ago.[32] They subsequently declined in abundance and diversity,[34] which by the start of the Cambrian had fallen to 20% of their peak. The most widely supported explanation is that stromatolite builders fell victims to grazing creatures (the Cambrian substrate revolution), implying that sufficiently complex organisms were common over 1 billion years ago.[35][36][37]
+
+The connection between grazer and stromatolite abundance is well documented in the younger Ordovician evolutionary radiation; stromatolite abundance also increased after the end-Ordovician and end-Permian extinctions decimated marine animals, falling back to earlier levels as marine animals recovered.[38] Fluctuations in metazoan population and diversity may not have been the only factor in the reduction in stromatolite abundance. Factors such as the chemistry of the environment may have been responsible for changes.[39]
+
+While prokaryotic cyanobacteria themselves reproduce asexually through cell division, they were instrumental in priming the environment for the evolutionary development of more complex eukaryotic organisms. Cyanobacteria (as well as extremophile Gammaproteobacteria) are thought to be largely responsible for increasing the amount of oxygen in the primeval earth's atmosphere through their continuing photosynthesis. Cyanobacteria use water, carbon dioxide and sunlight to create their food. A layer of mucus often forms over mats of cyanobacterial cells. In modern microbial mats, debris from the surrounding habitat can become trapped within the mucus, which can be cemented by the calcium carbonate to grow thin laminations of limestone. These laminations can accrete over time, resulting in the banded pattern common to stromatolites. The domal morphology of biological stromatolites is the result of the vertical growth necessary for the continued infiltration of sunlight to the organisms for photosynthesis. Layered spherical growth structures termed oncolites are similar to stromatolites and are also known from the fossil record. Thrombolites are poorly laminated or non-laminated clotted structures formed by cyanobacteria common in the fossil record and in modern sediments.[31]
+
+The Zebra River Canyon area of the Kubis platform in the deeply dissected Zaris Mountains of southwestern Namibia provides an extremely well exposed example of the thrombolite-stromatolite-metazoan reefs that developed during the Proterozoic period, the stromatolites here being better developed in updip locations under conditions of higher current velocities and greater sediment influx.[40]
+
+Index fossils (also known as guide fossils, indicator fossils or zone fossils) are fossils used to define and identify geologic periods (or faunal stages). They work on the premise that, although different sediments may look different depending on the conditions under which they were deposited, they may include the remains of the same species of fossil. The shorter the species' time range, the more precisely different sediments can be correlated, and so rapidly evolving species' fossils are particularly valuable. The best index fossils are common, easy to identify at species level and have a broad distribution—otherwise the likelihood of finding and recognizing one in the two sediments is poor.
+
+Trace fossils consist mainly of tracks and burrows, but also include coprolites (fossil feces) and marks left by feeding.[41][42] Trace fossils are particularly significant because they represent a data source that is not limited to animals with easily fossilized hard parts, and they reflect animal behaviours. Many traces date from significantly earlier than the body fossils of animals that are thought to have been capable of making them.[43] Whilst exact assignment of trace fossils to their makers is generally impossible, traces may for example provide the earliest physical evidence of the appearance of moderately complex animals (comparable to earthworms).[42]
+
+Coprolites are classified as trace fossils as opposed to body fossils, as they give evidence for the animal's behaviour (in this case, diet) rather than morphology. They were first described by William Buckland in 1829. Prior to this they were known as "fossil fir cones" and "bezoar stones." They serve a valuable purpose in paleontology because they provide direct evidence of the predation and diet of extinct organisms.[44] Coprolites may range in size from a few millimetres to over 60 centimetres.
+
+Cambrian trace fossils including Rusophycus, made by a trilobite
+
+A coprolite of a carnivorous dinosaur found in southwestern Saskatchewan
+
+Densely packed, subaerial or nearshore trackways (Climactichnites wilsoni) made by a putative, slug-like mollusk on a Cambrian tidal flat
+
+A transitional fossil is any fossilized remains of a life form that exhibits traits common to both an ancestral group and its derived descendant group.[45] This is especially important where the descendant group is sharply differentiated by gross anatomy and mode of living from the ancestral group. Because of the incompleteness of the fossil record, there is usually no way to know exactly how close a transitional fossil is to the point of divergence. These fossils serve as a reminder that taxonomic divisions are human constructs that have been imposed in hindsight on a continuum of variation.
+
+Microfossil is a descriptive term applied to fossilized plants and animals whose size is just at or below the level at which the fossil can be analyzed by the naked eye. A commonly applied cutoff point between "micro" and "macro" fossils is 1 mm. Microfossils may either be complete (or near-complete) organisms in themselves (such as the marine plankters foraminifera and coccolithophores) or component parts (such as small teeth or spores) of larger animals or plants. Microfossils are of critical importance as a reservoir of paleoclimate information, and are also commonly used by biostratigraphers to assist in the correlation of rock units.
+
+Fossil resin (colloquially called amber) is a natural polymer found in many types of strata throughout the world, even the Arctic. The oldest fossil resin dates to the Triassic, though most dates to the Cenozoic. The excretion of the resin by certain plants is thought to be an evolutionary adaptation for protection from insects and to seal wounds. Fossil resin often contains other fossils called inclusions that were captured by the sticky resin. These include bacteria, fungi, other plants, and animals. Animal inclusions are usually small invertebrates, predominantly arthropods such as insects and spiders, and only extremely rarely a vertebrate such as a small lizard. Preservation of inclusions can be exquisite, including small fragments of DNA.
+
+A derived, reworked or remanié fossil is a fossil found in rock that accumulated significantly later than when the fossilized animal or plant died.[46] Reworked fossils are created by erosion exhuming (freeing) fossils from the rock formation in which they were originally deposited and their redeposition in a younger sedimentary deposit.
+
+Fossil wood is wood that is preserved in the fossil record. Wood is usually the part of a plant that is best preserved (and most easily found). Fossil wood may or may not be petrified. The fossil wood may be the only part of the plant that has been preserved:[47] therefore such wood may get a special kind of botanical name. This will usually include "xylon" and a term indicating its presumed affinity, such as Araucarioxylon (wood of Araucaria or some related genus), Palmoxylon (wood of an indeterminate palm), or Castanoxylon (wood of an indeterminate chinkapin).[48]
+
+The term subfossil can be used to refer to remains, such as bones, nests, or defecations, whose fossilization process is not complete, either because the length of time since the animal involved was living is too short (less than 10,000 years) or because the conditions in which the remains were buried were not optimal for fossilization. Subfossils are often found in caves or other shelters where they can be preserved for thousands of years.[49] The main importance of subfossil vs. fossil remains is that the former contain organic material, which can be used for radiocarbon dating or extraction and sequencing of DNA, protein, or other biomolecules. Additionally, isotope ratios can provide much information about the ecological conditions under which extinct animals lived. Subfossils are useful for studying the evolutionary history of an environment and can be important to studies in paleoclimatology.
+
+Subfossils are often found in depositionary environments, such as lake sediments, oceanic sediments, and soils. Once deposited, physical and chemical weathering can alter the state of preservation.
+
+Chemical fossils, or chemofossils, are chemicals found in rocks and fossil fuels (petroleum, coal, and natural gas) that provide an organic signature for ancient life. Molecular fossils and isotope ratios represent two types of chemical fossils.[50] The oldest traces of life on Earth are fossils of this type, including carbon isotope anomalies found in zircons that imply the existence of life as early as 4.1 billion years ago.[6][7]
+
+It has been suggested that biominerals could be important indicators of extraterrestrial life and thus could play an important role in the search for past or present life on the planet Mars. Furthermore, organic components (biosignatures) that are often associated with biominerals are believed to play crucial roles in both pre-biotic and biotic reactions.[51]
+
+On 24 January 2014, NASA reported that current studies by the Curiosity and Opportunity rovers on Mars will now be searching for evidence of ancient life, including a biosphere based on autotrophic, chemotrophic and/or chemolithoautotrophic microorganisms, as well as ancient water, including fluvio-lacustrine environments (plains related to ancient rivers or lakes) that may have been habitable.[52][53][54][55] The search for evidence of habitability, taphonomy (related to fossils), and organic carbon on the planet Mars is now a primary NASA objective.[52][53]
+
+Pseudofossils are visual patterns in rocks that are produced by geologic processes rather than biologic processes. They can easily be mistaken for real fossils. Some pseudofossils, such as geological dendrite crystals, are formed by naturally occurring fissures in the rock that get filled up by percolating minerals. Other types of pseudofossils are kidney ore (round shapes in iron ore) and moss agates, which look like moss or plant leaves. Concretions, spherical or ovoid-shaped nodules found in some sedimentary strata, were once thought to be dinosaur eggs, and are often mistaken for fossils as well.
+
+Gathering fossils dates at least to the beginning of recorded history. The fossils themselves are referred to as the fossil record. The fossil record was one of the early sources of data underlying the study of evolution and continues to be relevant to the history of life on Earth. Paleontologists examine the fossil record to understand the process of evolution and the way particular species have evolved.
+
+Fossils have been visible and common throughout most of natural history, and so documented human interaction with them goes back as far as recorded history, or earlier.
+
+There are many examples of paleolithic stone knives in Europe, with fossil echinoderms set precisely at the hand grip, going all the way back to Homo heidelbergensis and neanderthals.[56] These ancient peoples also drilled holes through the center of those round fossil shells, apparently using them as beads for necklaces.
+
+The ancient Egyptians gathered fossils of species that resembled the bones of modern species they worshipped. The god Set was associated with the hippopotamus, therefore fossilized bones of hippo-like species were kept in that deity's temples.[57] Five-rayed fossil sea urchin shells were associated with the deity Sopdu, the Morning Star, equivalent of Venus in Roman mythology.[56]
+
+Fossils appear to have directly contributed to the mythology of many civilizations, including the ancient Greeks. Classical Greek historian Herodotos wrote of an area near Hyperborea where gryphons protected golden treasure. There was indeed gold mining in that approximate region, where beaked Protoceratops skulls were common as fossils.
+
+A later Greek scholar, Aristotle, eventually realized that fossil seashells from rocks were similar to those found on the beach, indicating the fossils were once living animals. He had previously explained them in terms of vaporous exhalations,[58] which Persian polymath Avicenna modified into the theory of petrifying fluids (succus lapidificatus). This was built upon in the 14th century by Albert of Saxony, and accepted in some form by most naturalists by the 16th century.[59]
+
+Roman naturalist Pliny the Elder wrote of "tongue stones", which he called glossopetra. These were fossil shark teeth, thought by some classical cultures to look like the tongues of people or snakes.[60] He also wrote about the horns of Ammon, which are fossil ammonites, from whence the species ultimately draws its modern name. Pliny also makes one of the earlier known references to toadstones, thought until the 18th century to be a magical cure for poison originating in the heads of toads, but which are fossil teeth from Lepidotes, a Cretaceous ray-finned fish.[61]
+
+The Plains tribes of North America are thought to have similarly associated fossils, such as the many intact pterosaur fossils naturally exposed in the region, with their own mythology of the thunderbird.[62]
+
+There is no such direct mythological connection known from prehistoric Africa, but there is considerable evidence of tribes there excavating and moving fossils to ceremonial sites, apparently treating them with some reverence.[63]
+
+In Japan, fossil shark teeth were associated with the mythical tengu, thought to be the razor-sharp claws of the creature, documented some time after the 8th century AD.[60]
+
+In medieval China, the fossil bones of ancient mammals including Homo erectus were often mistaken for "dragon bones" and used as medicine and aphrodisiacs. In addition, some of these fossil bones are collected as "art" by scholars, who left scripts on various artifacts, indicating the time they were added to a collection. One good example is the famous scholar Huang Tingjian of the South Song Dynasty during the 11th century, who kept a specific seashell fossil with his own poem engraved on it.[64] In the West fossilized sea creatures on mountainsides were seen as proof of the biblical deluge.
+
+In 1027, the Persian Avicenna explained fossils' stoniness in The Book of Healing:
+
+If what is said concerning the petrifaction of animals and plants is true, the cause of this (phenomenon) is a powerful mineralizing and petrifying virtue which arises in certain stony spots, or emanates suddenly from the earth during earthquake and subsidences, and petrifies whatever comes into contact with it. As a matter of fact, the petrifaction of the bodies of plants and animals is not more extraordinary than the transformation of waters.[65]
+
+From the 13th century to the present day, scholars pointed out that the fossil skulls of Deinotherium giganteum, found in Crete and Greece, might have been interpreted as being the skulls of the Cyclopes of Greek mythology, and are possibly the origin of that Greek myth.[66][67] Their skulls appear to have a single eye-hole in the front, just like their modern elephant cousins, though in fact it's actually the opening for their trunk.
+
+In Norse mythology, echinoderm shells (the round five-part button left over from a sea urchin) were associated with the god Thor, not only being incorporated in thunderstones, representations of Thor's hammer and subsequent hammer-shaped crosses as Christianity was adopted, but also kept in houses to garner Thor's protection.[56]
+
+These grew into the shepherd's crowns of English folklore, used for decoration and as good luck charms, placed by the doorway of homes and churches.[68] In Suffolk, a different species was used as a good-luck charm by bakers, who referred to them as fairy loaves, associating them with the similarly shaped loaves of bread they baked.[69][70]
+
+More scientific views of fossils emerged during the Renaissance. Leonardo da Vinci concurred with Aristotle's view that fossils were the remains of ancient life.[71] For example, da Vinci noticed discrepancies with the biblical flood narrative as an explanation for fossil origins:
+
+If the Deluge had carried the shells for distances of three and four hundred miles from the sea it would have carried them mixed with various other natural objects all heaped up together; but even at such distances from the sea we see the oysters all together and also the shellfish and the cuttlefish and all the other shells which congregate together, found all together dead; and the solitary shells are found apart from one another as we see them every day on the sea-shores.
+
+And we find oysters together in very large families, among which some may be seen with their shells still joined together, indicating that they were left there by the sea and that they were still living when the strait of Gibraltar was cut through. In the mountains of Parma and Piacenza multitudes of shells and corals with holes may be seen still sticking to the rocks...."[72]
+
+In 1666, Nicholas Steno examined a shark, and made the association of its teeth with the "tongue stones" of ancient Greco-Roman mythology, concluding that those were not in fact the tongues of venomous snakes, but the teeth of some long-extinct species of shark.[60]
+
+Robert Hooke (1635-1703) included micrographs of fossils in his Micrographia and was among the first to observe fossil forams. His observations on fossils, which he stated to be the petrified remains of creatures some of which no longer existed, were published posthumously in 1705.[73]
+
+William Smith (1769–1839), an English canal engineer, observed that rocks of different ages (based on the law of superposition) preserved different assemblages of fossils, and that these assemblages succeeded one another in a regular and determinable order. He observed that rocks from distant locations could be correlated based on the fossils they contained. He termed this the principle of faunal succession. This principle became one of Darwin's chief pieces of evidence that biological evolution was real.
+
+Georges Cuvier came to believe that most if not all the animal fossils he examined were remains of extinct species. This led Cuvier to become an active proponent of the geological school of thought called catastrophism. Near the end of his 1796 paper on living and fossil elephants he said:
+
+All of these facts, consistent among themselves, and not opposed by any report, seem to me to prove the existence of a world previous to ours, destroyed by some kind of catastrophe.[74]
+
+Interest in fossils, and geology more generally, expanded during the early nineteenth century.  In Britain, Mary Anning's discoveries of fossils, including the first complete ichthyosaur and a complete plesiosaurus skeleton, sparked both public and scholarly interest.[75]
+
+Early naturalists well understood the similarities and differences of living species leading Linnaeus to develop a hierarchical classification system still in use today. Darwin and his contemporaries first linked the hierarchical structure of the tree of life with the then very sparse fossil record. Darwin eloquently described a process of descent with modification, or evolution, whereby organisms either adapt to natural and changing environmental pressures, or they perish.
+
+When Darwin wrote On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, the oldest animal fossils were those from the Cambrian Period, now known to be about 540 million years old. He worried about the absence of older fossils because of the implications on the validity of his theories, but he expressed hope that such fossils would be found, noting that: "only a small portion of the world is known with accuracy." Darwin also pondered the sudden appearance of many groups (i.e. phyla) in the oldest known Cambrian fossiliferous strata.[76]
+
+Since Darwin's time, the fossil record has been extended to between 2.3 and 3.5 billion years.[77] Most of these Precambrian fossils are microscopic bacteria or microfossils. However, macroscopic fossils are now known from the late Proterozoic. The Ediacara biota (also called Vendian biota) dating from 575 million years ago collectively constitutes a richly diverse assembly of early multicellular eukaryotes.
+
+The fossil record and faunal succession form the basis of the science of biostratigraphy or determining the age of rocks based on embedded fossils. For the first 150 years of geology, biostratigraphy and superposition were the only means for determining the relative age of rocks. The geologic time scale was developed based on the relative ages of rock strata as determined by the early paleontologists and stratigraphers.
+
+Since the early years of the twentieth century, absolute dating methods, such as radiometric dating (including potassium/argon, argon/argon, uranium series, and, for very recent fossils, radiocarbon dating) have been used to verify the relative ages obtained by fossils and to provide absolute ages for many fossils. Radiometric dating has shown that the earliest known stromatolites are over 3.4 billion years old.
+
+The Virtual Fossil Museum[78]
+
+Paleontology has joined with evolutionary biology to share the interdisciplinary task of outlining the tree of life, which inevitably leads backwards in time to Precambrian microscopic life when cell structure and functions evolved. Earth's deep time in the Proterozoic and deeper still in the Archean is only "recounted by microscopic fossils and subtle chemical signals."[79] Molecular biologists, using phylogenetics, can compare protein amino acid or nucleotide sequence homology (i.e., similarity) to evaluate taxonomy and evolutionary distances among organisms, with limited statistical confidence. The study of fossils, on the other hand, can more specifically pinpoint when and in what organism a mutation first appeared. Phylogenetics and paleontology work together in the clarification of science's still dim view of the appearance of life and its evolution.[80]
+
+Niles Eldredge's study of the Phacops trilobite genus supported the hypothesis that modifications to the arrangement of the trilobite's eye lenses proceeded by fits and starts over millions of years during the Devonian.[81] Eldredge's interpretation of the Phacops fossil record was that the aftermaths of the lens changes, but not the rapidly occurring evolutionary process, were fossilized. This and other data led Stephen Jay Gould and Niles Eldredge to publish their seminal paper on punctuated equilibrium in 1971.
+
+Synchrotron X-ray tomographic analysis of early Cambrian bilaterian embryonic microfossils yielded new insights of metazoan evolution at its earliest stages. The tomography technique provides previously unattainable three-dimensional resolution at the limits of fossilization. Fossils of two enigmatic bilaterians, the worm-like Markuelia and a putative, primitive protostome, Pseudooides, provide a peek at germ layer embryonic development. These 543-million-year-old embryos support the emergence of some aspects of arthropod development earlier than previously thought in the late Proterozoic. The preserved embryos from China and Siberia underwent rapid diagenetic phosphatization resulting in exquisite preservation, including cell structures. This research is a notable example of how knowledge encoded by the fossil record continues to contribute otherwise unattainable information on the emergence and development of life on Earth. For example, the research suggests Markuelia has closest affinity to priapulid worms, and is adjacent to the evolutionary branching of Priapulida, Nematoda and Arthropoda.[82]
+
+Fossil trading is the practice of buying and selling fossils. This is many times done illegally with artifacts stolen from research sites, costing many important scientific specimens each year.[83] The problem is quite pronounced in China, where many specimens have been stolen.[84]
+
+Fossil collecting (sometimes, in a non-scientific sense, fossil hunting) is the collection of fossils for scientific study, hobby, or profit. Fossil collecting, as practiced by amateurs, is the predecessor of modern paleontology and many still collect fossils and study fossils as amateurs. Professionals and amateurs alike collect fossils for their scientific value.
+
+These is some medicinal and preventive use for some fossils. Largely the use of fossils as medicine is a matter of placebo effect. However, the consumption of certain fossils has been proven to help against stomach acidity and mineral depletion. The use of fossils to address health issues is rooted in traditional medicine and include the use of fossils as talismans. The specific fossil to use to alleviate or cure an illness is often based on its resemblance of the fossils and the symptoms or affected organ.[85] The use dinosaur bones as "dragon bones" has persisted in Traditional Chinese medicine into modern times, with Mid Cretaceous dinosaur bones being used for the purpose in Ruyang County during the early 21st century.[86]
+
+Three small ammonite fossils, each approximately 1.5 cm across
+
+Eocene fossil fish Priscacara liops from the Green River Formation of Wyoming
+
+A permineralized trilobite, Asaphus kowalewskii
+
+Megalodon and Carcharodontosaurus teeth. The latter was found in the Sahara Desert.
+
+Fossil shrimp (Cretaceous)
+
+Petrified wood in Petrified Forest National Park, Arizona
+
+Petrified cone of Araucaria mirabilis from Patagonia, Argentina dating from the Jurassic Period (approx. 210 Ma)
+
+A fossil gastropod from the Pliocene of Cyprus. A serpulid worm is attached.
+
+Silurian Orthoceras fossil
+
+Eocene fossil flower from Florissant, Colorado
+
+Micraster echinoid fossil from England
+
+Productid brachiopod ventral valve; Roadian, Guadalupian (Middle Permian); Glass Mountains, Texas.
+
+Agatized coral from the Hawthorn Group (Oligocene–Miocene), Florida. An example of preservation by replacement.
+
+Fossils from beaches of the Baltic Sea island of Gotland, placed on paper with 7 mm (0.28 inch) squares
+
+Dinosaur footprints from Torotoro National Park in Bolivia.

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+
+A fossil (from Classical Latin: fossilis, literally "obtained by digging")[1] is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood, oil, coal, and DNA remnants. The totality of fossils is known as the fossil record.
+
+Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old.[2] The oldest fossils are around 3.48 billion years old[3][4][5] to 4.1 billion years old.[6][7] The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absolute ages of rocks and the fossils they host.
+
+There are many processes that lead to fossilization, including permineralization, casts and molds, authigenic mineralization, replacement and recrystallization, adpression, carbonization, and bioimmuration.
+
+Fossils vary in size from one-micrometre (1 µm) bacteria[8] to dinosaurs and trees, many meters long and weighing many tons. A fossil normally preserves only a portion of the deceased organism, usually that portion that was partially mineralized during life, such as the bones and teeth of vertebrates, or the chitinous or calcareous exoskeletons of invertebrates. Fossils may also consist of the marks left behind by the organism while it was alive, such as animal tracks or feces (coprolites). These types of fossil are called trace fossils or ichnofossils, as opposed to body fossils. Some fossils are biochemical and are called chemofossils or biosignatures.
+
+The process of fossilization varies according to tissue type and external conditions.
+
+Permineralization is a process of fossilization that occurs when an organism is buried. The empty spaces within an organism (spaces filled with liquid or gas during life) become filled with mineral-rich groundwater. Minerals precipitate from the groundwater, occupying the empty spaces. This process can occur in very small spaces, such as within the cell wall of a plant cell. Small scale permineralization can produce very detailed fossils. For permineralization to occur, the organism must become covered by sediment soon after death, otherwise decay commences. The degree to which the remains are decayed when covered determines the later details of the fossil. Some fossils consist only of skeletal remains or teeth; other fossils contain traces of skin, feathers or even soft tissues. This is a form of diagenesis.
+
+
+
+In some cases, the original remains of the organism completely dissolve or are otherwise destroyed. The remaining organism-shaped hole in the rock is called an external mold. If this hole is later filled with other minerals, it is a cast. An endocast, or internal mold, is formed when sediments or minerals fill the internal cavity of an organism, such as the inside of a bivalve or snail or the hollow of a skull.
+
+This is a special form of cast and mold formation. If the chemistry is right, the organism (or fragment of organism) can act as a nucleus for the precipitation of minerals such as siderite, resulting in a nodule forming around it. If this happens rapidly before significant decay to the organic tissue, very fine three-dimensional morphological detail can be preserved. Nodules from the Carboniferous Mazon Creek fossil beds of Illinois, USA, are among the best documented examples of such mineralization.
+
+Replacement occurs when the shell, bone or other tissue is replaced with another mineral. In some cases mineral replacement of the original shell occurs so gradually and at such fine scales that microstructural features are preserved despite the total loss of original material. A shell is said to be recrystallized when the original skeletal compounds are still present but in a different crystal form, as from aragonite to calcite.
+
+Compression fossils, such as those of fossil ferns, are the result of chemical reduction of the complex organic molecules composing the organism's tissues. In this case the fossil consists of original material, albeit in a geochemically altered state. This chemical change is an expression of diagenesis. Often what remains is a carbonaceous film known as a phytoleim, in which case the fossil is known as a compression. Often, however, the phytoleim is lost and all that remains is an impression of the organism in the rock—an impression fossil. In many cases, however, compressions and impressions occur together. For instance, when the rock is broken open, the phytoleim will often be attached to one part (compression), whereas the counterpart will just be an impression. For this reason, one term covers the two modes of preservation: adpression.[9]
+
+Because of their antiquity, an unexpected exception to the alteration of an organism's tissues by chemical reduction of the complex organic molecules during fossilization has been the discovery of soft tissue in dinosaur fossils, including blood vessels, and the isolation of proteins and evidence for DNA fragments.[10][11][12][13] In 2014, Mary Schweitzer and her colleagues reported the presence of iron particles (goethite-aFeO(OH)) associated with soft tissues recovered from dinosaur fossils. Based on various experiments that studied the interaction of iron in haemoglobin with blood vessel tissue they proposed that solution hypoxia coupled with iron chelation enhances the stability and preservation of soft tissue and provides the basis for an explanation for the unforeseen preservation of fossil soft tissues.[14] However, a slightly older study based on eight taxa ranging in time from the Devonian to the Jurassic found that reasonably well-preserved fibrils that probably represent collagen were preserved in all these fossils and that the quality of preservation depended mostly on the arrangement of the collagen fibers, with tight packing favoring good preservation.[15] There seemed to be no correlation between geological age and quality of preservation, within that timeframe.
+
+Fossils that are carbonized or coalified consist of the organic remains which have been reduced primarily to the chemical element carbon. Carbonized fossils consist of a thin film which forms a silhouette of the original organism, and the original organic remains were typically soft tissues. Coalified fossils consist primarily of coal, and the original organic remains were typically woody in composition.
+
+Carbonized fossil of a possible leech from the Silurian Waukesha Biota of Wisconsin.
+
+Partially coalified axis (branch) of a lycopod from the Devonian of Wisconsin.
+
+Bioimmuration occurs when a skeletal organism overgrows or otherwise subsumes another organism, preserving the latter, or an impression of it, within the skeleton.[17] Usually it is a sessile skeletal organism, such as a bryozoan or an oyster, which grows along a substrate, covering other sessile sclerobionts. Sometimes the bioimmured organism is soft-bodied and is then preserved in negative relief as a kind of external mold. There are also cases where an organism settles on top of a living skeletal organism that grows upwards, preserving the settler in its skeleton. Bioimmuration is known in the fossil record from the Ordovician[18] to the Recent.[17]
+
+Paleontology seeks to map out how life evolved across geologic time. A substantial hurdle is the difficulty of working out fossil ages. Beds that preserve fossils typically lack the radioactive elements needed for radiometric dating. This technique is our only means of giving rocks greater than about 50 million years old an absolute age, and can be accurate to within 0.5% or better.[19] Although radiometric dating requires careful laboratory work, its basic principle is simple: the rates at which various radioactive elements decay are known, and so the ratio of the radioactive element to its decay products shows how long ago the radioactive element was incorporated into the rock. Radioactive elements are common only in rocks with a volcanic origin, and so the only fossil-bearing rocks that can be dated radiometrically are volcanic ash layers, which may provide termini for the intervening sediments.[19]
+
+Consequently, palaeontologists rely on stratigraphy to date fossils. Stratigraphy is the science of deciphering the "layer-cake" that is the sedimentary record.[20] Rocks normally form relatively horizontal layers, with each layer younger than the one underneath it. If a fossil is found between two layers whose ages are known, the fossil's age is claimed to lie between the two known ages.[21] Because rock sequences are not continuous, but may be broken up by faults or periods of erosion, it is very difficult to match up rock beds that are not directly adjacent. However, fossils of species that survived for a relatively short time can be used to match isolated rocks: this technique is called biostratigraphy. For instance, the conodont Eoplacognathus pseudoplanus has a short range in the Middle Ordovician period.[22] If rocks of unknown age have traces of E. pseudoplanus, they have a mid-Ordovician age. Such index fossils must be distinctive, be globally distributed and occupy a short time range to be useful. Misleading results are produced if the index fossils are incorrectly dated.[23] Stratigraphy and biostratigraphy can in general provide only relative dating (A was before B), which is often sufficient for studying evolution. However, this is difficult for some time periods, because of the problems involved in matching rocks of the same age across continents.[23] Family-tree relationships also help to narrow down the date when lineages first appeared. For instance, if fossils of B or C date to X million years ago and the calculated "family tree" says A was an ancestor of B and C, then A must have evolved earlier.
+
+It is also possible to estimate how long ago two living clades diverged, in other words approximately how long ago their last common ancestor must have lived, by assuming that DNA mutations accumulate at a constant rate. These "molecular clocks", however, are fallible, and provide only approximate timing: for example, they are not sufficiently precise and reliable for estimating when the groups that feature in the Cambrian explosion first evolved,[24] and estimates produced by different techniques may vary by a factor of two.[25]
+
+Organisms are only rarely preserved as fossils in the best of circumstances, and only a fraction of such fossils have been discovered. This is illustrated by the fact that the number of species known through the fossil record is less than 5% of the number of known living species, suggesting that the number of species known through fossils must be far less than 1% of all the species that have ever lived.[26] Because of the specialized and rare circumstances required for a biological structure to fossilize, only a small percentage of life-forms can be expected to be represented in discoveries, and each discovery represents only a snapshot of the process of evolution. The transition itself can only be illustrated and corroborated by transitional fossils, which will never demonstrate an exact half-way point.[27]
+
+The fossil record is strongly biased toward organisms with hard-parts, leaving most groups of soft-bodied organisms with little to no role.[26] It is replete with the mollusks, the vertebrates, the echinoderms, the brachiopods and some groups of arthropods.[28]
+
+Fossil sites with exceptional preservation—sometimes including preserved soft tissues—are known as Lagerstätten—German for "storage places". These formations may have resulted from carcass burial in an anoxic environment with minimal bacteria, thus slowing decomposition. Lagerstätten span geological time from the Cambrian period to the present. Worldwide, some of the best examples of near-perfect fossilization are the Cambrian Maotianshan shales and Burgess Shale, the Devonian Hunsrück Slates, the Jurassic Solnhofen limestone, and the Carboniferous Mazon Creek localities.
+
+Stromatolites are layered accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains by biofilms of microorganisms, especially cyanobacteria.[29] Stromatolites provide some of the most ancient fossil records of life on Earth, dating back more than 3.5 billion years ago.[30]
+
+Stromatolites were much more abundant in Precambrian times. While older, Archean fossil remains are presumed to be colonies of cyanobacteria, younger (that is, Proterozoic) fossils may be primordial forms of the eukaryote chlorophytes (that is, green algae). One genus of stromatolite very common in the geologic record is Collenia. The earliest stromatolite of confirmed microbial origin dates to 2.724 billion years ago.[31]
+
+A 2009 discovery provides strong evidence of microbial stromatolites extending as far back as 3.45 billion years ago.[32][33]
+
+Stromatolites are a major constituent of the fossil record for life's first 3.5 billion years, peaking about 1.25 billion years ago.[32] They subsequently declined in abundance and diversity,[34] which by the start of the Cambrian had fallen to 20% of their peak. The most widely supported explanation is that stromatolite builders fell victims to grazing creatures (the Cambrian substrate revolution), implying that sufficiently complex organisms were common over 1 billion years ago.[35][36][37]
+
+The connection between grazer and stromatolite abundance is well documented in the younger Ordovician evolutionary radiation; stromatolite abundance also increased after the end-Ordovician and end-Permian extinctions decimated marine animals, falling back to earlier levels as marine animals recovered.[38] Fluctuations in metazoan population and diversity may not have been the only factor in the reduction in stromatolite abundance. Factors such as the chemistry of the environment may have been responsible for changes.[39]
+
+While prokaryotic cyanobacteria themselves reproduce asexually through cell division, they were instrumental in priming the environment for the evolutionary development of more complex eukaryotic organisms. Cyanobacteria (as well as extremophile Gammaproteobacteria) are thought to be largely responsible for increasing the amount of oxygen in the primeval earth's atmosphere through their continuing photosynthesis. Cyanobacteria use water, carbon dioxide and sunlight to create their food. A layer of mucus often forms over mats of cyanobacterial cells. In modern microbial mats, debris from the surrounding habitat can become trapped within the mucus, which can be cemented by the calcium carbonate to grow thin laminations of limestone. These laminations can accrete over time, resulting in the banded pattern common to stromatolites. The domal morphology of biological stromatolites is the result of the vertical growth necessary for the continued infiltration of sunlight to the organisms for photosynthesis. Layered spherical growth structures termed oncolites are similar to stromatolites and are also known from the fossil record. Thrombolites are poorly laminated or non-laminated clotted structures formed by cyanobacteria common in the fossil record and in modern sediments.[31]
+
+The Zebra River Canyon area of the Kubis platform in the deeply dissected Zaris Mountains of southwestern Namibia provides an extremely well exposed example of the thrombolite-stromatolite-metazoan reefs that developed during the Proterozoic period, the stromatolites here being better developed in updip locations under conditions of higher current velocities and greater sediment influx.[40]
+
+Index fossils (also known as guide fossils, indicator fossils or zone fossils) are fossils used to define and identify geologic periods (or faunal stages). They work on the premise that, although different sediments may look different depending on the conditions under which they were deposited, they may include the remains of the same species of fossil. The shorter the species' time range, the more precisely different sediments can be correlated, and so rapidly evolving species' fossils are particularly valuable. The best index fossils are common, easy to identify at species level and have a broad distribution—otherwise the likelihood of finding and recognizing one in the two sediments is poor.
+
+Trace fossils consist mainly of tracks and burrows, but also include coprolites (fossil feces) and marks left by feeding.[41][42] Trace fossils are particularly significant because they represent a data source that is not limited to animals with easily fossilized hard parts, and they reflect animal behaviours. Many traces date from significantly earlier than the body fossils of animals that are thought to have been capable of making them.[43] Whilst exact assignment of trace fossils to their makers is generally impossible, traces may for example provide the earliest physical evidence of the appearance of moderately complex animals (comparable to earthworms).[42]
+
+Coprolites are classified as trace fossils as opposed to body fossils, as they give evidence for the animal's behaviour (in this case, diet) rather than morphology. They were first described by William Buckland in 1829. Prior to this they were known as "fossil fir cones" and "bezoar stones." They serve a valuable purpose in paleontology because they provide direct evidence of the predation and diet of extinct organisms.[44] Coprolites may range in size from a few millimetres to over 60 centimetres.
+
+Cambrian trace fossils including Rusophycus, made by a trilobite
+
+A coprolite of a carnivorous dinosaur found in southwestern Saskatchewan
+
+Densely packed, subaerial or nearshore trackways (Climactichnites wilsoni) made by a putative, slug-like mollusk on a Cambrian tidal flat
+
+A transitional fossil is any fossilized remains of a life form that exhibits traits common to both an ancestral group and its derived descendant group.[45] This is especially important where the descendant group is sharply differentiated by gross anatomy and mode of living from the ancestral group. Because of the incompleteness of the fossil record, there is usually no way to know exactly how close a transitional fossil is to the point of divergence. These fossils serve as a reminder that taxonomic divisions are human constructs that have been imposed in hindsight on a continuum of variation.
+
+Microfossil is a descriptive term applied to fossilized plants and animals whose size is just at or below the level at which the fossil can be analyzed by the naked eye. A commonly applied cutoff point between "micro" and "macro" fossils is 1 mm. Microfossils may either be complete (or near-complete) organisms in themselves (such as the marine plankters foraminifera and coccolithophores) or component parts (such as small teeth or spores) of larger animals or plants. Microfossils are of critical importance as a reservoir of paleoclimate information, and are also commonly used by biostratigraphers to assist in the correlation of rock units.
+
+Fossil resin (colloquially called amber) is a natural polymer found in many types of strata throughout the world, even the Arctic. The oldest fossil resin dates to the Triassic, though most dates to the Cenozoic. The excretion of the resin by certain plants is thought to be an evolutionary adaptation for protection from insects and to seal wounds. Fossil resin often contains other fossils called inclusions that were captured by the sticky resin. These include bacteria, fungi, other plants, and animals. Animal inclusions are usually small invertebrates, predominantly arthropods such as insects and spiders, and only extremely rarely a vertebrate such as a small lizard. Preservation of inclusions can be exquisite, including small fragments of DNA.
+
+A derived, reworked or remanié fossil is a fossil found in rock that accumulated significantly later than when the fossilized animal or plant died.[46] Reworked fossils are created by erosion exhuming (freeing) fossils from the rock formation in which they were originally deposited and their redeposition in a younger sedimentary deposit.
+
+Fossil wood is wood that is preserved in the fossil record. Wood is usually the part of a plant that is best preserved (and most easily found). Fossil wood may or may not be petrified. The fossil wood may be the only part of the plant that has been preserved:[47] therefore such wood may get a special kind of botanical name. This will usually include "xylon" and a term indicating its presumed affinity, such as Araucarioxylon (wood of Araucaria or some related genus), Palmoxylon (wood of an indeterminate palm), or Castanoxylon (wood of an indeterminate chinkapin).[48]
+
+The term subfossil can be used to refer to remains, such as bones, nests, or defecations, whose fossilization process is not complete, either because the length of time since the animal involved was living is too short (less than 10,000 years) or because the conditions in which the remains were buried were not optimal for fossilization. Subfossils are often found in caves or other shelters where they can be preserved for thousands of years.[49] The main importance of subfossil vs. fossil remains is that the former contain organic material, which can be used for radiocarbon dating or extraction and sequencing of DNA, protein, or other biomolecules. Additionally, isotope ratios can provide much information about the ecological conditions under which extinct animals lived. Subfossils are useful for studying the evolutionary history of an environment and can be important to studies in paleoclimatology.
+
+Subfossils are often found in depositionary environments, such as lake sediments, oceanic sediments, and soils. Once deposited, physical and chemical weathering can alter the state of preservation.
+
+Chemical fossils, or chemofossils, are chemicals found in rocks and fossil fuels (petroleum, coal, and natural gas) that provide an organic signature for ancient life. Molecular fossils and isotope ratios represent two types of chemical fossils.[50] The oldest traces of life on Earth are fossils of this type, including carbon isotope anomalies found in zircons that imply the existence of life as early as 4.1 billion years ago.[6][7]
+
+It has been suggested that biominerals could be important indicators of extraterrestrial life and thus could play an important role in the search for past or present life on the planet Mars. Furthermore, organic components (biosignatures) that are often associated with biominerals are believed to play crucial roles in both pre-biotic and biotic reactions.[51]
+
+On 24 January 2014, NASA reported that current studies by the Curiosity and Opportunity rovers on Mars will now be searching for evidence of ancient life, including a biosphere based on autotrophic, chemotrophic and/or chemolithoautotrophic microorganisms, as well as ancient water, including fluvio-lacustrine environments (plains related to ancient rivers or lakes) that may have been habitable.[52][53][54][55] The search for evidence of habitability, taphonomy (related to fossils), and organic carbon on the planet Mars is now a primary NASA objective.[52][53]
+
+Pseudofossils are visual patterns in rocks that are produced by geologic processes rather than biologic processes. They can easily be mistaken for real fossils. Some pseudofossils, such as geological dendrite crystals, are formed by naturally occurring fissures in the rock that get filled up by percolating minerals. Other types of pseudofossils are kidney ore (round shapes in iron ore) and moss agates, which look like moss or plant leaves. Concretions, spherical or ovoid-shaped nodules found in some sedimentary strata, were once thought to be dinosaur eggs, and are often mistaken for fossils as well.
+
+Gathering fossils dates at least to the beginning of recorded history. The fossils themselves are referred to as the fossil record. The fossil record was one of the early sources of data underlying the study of evolution and continues to be relevant to the history of life on Earth. Paleontologists examine the fossil record to understand the process of evolution and the way particular species have evolved.
+
+Fossils have been visible and common throughout most of natural history, and so documented human interaction with them goes back as far as recorded history, or earlier.
+
+There are many examples of paleolithic stone knives in Europe, with fossil echinoderms set precisely at the hand grip, going all the way back to Homo heidelbergensis and neanderthals.[56] These ancient peoples also drilled holes through the center of those round fossil shells, apparently using them as beads for necklaces.
+
+The ancient Egyptians gathered fossils of species that resembled the bones of modern species they worshipped. The god Set was associated with the hippopotamus, therefore fossilized bones of hippo-like species were kept in that deity's temples.[57] Five-rayed fossil sea urchin shells were associated with the deity Sopdu, the Morning Star, equivalent of Venus in Roman mythology.[56]
+
+Fossils appear to have directly contributed to the mythology of many civilizations, including the ancient Greeks. Classical Greek historian Herodotos wrote of an area near Hyperborea where gryphons protected golden treasure. There was indeed gold mining in that approximate region, where beaked Protoceratops skulls were common as fossils.
+
+A later Greek scholar, Aristotle, eventually realized that fossil seashells from rocks were similar to those found on the beach, indicating the fossils were once living animals. He had previously explained them in terms of vaporous exhalations,[58] which Persian polymath Avicenna modified into the theory of petrifying fluids (succus lapidificatus). This was built upon in the 14th century by Albert of Saxony, and accepted in some form by most naturalists by the 16th century.[59]
+
+Roman naturalist Pliny the Elder wrote of "tongue stones", which he called glossopetra. These were fossil shark teeth, thought by some classical cultures to look like the tongues of people or snakes.[60] He also wrote about the horns of Ammon, which are fossil ammonites, from whence the species ultimately draws its modern name. Pliny also makes one of the earlier known references to toadstones, thought until the 18th century to be a magical cure for poison originating in the heads of toads, but which are fossil teeth from Lepidotes, a Cretaceous ray-finned fish.[61]
+
+The Plains tribes of North America are thought to have similarly associated fossils, such as the many intact pterosaur fossils naturally exposed in the region, with their own mythology of the thunderbird.[62]
+
+There is no such direct mythological connection known from prehistoric Africa, but there is considerable evidence of tribes there excavating and moving fossils to ceremonial sites, apparently treating them with some reverence.[63]
+
+In Japan, fossil shark teeth were associated with the mythical tengu, thought to be the razor-sharp claws of the creature, documented some time after the 8th century AD.[60]
+
+In medieval China, the fossil bones of ancient mammals including Homo erectus were often mistaken for "dragon bones" and used as medicine and aphrodisiacs. In addition, some of these fossil bones are collected as "art" by scholars, who left scripts on various artifacts, indicating the time they were added to a collection. One good example is the famous scholar Huang Tingjian of the South Song Dynasty during the 11th century, who kept a specific seashell fossil with his own poem engraved on it.[64] In the West fossilized sea creatures on mountainsides were seen as proof of the biblical deluge.
+
+In 1027, the Persian Avicenna explained fossils' stoniness in The Book of Healing:
+
+If what is said concerning the petrifaction of animals and plants is true, the cause of this (phenomenon) is a powerful mineralizing and petrifying virtue which arises in certain stony spots, or emanates suddenly from the earth during earthquake and subsidences, and petrifies whatever comes into contact with it. As a matter of fact, the petrifaction of the bodies of plants and animals is not more extraordinary than the transformation of waters.[65]
+
+From the 13th century to the present day, scholars pointed out that the fossil skulls of Deinotherium giganteum, found in Crete and Greece, might have been interpreted as being the skulls of the Cyclopes of Greek mythology, and are possibly the origin of that Greek myth.[66][67] Their skulls appear to have a single eye-hole in the front, just like their modern elephant cousins, though in fact it's actually the opening for their trunk.
+
+In Norse mythology, echinoderm shells (the round five-part button left over from a sea urchin) were associated with the god Thor, not only being incorporated in thunderstones, representations of Thor's hammer and subsequent hammer-shaped crosses as Christianity was adopted, but also kept in houses to garner Thor's protection.[56]
+
+These grew into the shepherd's crowns of English folklore, used for decoration and as good luck charms, placed by the doorway of homes and churches.[68] In Suffolk, a different species was used as a good-luck charm by bakers, who referred to them as fairy loaves, associating them with the similarly shaped loaves of bread they baked.[69][70]
+
+More scientific views of fossils emerged during the Renaissance. Leonardo da Vinci concurred with Aristotle's view that fossils were the remains of ancient life.[71] For example, da Vinci noticed discrepancies with the biblical flood narrative as an explanation for fossil origins:
+
+If the Deluge had carried the shells for distances of three and four hundred miles from the sea it would have carried them mixed with various other natural objects all heaped up together; but even at such distances from the sea we see the oysters all together and also the shellfish and the cuttlefish and all the other shells which congregate together, found all together dead; and the solitary shells are found apart from one another as we see them every day on the sea-shores.
+
+And we find oysters together in very large families, among which some may be seen with their shells still joined together, indicating that they were left there by the sea and that they were still living when the strait of Gibraltar was cut through. In the mountains of Parma and Piacenza multitudes of shells and corals with holes may be seen still sticking to the rocks...."[72]
+
+In 1666, Nicholas Steno examined a shark, and made the association of its teeth with the "tongue stones" of ancient Greco-Roman mythology, concluding that those were not in fact the tongues of venomous snakes, but the teeth of some long-extinct species of shark.[60]
+
+Robert Hooke (1635-1703) included micrographs of fossils in his Micrographia and was among the first to observe fossil forams. His observations on fossils, which he stated to be the petrified remains of creatures some of which no longer existed, were published posthumously in 1705.[73]
+
+William Smith (1769–1839), an English canal engineer, observed that rocks of different ages (based on the law of superposition) preserved different assemblages of fossils, and that these assemblages succeeded one another in a regular and determinable order. He observed that rocks from distant locations could be correlated based on the fossils they contained. He termed this the principle of faunal succession. This principle became one of Darwin's chief pieces of evidence that biological evolution was real.
+
+Georges Cuvier came to believe that most if not all the animal fossils he examined were remains of extinct species. This led Cuvier to become an active proponent of the geological school of thought called catastrophism. Near the end of his 1796 paper on living and fossil elephants he said:
+
+All of these facts, consistent among themselves, and not opposed by any report, seem to me to prove the existence of a world previous to ours, destroyed by some kind of catastrophe.[74]
+
+Interest in fossils, and geology more generally, expanded during the early nineteenth century.  In Britain, Mary Anning's discoveries of fossils, including the first complete ichthyosaur and a complete plesiosaurus skeleton, sparked both public and scholarly interest.[75]
+
+Early naturalists well understood the similarities and differences of living species leading Linnaeus to develop a hierarchical classification system still in use today. Darwin and his contemporaries first linked the hierarchical structure of the tree of life with the then very sparse fossil record. Darwin eloquently described a process of descent with modification, or evolution, whereby organisms either adapt to natural and changing environmental pressures, or they perish.
+
+When Darwin wrote On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, the oldest animal fossils were those from the Cambrian Period, now known to be about 540 million years old. He worried about the absence of older fossils because of the implications on the validity of his theories, but he expressed hope that such fossils would be found, noting that: "only a small portion of the world is known with accuracy." Darwin also pondered the sudden appearance of many groups (i.e. phyla) in the oldest known Cambrian fossiliferous strata.[76]
+
+Since Darwin's time, the fossil record has been extended to between 2.3 and 3.5 billion years.[77] Most of these Precambrian fossils are microscopic bacteria or microfossils. However, macroscopic fossils are now known from the late Proterozoic. The Ediacara biota (also called Vendian biota) dating from 575 million years ago collectively constitutes a richly diverse assembly of early multicellular eukaryotes.
+
+The fossil record and faunal succession form the basis of the science of biostratigraphy or determining the age of rocks based on embedded fossils. For the first 150 years of geology, biostratigraphy and superposition were the only means for determining the relative age of rocks. The geologic time scale was developed based on the relative ages of rock strata as determined by the early paleontologists and stratigraphers.
+
+Since the early years of the twentieth century, absolute dating methods, such as radiometric dating (including potassium/argon, argon/argon, uranium series, and, for very recent fossils, radiocarbon dating) have been used to verify the relative ages obtained by fossils and to provide absolute ages for many fossils. Radiometric dating has shown that the earliest known stromatolites are over 3.4 billion years old.
+
+The Virtual Fossil Museum[78]
+
+Paleontology has joined with evolutionary biology to share the interdisciplinary task of outlining the tree of life, which inevitably leads backwards in time to Precambrian microscopic life when cell structure and functions evolved. Earth's deep time in the Proterozoic and deeper still in the Archean is only "recounted by microscopic fossils and subtle chemical signals."[79] Molecular biologists, using phylogenetics, can compare protein amino acid or nucleotide sequence homology (i.e., similarity) to evaluate taxonomy and evolutionary distances among organisms, with limited statistical confidence. The study of fossils, on the other hand, can more specifically pinpoint when and in what organism a mutation first appeared. Phylogenetics and paleontology work together in the clarification of science's still dim view of the appearance of life and its evolution.[80]
+
+Niles Eldredge's study of the Phacops trilobite genus supported the hypothesis that modifications to the arrangement of the trilobite's eye lenses proceeded by fits and starts over millions of years during the Devonian.[81] Eldredge's interpretation of the Phacops fossil record was that the aftermaths of the lens changes, but not the rapidly occurring evolutionary process, were fossilized. This and other data led Stephen Jay Gould and Niles Eldredge to publish their seminal paper on punctuated equilibrium in 1971.
+
+Synchrotron X-ray tomographic analysis of early Cambrian bilaterian embryonic microfossils yielded new insights of metazoan evolution at its earliest stages. The tomography technique provides previously unattainable three-dimensional resolution at the limits of fossilization. Fossils of two enigmatic bilaterians, the worm-like Markuelia and a putative, primitive protostome, Pseudooides, provide a peek at germ layer embryonic development. These 543-million-year-old embryos support the emergence of some aspects of arthropod development earlier than previously thought in the late Proterozoic. The preserved embryos from China and Siberia underwent rapid diagenetic phosphatization resulting in exquisite preservation, including cell structures. This research is a notable example of how knowledge encoded by the fossil record continues to contribute otherwise unattainable information on the emergence and development of life on Earth. For example, the research suggests Markuelia has closest affinity to priapulid worms, and is adjacent to the evolutionary branching of Priapulida, Nematoda and Arthropoda.[82]
+
+Fossil trading is the practice of buying and selling fossils. This is many times done illegally with artifacts stolen from research sites, costing many important scientific specimens each year.[83] The problem is quite pronounced in China, where many specimens have been stolen.[84]
+
+Fossil collecting (sometimes, in a non-scientific sense, fossil hunting) is the collection of fossils for scientific study, hobby, or profit. Fossil collecting, as practiced by amateurs, is the predecessor of modern paleontology and many still collect fossils and study fossils as amateurs. Professionals and amateurs alike collect fossils for their scientific value.
+
+These is some medicinal and preventive use for some fossils. Largely the use of fossils as medicine is a matter of placebo effect. However, the consumption of certain fossils has been proven to help against stomach acidity and mineral depletion. The use of fossils to address health issues is rooted in traditional medicine and include the use of fossils as talismans. The specific fossil to use to alleviate or cure an illness is often based on its resemblance of the fossils and the symptoms or affected organ.[85] The use dinosaur bones as "dragon bones" has persisted in Traditional Chinese medicine into modern times, with Mid Cretaceous dinosaur bones being used for the purpose in Ruyang County during the early 21st century.[86]
+
+Three small ammonite fossils, each approximately 1.5 cm across
+
+Eocene fossil fish Priscacara liops from the Green River Formation of Wyoming
+
+A permineralized trilobite, Asaphus kowalewskii
+
+Megalodon and Carcharodontosaurus teeth. The latter was found in the Sahara Desert.
+
+Fossil shrimp (Cretaceous)
+
+Petrified wood in Petrified Forest National Park, Arizona
+
+Petrified cone of Araucaria mirabilis from Patagonia, Argentina dating from the Jurassic Period (approx. 210 Ma)
+
+A fossil gastropod from the Pliocene of Cyprus. A serpulid worm is attached.
+
+Silurian Orthoceras fossil
+
+Eocene fossil flower from Florissant, Colorado
+
+Micraster echinoid fossil from England
+
+Productid brachiopod ventral valve; Roadian, Guadalupian (Middle Permian); Glass Mountains, Texas.
+
+Agatized coral from the Hawthorn Group (Oligocene–Miocene), Florida. An example of preservation by replacement.
+
+Fossils from beaches of the Baltic Sea island of Gotland, placed on paper with 7 mm (0.28 inch) squares
+
+Dinosaur footprints from Torotoro National Park in Bolivia.

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+
+A fossil (from Classical Latin: fossilis, literally "obtained by digging")[1] is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood, oil, coal, and DNA remnants. The totality of fossils is known as the fossil record.
+
+Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old.[2] The oldest fossils are around 3.48 billion years old[3][4][5] to 4.1 billion years old.[6][7] The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absolute ages of rocks and the fossils they host.
+
+There are many processes that lead to fossilization, including permineralization, casts and molds, authigenic mineralization, replacement and recrystallization, adpression, carbonization, and bioimmuration.
+
+Fossils vary in size from one-micrometre (1 µm) bacteria[8] to dinosaurs and trees, many meters long and weighing many tons. A fossil normally preserves only a portion of the deceased organism, usually that portion that was partially mineralized during life, such as the bones and teeth of vertebrates, or the chitinous or calcareous exoskeletons of invertebrates. Fossils may also consist of the marks left behind by the organism while it was alive, such as animal tracks or feces (coprolites). These types of fossil are called trace fossils or ichnofossils, as opposed to body fossils. Some fossils are biochemical and are called chemofossils or biosignatures.
+
+The process of fossilization varies according to tissue type and external conditions.
+
+Permineralization is a process of fossilization that occurs when an organism is buried. The empty spaces within an organism (spaces filled with liquid or gas during life) become filled with mineral-rich groundwater. Minerals precipitate from the groundwater, occupying the empty spaces. This process can occur in very small spaces, such as within the cell wall of a plant cell. Small scale permineralization can produce very detailed fossils. For permineralization to occur, the organism must become covered by sediment soon after death, otherwise decay commences. The degree to which the remains are decayed when covered determines the later details of the fossil. Some fossils consist only of skeletal remains or teeth; other fossils contain traces of skin, feathers or even soft tissues. This is a form of diagenesis.
+
+
+
+In some cases, the original remains of the organism completely dissolve or are otherwise destroyed. The remaining organism-shaped hole in the rock is called an external mold. If this hole is later filled with other minerals, it is a cast. An endocast, or internal mold, is formed when sediments or minerals fill the internal cavity of an organism, such as the inside of a bivalve or snail or the hollow of a skull.
+
+This is a special form of cast and mold formation. If the chemistry is right, the organism (or fragment of organism) can act as a nucleus for the precipitation of minerals such as siderite, resulting in a nodule forming around it. If this happens rapidly before significant decay to the organic tissue, very fine three-dimensional morphological detail can be preserved. Nodules from the Carboniferous Mazon Creek fossil beds of Illinois, USA, are among the best documented examples of such mineralization.
+
+Replacement occurs when the shell, bone or other tissue is replaced with another mineral. In some cases mineral replacement of the original shell occurs so gradually and at such fine scales that microstructural features are preserved despite the total loss of original material. A shell is said to be recrystallized when the original skeletal compounds are still present but in a different crystal form, as from aragonite to calcite.
+
+Compression fossils, such as those of fossil ferns, are the result of chemical reduction of the complex organic molecules composing the organism's tissues. In this case the fossil consists of original material, albeit in a geochemically altered state. This chemical change is an expression of diagenesis. Often what remains is a carbonaceous film known as a phytoleim, in which case the fossil is known as a compression. Often, however, the phytoleim is lost and all that remains is an impression of the organism in the rock—an impression fossil. In many cases, however, compressions and impressions occur together. For instance, when the rock is broken open, the phytoleim will often be attached to one part (compression), whereas the counterpart will just be an impression. For this reason, one term covers the two modes of preservation: adpression.[9]
+
+Because of their antiquity, an unexpected exception to the alteration of an organism's tissues by chemical reduction of the complex organic molecules during fossilization has been the discovery of soft tissue in dinosaur fossils, including blood vessels, and the isolation of proteins and evidence for DNA fragments.[10][11][12][13] In 2014, Mary Schweitzer and her colleagues reported the presence of iron particles (goethite-aFeO(OH)) associated with soft tissues recovered from dinosaur fossils. Based on various experiments that studied the interaction of iron in haemoglobin with blood vessel tissue they proposed that solution hypoxia coupled with iron chelation enhances the stability and preservation of soft tissue and provides the basis for an explanation for the unforeseen preservation of fossil soft tissues.[14] However, a slightly older study based on eight taxa ranging in time from the Devonian to the Jurassic found that reasonably well-preserved fibrils that probably represent collagen were preserved in all these fossils and that the quality of preservation depended mostly on the arrangement of the collagen fibers, with tight packing favoring good preservation.[15] There seemed to be no correlation between geological age and quality of preservation, within that timeframe.
+
+Fossils that are carbonized or coalified consist of the organic remains which have been reduced primarily to the chemical element carbon. Carbonized fossils consist of a thin film which forms a silhouette of the original organism, and the original organic remains were typically soft tissues. Coalified fossils consist primarily of coal, and the original organic remains were typically woody in composition.
+
+Carbonized fossil of a possible leech from the Silurian Waukesha Biota of Wisconsin.
+
+Partially coalified axis (branch) of a lycopod from the Devonian of Wisconsin.
+
+Bioimmuration occurs when a skeletal organism overgrows or otherwise subsumes another organism, preserving the latter, or an impression of it, within the skeleton.[17] Usually it is a sessile skeletal organism, such as a bryozoan or an oyster, which grows along a substrate, covering other sessile sclerobionts. Sometimes the bioimmured organism is soft-bodied and is then preserved in negative relief as a kind of external mold. There are also cases where an organism settles on top of a living skeletal organism that grows upwards, preserving the settler in its skeleton. Bioimmuration is known in the fossil record from the Ordovician[18] to the Recent.[17]
+
+Paleontology seeks to map out how life evolved across geologic time. A substantial hurdle is the difficulty of working out fossil ages. Beds that preserve fossils typically lack the radioactive elements needed for radiometric dating. This technique is our only means of giving rocks greater than about 50 million years old an absolute age, and can be accurate to within 0.5% or better.[19] Although radiometric dating requires careful laboratory work, its basic principle is simple: the rates at which various radioactive elements decay are known, and so the ratio of the radioactive element to its decay products shows how long ago the radioactive element was incorporated into the rock. Radioactive elements are common only in rocks with a volcanic origin, and so the only fossil-bearing rocks that can be dated radiometrically are volcanic ash layers, which may provide termini for the intervening sediments.[19]
+
+Consequently, palaeontologists rely on stratigraphy to date fossils. Stratigraphy is the science of deciphering the "layer-cake" that is the sedimentary record.[20] Rocks normally form relatively horizontal layers, with each layer younger than the one underneath it. If a fossil is found between two layers whose ages are known, the fossil's age is claimed to lie between the two known ages.[21] Because rock sequences are not continuous, but may be broken up by faults or periods of erosion, it is very difficult to match up rock beds that are not directly adjacent. However, fossils of species that survived for a relatively short time can be used to match isolated rocks: this technique is called biostratigraphy. For instance, the conodont Eoplacognathus pseudoplanus has a short range in the Middle Ordovician period.[22] If rocks of unknown age have traces of E. pseudoplanus, they have a mid-Ordovician age. Such index fossils must be distinctive, be globally distributed and occupy a short time range to be useful. Misleading results are produced if the index fossils are incorrectly dated.[23] Stratigraphy and biostratigraphy can in general provide only relative dating (A was before B), which is often sufficient for studying evolution. However, this is difficult for some time periods, because of the problems involved in matching rocks of the same age across continents.[23] Family-tree relationships also help to narrow down the date when lineages first appeared. For instance, if fossils of B or C date to X million years ago and the calculated "family tree" says A was an ancestor of B and C, then A must have evolved earlier.
+
+It is also possible to estimate how long ago two living clades diverged, in other words approximately how long ago their last common ancestor must have lived, by assuming that DNA mutations accumulate at a constant rate. These "molecular clocks", however, are fallible, and provide only approximate timing: for example, they are not sufficiently precise and reliable for estimating when the groups that feature in the Cambrian explosion first evolved,[24] and estimates produced by different techniques may vary by a factor of two.[25]
+
+Organisms are only rarely preserved as fossils in the best of circumstances, and only a fraction of such fossils have been discovered. This is illustrated by the fact that the number of species known through the fossil record is less than 5% of the number of known living species, suggesting that the number of species known through fossils must be far less than 1% of all the species that have ever lived.[26] Because of the specialized and rare circumstances required for a biological structure to fossilize, only a small percentage of life-forms can be expected to be represented in discoveries, and each discovery represents only a snapshot of the process of evolution. The transition itself can only be illustrated and corroborated by transitional fossils, which will never demonstrate an exact half-way point.[27]
+
+The fossil record is strongly biased toward organisms with hard-parts, leaving most groups of soft-bodied organisms with little to no role.[26] It is replete with the mollusks, the vertebrates, the echinoderms, the brachiopods and some groups of arthropods.[28]
+
+Fossil sites with exceptional preservation—sometimes including preserved soft tissues—are known as Lagerstätten—German for "storage places". These formations may have resulted from carcass burial in an anoxic environment with minimal bacteria, thus slowing decomposition. Lagerstätten span geological time from the Cambrian period to the present. Worldwide, some of the best examples of near-perfect fossilization are the Cambrian Maotianshan shales and Burgess Shale, the Devonian Hunsrück Slates, the Jurassic Solnhofen limestone, and the Carboniferous Mazon Creek localities.
+
+Stromatolites are layered accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains by biofilms of microorganisms, especially cyanobacteria.[29] Stromatolites provide some of the most ancient fossil records of life on Earth, dating back more than 3.5 billion years ago.[30]
+
+Stromatolites were much more abundant in Precambrian times. While older, Archean fossil remains are presumed to be colonies of cyanobacteria, younger (that is, Proterozoic) fossils may be primordial forms of the eukaryote chlorophytes (that is, green algae). One genus of stromatolite very common in the geologic record is Collenia. The earliest stromatolite of confirmed microbial origin dates to 2.724 billion years ago.[31]
+
+A 2009 discovery provides strong evidence of microbial stromatolites extending as far back as 3.45 billion years ago.[32][33]
+
+Stromatolites are a major constituent of the fossil record for life's first 3.5 billion years, peaking about 1.25 billion years ago.[32] They subsequently declined in abundance and diversity,[34] which by the start of the Cambrian had fallen to 20% of their peak. The most widely supported explanation is that stromatolite builders fell victims to grazing creatures (the Cambrian substrate revolution), implying that sufficiently complex organisms were common over 1 billion years ago.[35][36][37]
+
+The connection between grazer and stromatolite abundance is well documented in the younger Ordovician evolutionary radiation; stromatolite abundance also increased after the end-Ordovician and end-Permian extinctions decimated marine animals, falling back to earlier levels as marine animals recovered.[38] Fluctuations in metazoan population and diversity may not have been the only factor in the reduction in stromatolite abundance. Factors such as the chemistry of the environment may have been responsible for changes.[39]
+
+While prokaryotic cyanobacteria themselves reproduce asexually through cell division, they were instrumental in priming the environment for the evolutionary development of more complex eukaryotic organisms. Cyanobacteria (as well as extremophile Gammaproteobacteria) are thought to be largely responsible for increasing the amount of oxygen in the primeval earth's atmosphere through their continuing photosynthesis. Cyanobacteria use water, carbon dioxide and sunlight to create their food. A layer of mucus often forms over mats of cyanobacterial cells. In modern microbial mats, debris from the surrounding habitat can become trapped within the mucus, which can be cemented by the calcium carbonate to grow thin laminations of limestone. These laminations can accrete over time, resulting in the banded pattern common to stromatolites. The domal morphology of biological stromatolites is the result of the vertical growth necessary for the continued infiltration of sunlight to the organisms for photosynthesis. Layered spherical growth structures termed oncolites are similar to stromatolites and are also known from the fossil record. Thrombolites are poorly laminated or non-laminated clotted structures formed by cyanobacteria common in the fossil record and in modern sediments.[31]
+
+The Zebra River Canyon area of the Kubis platform in the deeply dissected Zaris Mountains of southwestern Namibia provides an extremely well exposed example of the thrombolite-stromatolite-metazoan reefs that developed during the Proterozoic period, the stromatolites here being better developed in updip locations under conditions of higher current velocities and greater sediment influx.[40]
+
+Index fossils (also known as guide fossils, indicator fossils or zone fossils) are fossils used to define and identify geologic periods (or faunal stages). They work on the premise that, although different sediments may look different depending on the conditions under which they were deposited, they may include the remains of the same species of fossil. The shorter the species' time range, the more precisely different sediments can be correlated, and so rapidly evolving species' fossils are particularly valuable. The best index fossils are common, easy to identify at species level and have a broad distribution—otherwise the likelihood of finding and recognizing one in the two sediments is poor.
+
+Trace fossils consist mainly of tracks and burrows, but also include coprolites (fossil feces) and marks left by feeding.[41][42] Trace fossils are particularly significant because they represent a data source that is not limited to animals with easily fossilized hard parts, and they reflect animal behaviours. Many traces date from significantly earlier than the body fossils of animals that are thought to have been capable of making them.[43] Whilst exact assignment of trace fossils to their makers is generally impossible, traces may for example provide the earliest physical evidence of the appearance of moderately complex animals (comparable to earthworms).[42]
+
+Coprolites are classified as trace fossils as opposed to body fossils, as they give evidence for the animal's behaviour (in this case, diet) rather than morphology. They were first described by William Buckland in 1829. Prior to this they were known as "fossil fir cones" and "bezoar stones." They serve a valuable purpose in paleontology because they provide direct evidence of the predation and diet of extinct organisms.[44] Coprolites may range in size from a few millimetres to over 60 centimetres.
+
+Cambrian trace fossils including Rusophycus, made by a trilobite
+
+A coprolite of a carnivorous dinosaur found in southwestern Saskatchewan
+
+Densely packed, subaerial or nearshore trackways (Climactichnites wilsoni) made by a putative, slug-like mollusk on a Cambrian tidal flat
+
+A transitional fossil is any fossilized remains of a life form that exhibits traits common to both an ancestral group and its derived descendant group.[45] This is especially important where the descendant group is sharply differentiated by gross anatomy and mode of living from the ancestral group. Because of the incompleteness of the fossil record, there is usually no way to know exactly how close a transitional fossil is to the point of divergence. These fossils serve as a reminder that taxonomic divisions are human constructs that have been imposed in hindsight on a continuum of variation.
+
+Microfossil is a descriptive term applied to fossilized plants and animals whose size is just at or below the level at which the fossil can be analyzed by the naked eye. A commonly applied cutoff point between "micro" and "macro" fossils is 1 mm. Microfossils may either be complete (or near-complete) organisms in themselves (such as the marine plankters foraminifera and coccolithophores) or component parts (such as small teeth or spores) of larger animals or plants. Microfossils are of critical importance as a reservoir of paleoclimate information, and are also commonly used by biostratigraphers to assist in the correlation of rock units.
+
+Fossil resin (colloquially called amber) is a natural polymer found in many types of strata throughout the world, even the Arctic. The oldest fossil resin dates to the Triassic, though most dates to the Cenozoic. The excretion of the resin by certain plants is thought to be an evolutionary adaptation for protection from insects and to seal wounds. Fossil resin often contains other fossils called inclusions that were captured by the sticky resin. These include bacteria, fungi, other plants, and animals. Animal inclusions are usually small invertebrates, predominantly arthropods such as insects and spiders, and only extremely rarely a vertebrate such as a small lizard. Preservation of inclusions can be exquisite, including small fragments of DNA.
+
+A derived, reworked or remanié fossil is a fossil found in rock that accumulated significantly later than when the fossilized animal or plant died.[46] Reworked fossils are created by erosion exhuming (freeing) fossils from the rock formation in which they were originally deposited and their redeposition in a younger sedimentary deposit.
+
+Fossil wood is wood that is preserved in the fossil record. Wood is usually the part of a plant that is best preserved (and most easily found). Fossil wood may or may not be petrified. The fossil wood may be the only part of the plant that has been preserved:[47] therefore such wood may get a special kind of botanical name. This will usually include "xylon" and a term indicating its presumed affinity, such as Araucarioxylon (wood of Araucaria or some related genus), Palmoxylon (wood of an indeterminate palm), or Castanoxylon (wood of an indeterminate chinkapin).[48]
+
+The term subfossil can be used to refer to remains, such as bones, nests, or defecations, whose fossilization process is not complete, either because the length of time since the animal involved was living is too short (less than 10,000 years) or because the conditions in which the remains were buried were not optimal for fossilization. Subfossils are often found in caves or other shelters where they can be preserved for thousands of years.[49] The main importance of subfossil vs. fossil remains is that the former contain organic material, which can be used for radiocarbon dating or extraction and sequencing of DNA, protein, or other biomolecules. Additionally, isotope ratios can provide much information about the ecological conditions under which extinct animals lived. Subfossils are useful for studying the evolutionary history of an environment and can be important to studies in paleoclimatology.
+
+Subfossils are often found in depositionary environments, such as lake sediments, oceanic sediments, and soils. Once deposited, physical and chemical weathering can alter the state of preservation.
+
+Chemical fossils, or chemofossils, are chemicals found in rocks and fossil fuels (petroleum, coal, and natural gas) that provide an organic signature for ancient life. Molecular fossils and isotope ratios represent two types of chemical fossils.[50] The oldest traces of life on Earth are fossils of this type, including carbon isotope anomalies found in zircons that imply the existence of life as early as 4.1 billion years ago.[6][7]
+
+It has been suggested that biominerals could be important indicators of extraterrestrial life and thus could play an important role in the search for past or present life on the planet Mars. Furthermore, organic components (biosignatures) that are often associated with biominerals are believed to play crucial roles in both pre-biotic and biotic reactions.[51]
+
+On 24 January 2014, NASA reported that current studies by the Curiosity and Opportunity rovers on Mars will now be searching for evidence of ancient life, including a biosphere based on autotrophic, chemotrophic and/or chemolithoautotrophic microorganisms, as well as ancient water, including fluvio-lacustrine environments (plains related to ancient rivers or lakes) that may have been habitable.[52][53][54][55] The search for evidence of habitability, taphonomy (related to fossils), and organic carbon on the planet Mars is now a primary NASA objective.[52][53]
+
+Pseudofossils are visual patterns in rocks that are produced by geologic processes rather than biologic processes. They can easily be mistaken for real fossils. Some pseudofossils, such as geological dendrite crystals, are formed by naturally occurring fissures in the rock that get filled up by percolating minerals. Other types of pseudofossils are kidney ore (round shapes in iron ore) and moss agates, which look like moss or plant leaves. Concretions, spherical or ovoid-shaped nodules found in some sedimentary strata, were once thought to be dinosaur eggs, and are often mistaken for fossils as well.
+
+Gathering fossils dates at least to the beginning of recorded history. The fossils themselves are referred to as the fossil record. The fossil record was one of the early sources of data underlying the study of evolution and continues to be relevant to the history of life on Earth. Paleontologists examine the fossil record to understand the process of evolution and the way particular species have evolved.
+
+Fossils have been visible and common throughout most of natural history, and so documented human interaction with them goes back as far as recorded history, or earlier.
+
+There are many examples of paleolithic stone knives in Europe, with fossil echinoderms set precisely at the hand grip, going all the way back to Homo heidelbergensis and neanderthals.[56] These ancient peoples also drilled holes through the center of those round fossil shells, apparently using them as beads for necklaces.
+
+The ancient Egyptians gathered fossils of species that resembled the bones of modern species they worshipped. The god Set was associated with the hippopotamus, therefore fossilized bones of hippo-like species were kept in that deity's temples.[57] Five-rayed fossil sea urchin shells were associated with the deity Sopdu, the Morning Star, equivalent of Venus in Roman mythology.[56]
+
+Fossils appear to have directly contributed to the mythology of many civilizations, including the ancient Greeks. Classical Greek historian Herodotos wrote of an area near Hyperborea where gryphons protected golden treasure. There was indeed gold mining in that approximate region, where beaked Protoceratops skulls were common as fossils.
+
+A later Greek scholar, Aristotle, eventually realized that fossil seashells from rocks were similar to those found on the beach, indicating the fossils were once living animals. He had previously explained them in terms of vaporous exhalations,[58] which Persian polymath Avicenna modified into the theory of petrifying fluids (succus lapidificatus). This was built upon in the 14th century by Albert of Saxony, and accepted in some form by most naturalists by the 16th century.[59]
+
+Roman naturalist Pliny the Elder wrote of "tongue stones", which he called glossopetra. These were fossil shark teeth, thought by some classical cultures to look like the tongues of people or snakes.[60] He also wrote about the horns of Ammon, which are fossil ammonites, from whence the species ultimately draws its modern name. Pliny also makes one of the earlier known references to toadstones, thought until the 18th century to be a magical cure for poison originating in the heads of toads, but which are fossil teeth from Lepidotes, a Cretaceous ray-finned fish.[61]
+
+The Plains tribes of North America are thought to have similarly associated fossils, such as the many intact pterosaur fossils naturally exposed in the region, with their own mythology of the thunderbird.[62]
+
+There is no such direct mythological connection known from prehistoric Africa, but there is considerable evidence of tribes there excavating and moving fossils to ceremonial sites, apparently treating them with some reverence.[63]
+
+In Japan, fossil shark teeth were associated with the mythical tengu, thought to be the razor-sharp claws of the creature, documented some time after the 8th century AD.[60]
+
+In medieval China, the fossil bones of ancient mammals including Homo erectus were often mistaken for "dragon bones" and used as medicine and aphrodisiacs. In addition, some of these fossil bones are collected as "art" by scholars, who left scripts on various artifacts, indicating the time they were added to a collection. One good example is the famous scholar Huang Tingjian of the South Song Dynasty during the 11th century, who kept a specific seashell fossil with his own poem engraved on it.[64] In the West fossilized sea creatures on mountainsides were seen as proof of the biblical deluge.
+
+In 1027, the Persian Avicenna explained fossils' stoniness in The Book of Healing:
+
+If what is said concerning the petrifaction of animals and plants is true, the cause of this (phenomenon) is a powerful mineralizing and petrifying virtue which arises in certain stony spots, or emanates suddenly from the earth during earthquake and subsidences, and petrifies whatever comes into contact with it. As a matter of fact, the petrifaction of the bodies of plants and animals is not more extraordinary than the transformation of waters.[65]
+
+From the 13th century to the present day, scholars pointed out that the fossil skulls of Deinotherium giganteum, found in Crete and Greece, might have been interpreted as being the skulls of the Cyclopes of Greek mythology, and are possibly the origin of that Greek myth.[66][67] Their skulls appear to have a single eye-hole in the front, just like their modern elephant cousins, though in fact it's actually the opening for their trunk.
+
+In Norse mythology, echinoderm shells (the round five-part button left over from a sea urchin) were associated with the god Thor, not only being incorporated in thunderstones, representations of Thor's hammer and subsequent hammer-shaped crosses as Christianity was adopted, but also kept in houses to garner Thor's protection.[56]
+
+These grew into the shepherd's crowns of English folklore, used for decoration and as good luck charms, placed by the doorway of homes and churches.[68] In Suffolk, a different species was used as a good-luck charm by bakers, who referred to them as fairy loaves, associating them with the similarly shaped loaves of bread they baked.[69][70]
+
+More scientific views of fossils emerged during the Renaissance. Leonardo da Vinci concurred with Aristotle's view that fossils were the remains of ancient life.[71] For example, da Vinci noticed discrepancies with the biblical flood narrative as an explanation for fossil origins:
+
+If the Deluge had carried the shells for distances of three and four hundred miles from the sea it would have carried them mixed with various other natural objects all heaped up together; but even at such distances from the sea we see the oysters all together and also the shellfish and the cuttlefish and all the other shells which congregate together, found all together dead; and the solitary shells are found apart from one another as we see them every day on the sea-shores.
+
+And we find oysters together in very large families, among which some may be seen with their shells still joined together, indicating that they were left there by the sea and that they were still living when the strait of Gibraltar was cut through. In the mountains of Parma and Piacenza multitudes of shells and corals with holes may be seen still sticking to the rocks...."[72]
+
+In 1666, Nicholas Steno examined a shark, and made the association of its teeth with the "tongue stones" of ancient Greco-Roman mythology, concluding that those were not in fact the tongues of venomous snakes, but the teeth of some long-extinct species of shark.[60]
+
+Robert Hooke (1635-1703) included micrographs of fossils in his Micrographia and was among the first to observe fossil forams. His observations on fossils, which he stated to be the petrified remains of creatures some of which no longer existed, were published posthumously in 1705.[73]
+
+William Smith (1769–1839), an English canal engineer, observed that rocks of different ages (based on the law of superposition) preserved different assemblages of fossils, and that these assemblages succeeded one another in a regular and determinable order. He observed that rocks from distant locations could be correlated based on the fossils they contained. He termed this the principle of faunal succession. This principle became one of Darwin's chief pieces of evidence that biological evolution was real.
+
+Georges Cuvier came to believe that most if not all the animal fossils he examined were remains of extinct species. This led Cuvier to become an active proponent of the geological school of thought called catastrophism. Near the end of his 1796 paper on living and fossil elephants he said:
+
+All of these facts, consistent among themselves, and not opposed by any report, seem to me to prove the existence of a world previous to ours, destroyed by some kind of catastrophe.[74]
+
+Interest in fossils, and geology more generally, expanded during the early nineteenth century.  In Britain, Mary Anning's discoveries of fossils, including the first complete ichthyosaur and a complete plesiosaurus skeleton, sparked both public and scholarly interest.[75]
+
+Early naturalists well understood the similarities and differences of living species leading Linnaeus to develop a hierarchical classification system still in use today. Darwin and his contemporaries first linked the hierarchical structure of the tree of life with the then very sparse fossil record. Darwin eloquently described a process of descent with modification, or evolution, whereby organisms either adapt to natural and changing environmental pressures, or they perish.
+
+When Darwin wrote On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, the oldest animal fossils were those from the Cambrian Period, now known to be about 540 million years old. He worried about the absence of older fossils because of the implications on the validity of his theories, but he expressed hope that such fossils would be found, noting that: "only a small portion of the world is known with accuracy." Darwin also pondered the sudden appearance of many groups (i.e. phyla) in the oldest known Cambrian fossiliferous strata.[76]
+
+Since Darwin's time, the fossil record has been extended to between 2.3 and 3.5 billion years.[77] Most of these Precambrian fossils are microscopic bacteria or microfossils. However, macroscopic fossils are now known from the late Proterozoic. The Ediacara biota (also called Vendian biota) dating from 575 million years ago collectively constitutes a richly diverse assembly of early multicellular eukaryotes.
+
+The fossil record and faunal succession form the basis of the science of biostratigraphy or determining the age of rocks based on embedded fossils. For the first 150 years of geology, biostratigraphy and superposition were the only means for determining the relative age of rocks. The geologic time scale was developed based on the relative ages of rock strata as determined by the early paleontologists and stratigraphers.
+
+Since the early years of the twentieth century, absolute dating methods, such as radiometric dating (including potassium/argon, argon/argon, uranium series, and, for very recent fossils, radiocarbon dating) have been used to verify the relative ages obtained by fossils and to provide absolute ages for many fossils. Radiometric dating has shown that the earliest known stromatolites are over 3.4 billion years old.
+
+The Virtual Fossil Museum[78]
+
+Paleontology has joined with evolutionary biology to share the interdisciplinary task of outlining the tree of life, which inevitably leads backwards in time to Precambrian microscopic life when cell structure and functions evolved. Earth's deep time in the Proterozoic and deeper still in the Archean is only "recounted by microscopic fossils and subtle chemical signals."[79] Molecular biologists, using phylogenetics, can compare protein amino acid or nucleotide sequence homology (i.e., similarity) to evaluate taxonomy and evolutionary distances among organisms, with limited statistical confidence. The study of fossils, on the other hand, can more specifically pinpoint when and in what organism a mutation first appeared. Phylogenetics and paleontology work together in the clarification of science's still dim view of the appearance of life and its evolution.[80]
+
+Niles Eldredge's study of the Phacops trilobite genus supported the hypothesis that modifications to the arrangement of the trilobite's eye lenses proceeded by fits and starts over millions of years during the Devonian.[81] Eldredge's interpretation of the Phacops fossil record was that the aftermaths of the lens changes, but not the rapidly occurring evolutionary process, were fossilized. This and other data led Stephen Jay Gould and Niles Eldredge to publish their seminal paper on punctuated equilibrium in 1971.
+
+Synchrotron X-ray tomographic analysis of early Cambrian bilaterian embryonic microfossils yielded new insights of metazoan evolution at its earliest stages. The tomography technique provides previously unattainable three-dimensional resolution at the limits of fossilization. Fossils of two enigmatic bilaterians, the worm-like Markuelia and a putative, primitive protostome, Pseudooides, provide a peek at germ layer embryonic development. These 543-million-year-old embryos support the emergence of some aspects of arthropod development earlier than previously thought in the late Proterozoic. The preserved embryos from China and Siberia underwent rapid diagenetic phosphatization resulting in exquisite preservation, including cell structures. This research is a notable example of how knowledge encoded by the fossil record continues to contribute otherwise unattainable information on the emergence and development of life on Earth. For example, the research suggests Markuelia has closest affinity to priapulid worms, and is adjacent to the evolutionary branching of Priapulida, Nematoda and Arthropoda.[82]
+
+Fossil trading is the practice of buying and selling fossils. This is many times done illegally with artifacts stolen from research sites, costing many important scientific specimens each year.[83] The problem is quite pronounced in China, where many specimens have been stolen.[84]
+
+Fossil collecting (sometimes, in a non-scientific sense, fossil hunting) is the collection of fossils for scientific study, hobby, or profit. Fossil collecting, as practiced by amateurs, is the predecessor of modern paleontology and many still collect fossils and study fossils as amateurs. Professionals and amateurs alike collect fossils for their scientific value.
+
+These is some medicinal and preventive use for some fossils. Largely the use of fossils as medicine is a matter of placebo effect. However, the consumption of certain fossils has been proven to help against stomach acidity and mineral depletion. The use of fossils to address health issues is rooted in traditional medicine and include the use of fossils as talismans. The specific fossil to use to alleviate or cure an illness is often based on its resemblance of the fossils and the symptoms or affected organ.[85] The use dinosaur bones as "dragon bones" has persisted in Traditional Chinese medicine into modern times, with Mid Cretaceous dinosaur bones being used for the purpose in Ruyang County during the early 21st century.[86]
+
+Three small ammonite fossils, each approximately 1.5 cm across
+
+Eocene fossil fish Priscacara liops from the Green River Formation of Wyoming
+
+A permineralized trilobite, Asaphus kowalewskii
+
+Megalodon and Carcharodontosaurus teeth. The latter was found in the Sahara Desert.
+
+Fossil shrimp (Cretaceous)
+
+Petrified wood in Petrified Forest National Park, Arizona
+
+Petrified cone of Araucaria mirabilis from Patagonia, Argentina dating from the Jurassic Period (approx. 210 Ma)
+
+A fossil gastropod from the Pliocene of Cyprus. A serpulid worm is attached.
+
+Silurian Orthoceras fossil
+
+Eocene fossil flower from Florissant, Colorado
+
+Micraster echinoid fossil from England
+
+Productid brachiopod ventral valve; Roadian, Guadalupian (Middle Permian); Glass Mountains, Texas.
+
+Agatized coral from the Hawthorn Group (Oligocene–Miocene), Florida. An example of preservation by replacement.
+
+Fossils from beaches of the Baltic Sea island of Gotland, placed on paper with 7 mm (0.28 inch) squares
+
+Dinosaur footprints from Torotoro National Park in Bolivia.

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+
+A fossil (from Classical Latin: fossilis, literally "obtained by digging")[1] is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood, oil, coal, and DNA remnants. The totality of fossils is known as the fossil record.
+
+Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old.[2] The oldest fossils are around 3.48 billion years old[3][4][5] to 4.1 billion years old.[6][7] The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absolute ages of rocks and the fossils they host.
+
+There are many processes that lead to fossilization, including permineralization, casts and molds, authigenic mineralization, replacement and recrystallization, adpression, carbonization, and bioimmuration.
+
+Fossils vary in size from one-micrometre (1 µm) bacteria[8] to dinosaurs and trees, many meters long and weighing many tons. A fossil normally preserves only a portion of the deceased organism, usually that portion that was partially mineralized during life, such as the bones and teeth of vertebrates, or the chitinous or calcareous exoskeletons of invertebrates. Fossils may also consist of the marks left behind by the organism while it was alive, such as animal tracks or feces (coprolites). These types of fossil are called trace fossils or ichnofossils, as opposed to body fossils. Some fossils are biochemical and are called chemofossils or biosignatures.
+
+The process of fossilization varies according to tissue type and external conditions.
+
+Permineralization is a process of fossilization that occurs when an organism is buried. The empty spaces within an organism (spaces filled with liquid or gas during life) become filled with mineral-rich groundwater. Minerals precipitate from the groundwater, occupying the empty spaces. This process can occur in very small spaces, such as within the cell wall of a plant cell. Small scale permineralization can produce very detailed fossils. For permineralization to occur, the organism must become covered by sediment soon after death, otherwise decay commences. The degree to which the remains are decayed when covered determines the later details of the fossil. Some fossils consist only of skeletal remains or teeth; other fossils contain traces of skin, feathers or even soft tissues. This is a form of diagenesis.
+
+
+
+In some cases, the original remains of the organism completely dissolve or are otherwise destroyed. The remaining organism-shaped hole in the rock is called an external mold. If this hole is later filled with other minerals, it is a cast. An endocast, or internal mold, is formed when sediments or minerals fill the internal cavity of an organism, such as the inside of a bivalve or snail or the hollow of a skull.
+
+This is a special form of cast and mold formation. If the chemistry is right, the organism (or fragment of organism) can act as a nucleus for the precipitation of minerals such as siderite, resulting in a nodule forming around it. If this happens rapidly before significant decay to the organic tissue, very fine three-dimensional morphological detail can be preserved. Nodules from the Carboniferous Mazon Creek fossil beds of Illinois, USA, are among the best documented examples of such mineralization.
+
+Replacement occurs when the shell, bone or other tissue is replaced with another mineral. In some cases mineral replacement of the original shell occurs so gradually and at such fine scales that microstructural features are preserved despite the total loss of original material. A shell is said to be recrystallized when the original skeletal compounds are still present but in a different crystal form, as from aragonite to calcite.
+
+Compression fossils, such as those of fossil ferns, are the result of chemical reduction of the complex organic molecules composing the organism's tissues. In this case the fossil consists of original material, albeit in a geochemically altered state. This chemical change is an expression of diagenesis. Often what remains is a carbonaceous film known as a phytoleim, in which case the fossil is known as a compression. Often, however, the phytoleim is lost and all that remains is an impression of the organism in the rock—an impression fossil. In many cases, however, compressions and impressions occur together. For instance, when the rock is broken open, the phytoleim will often be attached to one part (compression), whereas the counterpart will just be an impression. For this reason, one term covers the two modes of preservation: adpression.[9]
+
+Because of their antiquity, an unexpected exception to the alteration of an organism's tissues by chemical reduction of the complex organic molecules during fossilization has been the discovery of soft tissue in dinosaur fossils, including blood vessels, and the isolation of proteins and evidence for DNA fragments.[10][11][12][13] In 2014, Mary Schweitzer and her colleagues reported the presence of iron particles (goethite-aFeO(OH)) associated with soft tissues recovered from dinosaur fossils. Based on various experiments that studied the interaction of iron in haemoglobin with blood vessel tissue they proposed that solution hypoxia coupled with iron chelation enhances the stability and preservation of soft tissue and provides the basis for an explanation for the unforeseen preservation of fossil soft tissues.[14] However, a slightly older study based on eight taxa ranging in time from the Devonian to the Jurassic found that reasonably well-preserved fibrils that probably represent collagen were preserved in all these fossils and that the quality of preservation depended mostly on the arrangement of the collagen fibers, with tight packing favoring good preservation.[15] There seemed to be no correlation between geological age and quality of preservation, within that timeframe.
+
+Fossils that are carbonized or coalified consist of the organic remains which have been reduced primarily to the chemical element carbon. Carbonized fossils consist of a thin film which forms a silhouette of the original organism, and the original organic remains were typically soft tissues. Coalified fossils consist primarily of coal, and the original organic remains were typically woody in composition.
+
+Carbonized fossil of a possible leech from the Silurian Waukesha Biota of Wisconsin.
+
+Partially coalified axis (branch) of a lycopod from the Devonian of Wisconsin.
+
+Bioimmuration occurs when a skeletal organism overgrows or otherwise subsumes another organism, preserving the latter, or an impression of it, within the skeleton.[17] Usually it is a sessile skeletal organism, such as a bryozoan or an oyster, which grows along a substrate, covering other sessile sclerobionts. Sometimes the bioimmured organism is soft-bodied and is then preserved in negative relief as a kind of external mold. There are also cases where an organism settles on top of a living skeletal organism that grows upwards, preserving the settler in its skeleton. Bioimmuration is known in the fossil record from the Ordovician[18] to the Recent.[17]
+
+Paleontology seeks to map out how life evolved across geologic time. A substantial hurdle is the difficulty of working out fossil ages. Beds that preserve fossils typically lack the radioactive elements needed for radiometric dating. This technique is our only means of giving rocks greater than about 50 million years old an absolute age, and can be accurate to within 0.5% or better.[19] Although radiometric dating requires careful laboratory work, its basic principle is simple: the rates at which various radioactive elements decay are known, and so the ratio of the radioactive element to its decay products shows how long ago the radioactive element was incorporated into the rock. Radioactive elements are common only in rocks with a volcanic origin, and so the only fossil-bearing rocks that can be dated radiometrically are volcanic ash layers, which may provide termini for the intervening sediments.[19]
+
+Consequently, palaeontologists rely on stratigraphy to date fossils. Stratigraphy is the science of deciphering the "layer-cake" that is the sedimentary record.[20] Rocks normally form relatively horizontal layers, with each layer younger than the one underneath it. If a fossil is found between two layers whose ages are known, the fossil's age is claimed to lie between the two known ages.[21] Because rock sequences are not continuous, but may be broken up by faults or periods of erosion, it is very difficult to match up rock beds that are not directly adjacent. However, fossils of species that survived for a relatively short time can be used to match isolated rocks: this technique is called biostratigraphy. For instance, the conodont Eoplacognathus pseudoplanus has a short range in the Middle Ordovician period.[22] If rocks of unknown age have traces of E. pseudoplanus, they have a mid-Ordovician age. Such index fossils must be distinctive, be globally distributed and occupy a short time range to be useful. Misleading results are produced if the index fossils are incorrectly dated.[23] Stratigraphy and biostratigraphy can in general provide only relative dating (A was before B), which is often sufficient for studying evolution. However, this is difficult for some time periods, because of the problems involved in matching rocks of the same age across continents.[23] Family-tree relationships also help to narrow down the date when lineages first appeared. For instance, if fossils of B or C date to X million years ago and the calculated "family tree" says A was an ancestor of B and C, then A must have evolved earlier.
+
+It is also possible to estimate how long ago two living clades diverged, in other words approximately how long ago their last common ancestor must have lived, by assuming that DNA mutations accumulate at a constant rate. These "molecular clocks", however, are fallible, and provide only approximate timing: for example, they are not sufficiently precise and reliable for estimating when the groups that feature in the Cambrian explosion first evolved,[24] and estimates produced by different techniques may vary by a factor of two.[25]
+
+Organisms are only rarely preserved as fossils in the best of circumstances, and only a fraction of such fossils have been discovered. This is illustrated by the fact that the number of species known through the fossil record is less than 5% of the number of known living species, suggesting that the number of species known through fossils must be far less than 1% of all the species that have ever lived.[26] Because of the specialized and rare circumstances required for a biological structure to fossilize, only a small percentage of life-forms can be expected to be represented in discoveries, and each discovery represents only a snapshot of the process of evolution. The transition itself can only be illustrated and corroborated by transitional fossils, which will never demonstrate an exact half-way point.[27]
+
+The fossil record is strongly biased toward organisms with hard-parts, leaving most groups of soft-bodied organisms with little to no role.[26] It is replete with the mollusks, the vertebrates, the echinoderms, the brachiopods and some groups of arthropods.[28]
+
+Fossil sites with exceptional preservation—sometimes including preserved soft tissues—are known as Lagerstätten—German for "storage places". These formations may have resulted from carcass burial in an anoxic environment with minimal bacteria, thus slowing decomposition. Lagerstätten span geological time from the Cambrian period to the present. Worldwide, some of the best examples of near-perfect fossilization are the Cambrian Maotianshan shales and Burgess Shale, the Devonian Hunsrück Slates, the Jurassic Solnhofen limestone, and the Carboniferous Mazon Creek localities.
+
+Stromatolites are layered accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains by biofilms of microorganisms, especially cyanobacteria.[29] Stromatolites provide some of the most ancient fossil records of life on Earth, dating back more than 3.5 billion years ago.[30]
+
+Stromatolites were much more abundant in Precambrian times. While older, Archean fossil remains are presumed to be colonies of cyanobacteria, younger (that is, Proterozoic) fossils may be primordial forms of the eukaryote chlorophytes (that is, green algae). One genus of stromatolite very common in the geologic record is Collenia. The earliest stromatolite of confirmed microbial origin dates to 2.724 billion years ago.[31]
+
+A 2009 discovery provides strong evidence of microbial stromatolites extending as far back as 3.45 billion years ago.[32][33]
+
+Stromatolites are a major constituent of the fossil record for life's first 3.5 billion years, peaking about 1.25 billion years ago.[32] They subsequently declined in abundance and diversity,[34] which by the start of the Cambrian had fallen to 20% of their peak. The most widely supported explanation is that stromatolite builders fell victims to grazing creatures (the Cambrian substrate revolution), implying that sufficiently complex organisms were common over 1 billion years ago.[35][36][37]
+
+The connection between grazer and stromatolite abundance is well documented in the younger Ordovician evolutionary radiation; stromatolite abundance also increased after the end-Ordovician and end-Permian extinctions decimated marine animals, falling back to earlier levels as marine animals recovered.[38] Fluctuations in metazoan population and diversity may not have been the only factor in the reduction in stromatolite abundance. Factors such as the chemistry of the environment may have been responsible for changes.[39]
+
+While prokaryotic cyanobacteria themselves reproduce asexually through cell division, they were instrumental in priming the environment for the evolutionary development of more complex eukaryotic organisms. Cyanobacteria (as well as extremophile Gammaproteobacteria) are thought to be largely responsible for increasing the amount of oxygen in the primeval earth's atmosphere through their continuing photosynthesis. Cyanobacteria use water, carbon dioxide and sunlight to create their food. A layer of mucus often forms over mats of cyanobacterial cells. In modern microbial mats, debris from the surrounding habitat can become trapped within the mucus, which can be cemented by the calcium carbonate to grow thin laminations of limestone. These laminations can accrete over time, resulting in the banded pattern common to stromatolites. The domal morphology of biological stromatolites is the result of the vertical growth necessary for the continued infiltration of sunlight to the organisms for photosynthesis. Layered spherical growth structures termed oncolites are similar to stromatolites and are also known from the fossil record. Thrombolites are poorly laminated or non-laminated clotted structures formed by cyanobacteria common in the fossil record and in modern sediments.[31]
+
+The Zebra River Canyon area of the Kubis platform in the deeply dissected Zaris Mountains of southwestern Namibia provides an extremely well exposed example of the thrombolite-stromatolite-metazoan reefs that developed during the Proterozoic period, the stromatolites here being better developed in updip locations under conditions of higher current velocities and greater sediment influx.[40]
+
+Index fossils (also known as guide fossils, indicator fossils or zone fossils) are fossils used to define and identify geologic periods (or faunal stages). They work on the premise that, although different sediments may look different depending on the conditions under which they were deposited, they may include the remains of the same species of fossil. The shorter the species' time range, the more precisely different sediments can be correlated, and so rapidly evolving species' fossils are particularly valuable. The best index fossils are common, easy to identify at species level and have a broad distribution—otherwise the likelihood of finding and recognizing one in the two sediments is poor.
+
+Trace fossils consist mainly of tracks and burrows, but also include coprolites (fossil feces) and marks left by feeding.[41][42] Trace fossils are particularly significant because they represent a data source that is not limited to animals with easily fossilized hard parts, and they reflect animal behaviours. Many traces date from significantly earlier than the body fossils of animals that are thought to have been capable of making them.[43] Whilst exact assignment of trace fossils to their makers is generally impossible, traces may for example provide the earliest physical evidence of the appearance of moderately complex animals (comparable to earthworms).[42]
+
+Coprolites are classified as trace fossils as opposed to body fossils, as they give evidence for the animal's behaviour (in this case, diet) rather than morphology. They were first described by William Buckland in 1829. Prior to this they were known as "fossil fir cones" and "bezoar stones." They serve a valuable purpose in paleontology because they provide direct evidence of the predation and diet of extinct organisms.[44] Coprolites may range in size from a few millimetres to over 60 centimetres.
+
+Cambrian trace fossils including Rusophycus, made by a trilobite
+
+A coprolite of a carnivorous dinosaur found in southwestern Saskatchewan
+
+Densely packed, subaerial or nearshore trackways (Climactichnites wilsoni) made by a putative, slug-like mollusk on a Cambrian tidal flat
+
+A transitional fossil is any fossilized remains of a life form that exhibits traits common to both an ancestral group and its derived descendant group.[45] This is especially important where the descendant group is sharply differentiated by gross anatomy and mode of living from the ancestral group. Because of the incompleteness of the fossil record, there is usually no way to know exactly how close a transitional fossil is to the point of divergence. These fossils serve as a reminder that taxonomic divisions are human constructs that have been imposed in hindsight on a continuum of variation.
+
+Microfossil is a descriptive term applied to fossilized plants and animals whose size is just at or below the level at which the fossil can be analyzed by the naked eye. A commonly applied cutoff point between "micro" and "macro" fossils is 1 mm. Microfossils may either be complete (or near-complete) organisms in themselves (such as the marine plankters foraminifera and coccolithophores) or component parts (such as small teeth or spores) of larger animals or plants. Microfossils are of critical importance as a reservoir of paleoclimate information, and are also commonly used by biostratigraphers to assist in the correlation of rock units.
+
+Fossil resin (colloquially called amber) is a natural polymer found in many types of strata throughout the world, even the Arctic. The oldest fossil resin dates to the Triassic, though most dates to the Cenozoic. The excretion of the resin by certain plants is thought to be an evolutionary adaptation for protection from insects and to seal wounds. Fossil resin often contains other fossils called inclusions that were captured by the sticky resin. These include bacteria, fungi, other plants, and animals. Animal inclusions are usually small invertebrates, predominantly arthropods such as insects and spiders, and only extremely rarely a vertebrate such as a small lizard. Preservation of inclusions can be exquisite, including small fragments of DNA.
+
+A derived, reworked or remanié fossil is a fossil found in rock that accumulated significantly later than when the fossilized animal or plant died.[46] Reworked fossils are created by erosion exhuming (freeing) fossils from the rock formation in which they were originally deposited and their redeposition in a younger sedimentary deposit.
+
+Fossil wood is wood that is preserved in the fossil record. Wood is usually the part of a plant that is best preserved (and most easily found). Fossil wood may or may not be petrified. The fossil wood may be the only part of the plant that has been preserved:[47] therefore such wood may get a special kind of botanical name. This will usually include "xylon" and a term indicating its presumed affinity, such as Araucarioxylon (wood of Araucaria or some related genus), Palmoxylon (wood of an indeterminate palm), or Castanoxylon (wood of an indeterminate chinkapin).[48]
+
+The term subfossil can be used to refer to remains, such as bones, nests, or defecations, whose fossilization process is not complete, either because the length of time since the animal involved was living is too short (less than 10,000 years) or because the conditions in which the remains were buried were not optimal for fossilization. Subfossils are often found in caves or other shelters where they can be preserved for thousands of years.[49] The main importance of subfossil vs. fossil remains is that the former contain organic material, which can be used for radiocarbon dating or extraction and sequencing of DNA, protein, or other biomolecules. Additionally, isotope ratios can provide much information about the ecological conditions under which extinct animals lived. Subfossils are useful for studying the evolutionary history of an environment and can be important to studies in paleoclimatology.
+
+Subfossils are often found in depositionary environments, such as lake sediments, oceanic sediments, and soils. Once deposited, physical and chemical weathering can alter the state of preservation.
+
+Chemical fossils, or chemofossils, are chemicals found in rocks and fossil fuels (petroleum, coal, and natural gas) that provide an organic signature for ancient life. Molecular fossils and isotope ratios represent two types of chemical fossils.[50] The oldest traces of life on Earth are fossils of this type, including carbon isotope anomalies found in zircons that imply the existence of life as early as 4.1 billion years ago.[6][7]
+
+It has been suggested that biominerals could be important indicators of extraterrestrial life and thus could play an important role in the search for past or present life on the planet Mars. Furthermore, organic components (biosignatures) that are often associated with biominerals are believed to play crucial roles in both pre-biotic and biotic reactions.[51]
+
+On 24 January 2014, NASA reported that current studies by the Curiosity and Opportunity rovers on Mars will now be searching for evidence of ancient life, including a biosphere based on autotrophic, chemotrophic and/or chemolithoautotrophic microorganisms, as well as ancient water, including fluvio-lacustrine environments (plains related to ancient rivers or lakes) that may have been habitable.[52][53][54][55] The search for evidence of habitability, taphonomy (related to fossils), and organic carbon on the planet Mars is now a primary NASA objective.[52][53]
+
+Pseudofossils are visual patterns in rocks that are produced by geologic processes rather than biologic processes. They can easily be mistaken for real fossils. Some pseudofossils, such as geological dendrite crystals, are formed by naturally occurring fissures in the rock that get filled up by percolating minerals. Other types of pseudofossils are kidney ore (round shapes in iron ore) and moss agates, which look like moss or plant leaves. Concretions, spherical or ovoid-shaped nodules found in some sedimentary strata, were once thought to be dinosaur eggs, and are often mistaken for fossils as well.
+
+Gathering fossils dates at least to the beginning of recorded history. The fossils themselves are referred to as the fossil record. The fossil record was one of the early sources of data underlying the study of evolution and continues to be relevant to the history of life on Earth. Paleontologists examine the fossil record to understand the process of evolution and the way particular species have evolved.
+
+Fossils have been visible and common throughout most of natural history, and so documented human interaction with them goes back as far as recorded history, or earlier.
+
+There are many examples of paleolithic stone knives in Europe, with fossil echinoderms set precisely at the hand grip, going all the way back to Homo heidelbergensis and neanderthals.[56] These ancient peoples also drilled holes through the center of those round fossil shells, apparently using them as beads for necklaces.
+
+The ancient Egyptians gathered fossils of species that resembled the bones of modern species they worshipped. The god Set was associated with the hippopotamus, therefore fossilized bones of hippo-like species were kept in that deity's temples.[57] Five-rayed fossil sea urchin shells were associated with the deity Sopdu, the Morning Star, equivalent of Venus in Roman mythology.[56]
+
+Fossils appear to have directly contributed to the mythology of many civilizations, including the ancient Greeks. Classical Greek historian Herodotos wrote of an area near Hyperborea where gryphons protected golden treasure. There was indeed gold mining in that approximate region, where beaked Protoceratops skulls were common as fossils.
+
+A later Greek scholar, Aristotle, eventually realized that fossil seashells from rocks were similar to those found on the beach, indicating the fossils were once living animals. He had previously explained them in terms of vaporous exhalations,[58] which Persian polymath Avicenna modified into the theory of petrifying fluids (succus lapidificatus). This was built upon in the 14th century by Albert of Saxony, and accepted in some form by most naturalists by the 16th century.[59]
+
+Roman naturalist Pliny the Elder wrote of "tongue stones", which he called glossopetra. These were fossil shark teeth, thought by some classical cultures to look like the tongues of people or snakes.[60] He also wrote about the horns of Ammon, which are fossil ammonites, from whence the species ultimately draws its modern name. Pliny also makes one of the earlier known references to toadstones, thought until the 18th century to be a magical cure for poison originating in the heads of toads, but which are fossil teeth from Lepidotes, a Cretaceous ray-finned fish.[61]
+
+The Plains tribes of North America are thought to have similarly associated fossils, such as the many intact pterosaur fossils naturally exposed in the region, with their own mythology of the thunderbird.[62]
+
+There is no such direct mythological connection known from prehistoric Africa, but there is considerable evidence of tribes there excavating and moving fossils to ceremonial sites, apparently treating them with some reverence.[63]
+
+In Japan, fossil shark teeth were associated with the mythical tengu, thought to be the razor-sharp claws of the creature, documented some time after the 8th century AD.[60]
+
+In medieval China, the fossil bones of ancient mammals including Homo erectus were often mistaken for "dragon bones" and used as medicine and aphrodisiacs. In addition, some of these fossil bones are collected as "art" by scholars, who left scripts on various artifacts, indicating the time they were added to a collection. One good example is the famous scholar Huang Tingjian of the South Song Dynasty during the 11th century, who kept a specific seashell fossil with his own poem engraved on it.[64] In the West fossilized sea creatures on mountainsides were seen as proof of the biblical deluge.
+
+In 1027, the Persian Avicenna explained fossils' stoniness in The Book of Healing:
+
+If what is said concerning the petrifaction of animals and plants is true, the cause of this (phenomenon) is a powerful mineralizing and petrifying virtue which arises in certain stony spots, or emanates suddenly from the earth during earthquake and subsidences, and petrifies whatever comes into contact with it. As a matter of fact, the petrifaction of the bodies of plants and animals is not more extraordinary than the transformation of waters.[65]
+
+From the 13th century to the present day, scholars pointed out that the fossil skulls of Deinotherium giganteum, found in Crete and Greece, might have been interpreted as being the skulls of the Cyclopes of Greek mythology, and are possibly the origin of that Greek myth.[66][67] Their skulls appear to have a single eye-hole in the front, just like their modern elephant cousins, though in fact it's actually the opening for their trunk.
+
+In Norse mythology, echinoderm shells (the round five-part button left over from a sea urchin) were associated with the god Thor, not only being incorporated in thunderstones, representations of Thor's hammer and subsequent hammer-shaped crosses as Christianity was adopted, but also kept in houses to garner Thor's protection.[56]
+
+These grew into the shepherd's crowns of English folklore, used for decoration and as good luck charms, placed by the doorway of homes and churches.[68] In Suffolk, a different species was used as a good-luck charm by bakers, who referred to them as fairy loaves, associating them with the similarly shaped loaves of bread they baked.[69][70]
+
+More scientific views of fossils emerged during the Renaissance. Leonardo da Vinci concurred with Aristotle's view that fossils were the remains of ancient life.[71] For example, da Vinci noticed discrepancies with the biblical flood narrative as an explanation for fossil origins:
+
+If the Deluge had carried the shells for distances of three and four hundred miles from the sea it would have carried them mixed with various other natural objects all heaped up together; but even at such distances from the sea we see the oysters all together and also the shellfish and the cuttlefish and all the other shells which congregate together, found all together dead; and the solitary shells are found apart from one another as we see them every day on the sea-shores.
+
+And we find oysters together in very large families, among which some may be seen with their shells still joined together, indicating that they were left there by the sea and that they were still living when the strait of Gibraltar was cut through. In the mountains of Parma and Piacenza multitudes of shells and corals with holes may be seen still sticking to the rocks...."[72]
+
+In 1666, Nicholas Steno examined a shark, and made the association of its teeth with the "tongue stones" of ancient Greco-Roman mythology, concluding that those were not in fact the tongues of venomous snakes, but the teeth of some long-extinct species of shark.[60]
+
+Robert Hooke (1635-1703) included micrographs of fossils in his Micrographia and was among the first to observe fossil forams. His observations on fossils, which he stated to be the petrified remains of creatures some of which no longer existed, were published posthumously in 1705.[73]
+
+William Smith (1769–1839), an English canal engineer, observed that rocks of different ages (based on the law of superposition) preserved different assemblages of fossils, and that these assemblages succeeded one another in a regular and determinable order. He observed that rocks from distant locations could be correlated based on the fossils they contained. He termed this the principle of faunal succession. This principle became one of Darwin's chief pieces of evidence that biological evolution was real.
+
+Georges Cuvier came to believe that most if not all the animal fossils he examined were remains of extinct species. This led Cuvier to become an active proponent of the geological school of thought called catastrophism. Near the end of his 1796 paper on living and fossil elephants he said:
+
+All of these facts, consistent among themselves, and not opposed by any report, seem to me to prove the existence of a world previous to ours, destroyed by some kind of catastrophe.[74]
+
+Interest in fossils, and geology more generally, expanded during the early nineteenth century.  In Britain, Mary Anning's discoveries of fossils, including the first complete ichthyosaur and a complete plesiosaurus skeleton, sparked both public and scholarly interest.[75]
+
+Early naturalists well understood the similarities and differences of living species leading Linnaeus to develop a hierarchical classification system still in use today. Darwin and his contemporaries first linked the hierarchical structure of the tree of life with the then very sparse fossil record. Darwin eloquently described a process of descent with modification, or evolution, whereby organisms either adapt to natural and changing environmental pressures, or they perish.
+
+When Darwin wrote On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, the oldest animal fossils were those from the Cambrian Period, now known to be about 540 million years old. He worried about the absence of older fossils because of the implications on the validity of his theories, but he expressed hope that such fossils would be found, noting that: "only a small portion of the world is known with accuracy." Darwin also pondered the sudden appearance of many groups (i.e. phyla) in the oldest known Cambrian fossiliferous strata.[76]
+
+Since Darwin's time, the fossil record has been extended to between 2.3 and 3.5 billion years.[77] Most of these Precambrian fossils are microscopic bacteria or microfossils. However, macroscopic fossils are now known from the late Proterozoic. The Ediacara biota (also called Vendian biota) dating from 575 million years ago collectively constitutes a richly diverse assembly of early multicellular eukaryotes.
+
+The fossil record and faunal succession form the basis of the science of biostratigraphy or determining the age of rocks based on embedded fossils. For the first 150 years of geology, biostratigraphy and superposition were the only means for determining the relative age of rocks. The geologic time scale was developed based on the relative ages of rock strata as determined by the early paleontologists and stratigraphers.
+
+Since the early years of the twentieth century, absolute dating methods, such as radiometric dating (including potassium/argon, argon/argon, uranium series, and, for very recent fossils, radiocarbon dating) have been used to verify the relative ages obtained by fossils and to provide absolute ages for many fossils. Radiometric dating has shown that the earliest known stromatolites are over 3.4 billion years old.
+
+The Virtual Fossil Museum[78]
+
+Paleontology has joined with evolutionary biology to share the interdisciplinary task of outlining the tree of life, which inevitably leads backwards in time to Precambrian microscopic life when cell structure and functions evolved. Earth's deep time in the Proterozoic and deeper still in the Archean is only "recounted by microscopic fossils and subtle chemical signals."[79] Molecular biologists, using phylogenetics, can compare protein amino acid or nucleotide sequence homology (i.e., similarity) to evaluate taxonomy and evolutionary distances among organisms, with limited statistical confidence. The study of fossils, on the other hand, can more specifically pinpoint when and in what organism a mutation first appeared. Phylogenetics and paleontology work together in the clarification of science's still dim view of the appearance of life and its evolution.[80]
+
+Niles Eldredge's study of the Phacops trilobite genus supported the hypothesis that modifications to the arrangement of the trilobite's eye lenses proceeded by fits and starts over millions of years during the Devonian.[81] Eldredge's interpretation of the Phacops fossil record was that the aftermaths of the lens changes, but not the rapidly occurring evolutionary process, were fossilized. This and other data led Stephen Jay Gould and Niles Eldredge to publish their seminal paper on punctuated equilibrium in 1971.
+
+Synchrotron X-ray tomographic analysis of early Cambrian bilaterian embryonic microfossils yielded new insights of metazoan evolution at its earliest stages. The tomography technique provides previously unattainable three-dimensional resolution at the limits of fossilization. Fossils of two enigmatic bilaterians, the worm-like Markuelia and a putative, primitive protostome, Pseudooides, provide a peek at germ layer embryonic development. These 543-million-year-old embryos support the emergence of some aspects of arthropod development earlier than previously thought in the late Proterozoic. The preserved embryos from China and Siberia underwent rapid diagenetic phosphatization resulting in exquisite preservation, including cell structures. This research is a notable example of how knowledge encoded by the fossil record continues to contribute otherwise unattainable information on the emergence and development of life on Earth. For example, the research suggests Markuelia has closest affinity to priapulid worms, and is adjacent to the evolutionary branching of Priapulida, Nematoda and Arthropoda.[82]
+
+Fossil trading is the practice of buying and selling fossils. This is many times done illegally with artifacts stolen from research sites, costing many important scientific specimens each year.[83] The problem is quite pronounced in China, where many specimens have been stolen.[84]
+
+Fossil collecting (sometimes, in a non-scientific sense, fossil hunting) is the collection of fossils for scientific study, hobby, or profit. Fossil collecting, as practiced by amateurs, is the predecessor of modern paleontology and many still collect fossils and study fossils as amateurs. Professionals and amateurs alike collect fossils for their scientific value.
+
+These is some medicinal and preventive use for some fossils. Largely the use of fossils as medicine is a matter of placebo effect. However, the consumption of certain fossils has been proven to help against stomach acidity and mineral depletion. The use of fossils to address health issues is rooted in traditional medicine and include the use of fossils as talismans. The specific fossil to use to alleviate or cure an illness is often based on its resemblance of the fossils and the symptoms or affected organ.[85] The use dinosaur bones as "dragon bones" has persisted in Traditional Chinese medicine into modern times, with Mid Cretaceous dinosaur bones being used for the purpose in Ruyang County during the early 21st century.[86]
+
+Three small ammonite fossils, each approximately 1.5 cm across
+
+Eocene fossil fish Priscacara liops from the Green River Formation of Wyoming
+
+A permineralized trilobite, Asaphus kowalewskii
+
+Megalodon and Carcharodontosaurus teeth. The latter was found in the Sahara Desert.
+
+Fossil shrimp (Cretaceous)
+
+Petrified wood in Petrified Forest National Park, Arizona
+
+Petrified cone of Araucaria mirabilis from Patagonia, Argentina dating from the Jurassic Period (approx. 210 Ma)
+
+A fossil gastropod from the Pliocene of Cyprus. A serpulid worm is attached.
+
+Silurian Orthoceras fossil
+
+Eocene fossil flower from Florissant, Colorado
+
+Micraster echinoid fossil from England
+
+Productid brachiopod ventral valve; Roadian, Guadalupian (Middle Permian); Glass Mountains, Texas.
+
+Agatized coral from the Hawthorn Group (Oligocene–Miocene), Florida. An example of preservation by replacement.
+
+Fossils from beaches of the Baltic Sea island of Gotland, placed on paper with 7 mm (0.28 inch) squares
+
+Dinosaur footprints from Torotoro National Park in Bolivia.

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+Amphibians are ectothermic, tetrapod vertebrates of the class Amphibia. Modern amphibians are all Lissamphibia. They inhabit a wide variety of habitats, with most species living within terrestrial, fossorial, arboreal or freshwater aquatic ecosystems. Thus amphibians typically start out as larvae living in water, but some species have developed behavioural adaptations to bypass this.
+
+The young generally undergo metamorphosis from larva with gills to an adult air-breathing form with lungs. Amphibians use their skin as a secondary respiratory surface and some small terrestrial salamanders and frogs lack lungs and rely entirely on their skin. They are superficially similar to lizards but, along with mammals and birds, reptiles are amniotes and do not require water bodies in which to breed. With their complex reproductive needs and permeable skins, amphibians are often ecological indicators; in recent decades there has been a dramatic decline in amphibian populations for many species around the globe.
+
+The earliest amphibians evolved in the Devonian period from sarcopterygian fish with lungs and bony-limbed fins, features that were helpful in adapting to dry land. They diversified and became dominant during the Carboniferous and Permian periods, but were later displaced by reptiles and other vertebrates. Over time, amphibians shrank in size and decreased in diversity, leaving only the modern subclass Lissamphibia.
+
+The three modern orders of amphibians are Anura (the frogs and toads), Urodela (the salamanders), and Apoda (the caecilians). The number of known amphibian species is approximately 8,000, of which nearly 90% are frogs. The smallest amphibian (and vertebrate) in the world is a frog from New Guinea (Paedophryne amauensis) with a length of just 7.7 mm (0.30 in). The largest living amphibian is the 1.8 m (5 ft 11 in) South China giant salamander (Andrias sligoi), but this is dwarfed by the extinct 9 m (30 ft) Prionosuchus from the middle Permian of Brazil. The study of amphibians is called batrachology, while the study of both reptiles and amphibians is called herpetology.
+
+The word "amphibian" is derived from the Ancient Greek term ἀμφίβιος (amphíbios), which means "both kinds of life", ἀμφί meaning "of both kinds" and βιος meaning "life". The term was initially used as a general adjective for animals that could live on land or in water, including seals and otters.[2] Traditionally, the class Amphibia includes all tetrapod vertebrates that are not amniotes. Amphibia in its widest sense (sensu lato) was divided into three subclasses, two of which are extinct:[3]
+
+The actual number of species in each group depends on the taxonomic classification followed. The two most common systems are the classification adopted by the website AmphibiaWeb, University of California, Berkeley and the classification by herpetologist Darrel Frost and the American Museum of Natural History, available as the online reference database "Amphibian Species of the World".[4] The numbers of species cited above follows Frost and the total number of known amphibian species as of March 31, 2019 is exactly 8,000,[5] of which nearly 90% are frogs.[6]
+
+With the phylogenetic classification, the taxon Labyrinthodontia has been discarded as it is a polyparaphyletic group without unique defining features apart from shared primitive characteristics. Classification varies according to the preferred phylogeny of the author and whether they use a stem-based or a node-based classification. Traditionally, amphibians as a class are defined as all tetrapods with a larval stage, while the group that includes the common ancestors of all living amphibians (frogs, salamanders and caecilians) and all their descendants is called Lissamphibia. The phylogeny of Paleozoic amphibians is uncertain, and Lissamphibia may possibly fall within extinct groups, like the Temnospondyli (traditionally placed in the subclass Labyrinthodontia) or the Lepospondyli, and in some analyses even in the amniotes. This means that advocates of phylogenetic nomenclature have removed a large number of basal Devonian and Carboniferous amphibian-type tetrapod groups that were formerly placed in Amphibia in Linnaean taxonomy, and included them elsewhere under cladistic taxonomy.[1] If the common ancestor of amphibians and amniotes is included in Amphibia, it becomes a paraphyletic group.[7]
+
+All modern amphibians are included in the subclass Lissamphibia, which is usually considered a clade, a group of species that have evolved from a common ancestor. The three modern orders are Anura (the frogs and toads), Caudata (or Urodela, the salamanders), and Gymnophiona (or Apoda, the caecilians).[8] It has been suggested that salamanders arose separately from a Temnospondyl-like ancestor, and even that caecilians are the sister group of the advanced reptiliomorph amphibians, and thus of amniotes.[9] Although the fossils of several older proto-frogs with primitive characteristics are known, the oldest "true frog" is Prosalirus bitis, from the Early Jurassic Kayenta Formation of Arizona. It is anatomically very similar to modern frogs.[10] The oldest known caecilian is another Early Jurassic species, Eocaecilia micropodia, also from Arizona.[11] The earliest salamander is Beiyanerpeton jianpingensis from the Late Jurassic of northeastern China.[12]
+
+Authorities disagree as to whether Salientia is a superorder that includes the order Anura, or whether Anura is a sub-order of the order Salientia. The Lissamphibia are traditionally divided into three orders, but an extinct salamander-like family, the Albanerpetontidae, is now considered part of Lissamphibia alongside the superorder Salientia. Furthermore, Salientia includes all three recent orders plus the Triassic proto-frog, Triadobatrachus.[13]
+
+The first major groups of amphibians developed in the Devonian period, around 370 million years ago, from lobe-finned fish which were similar to the modern coelacanth and lungfish.[14] These ancient lobe-finned fish had evolved multi-jointed leg-like fins with digits that enabled them to crawl along the sea bottom. Some fish had developed primitive lungs that help them breathe air when the stagnant pools of the Devonian swamps were low in oxygen. They could also use their strong fins to hoist themselves out of the water and onto dry land if circumstances so required. Eventually, their bony fins would evolve into limbs and they would become the ancestors to all tetrapods, including modern amphibians, reptiles, birds, and mammals. Despite being able to crawl on land, many of these prehistoric tetrapodomorph fish still spent most of their time in the water. They had started to develop lungs, but still breathed predominantly with gills.[15]
+
+Many examples of species showing transitional features have been discovered. Ichthyostega was one of the first primitive amphibians, with nostrils and more efficient lungs. It had four sturdy limbs, a neck, a tail with fins and a skull very similar to that of the lobe-finned fish, Eusthenopteron.[14] Amphibians evolved adaptations that allowed them to stay out of the water for longer periods. Their lungs improved and their skeletons became heavier and stronger, better able to support the weight of their bodies on land. They developed "hands" and "feet" with five or more digits;[16] the skin became more capable of retaining body fluids and resisting desiccation.[15] The fish's hyomandibula bone in the hyoid region behind the gills diminished in size and became the stapes of the amphibian ear, an adaptation necessary for hearing on dry land.[17] An affinity between the amphibians and the teleost fish is the multi-folded structure of the teeth and the paired supra-occipital bones at the back of the head, neither of these features being found elsewhere in the animal kingdom.[18]
+
+At the end of the Devonian period (360 million years ago), the seas, rivers and lakes were teeming with life while the land was the realm of early plants and devoid of vertebrates,[18] though some, such as Ichthyostega, may have sometimes hauled themselves out of the water. It is thought they may have propelled themselves with their forelimbs, dragging their hindquarters in a similar manner to that used by the elephant seal.[16] In the early Carboniferous (360 to 345 million years ago), the climate became wet and warm. Extensive swamps developed with mosses, ferns, horsetails and calamites. Air-breathing arthropods evolved and invaded the land where they provided food for the carnivorous amphibians that began to adapt to the terrestrial environment. There were no other tetrapods on the land and the amphibians were at the top of the food chain, occupying the ecological position currently held by the crocodile. Though equipped with limbs and the ability to breathe air, most still had a long tapering body and strong tail.[18] They were the top land predators, sometimes reaching several metres in length, preying on the large insects of the period and the many types of fish in the water. They still needed to return to water to lay their shell-less eggs, and even most modern amphibians have a fully aquatic larval stage with gills like their fish ancestors. It was the development of the amniotic egg, which prevents the developing embryo from drying out, that enabled the reptiles to reproduce on land and which led to their dominance in the period that followed.[14]
+
+After the Carboniferous rainforest collapse amphibian dominance gave way to reptiles,[19] and amphibians were further devastated by the Permian–Triassic extinction event.[20] During the Triassic Period (250 to 200 million years ago), the reptiles continued to out-compete the amphibians, leading to a reduction in both the amphibians' size and their importance in the biosphere. According to the fossil record, Lissamphibia, which includes all modern amphibians and is the only surviving lineage, may have branched off from the extinct groups Temnospondyli and Lepospondyli at some period between the Late Carboniferous and the Early Triassic. The relative scarcity of fossil evidence precludes precise dating,[15] but the most recent molecular study, based on multilocus sequence typing, suggests a Late Carboniferous/Early Permian origin for extant amphibians.[21]
+
+The origins and evolutionary relationships between the three main groups of amphibians is a matter of debate. A 2005 molecular phylogeny, based on rDNA analysis, suggests that salamanders and caecilians are more closely related to each other than they are to frogs. It also appears that the divergence of the three groups took place in the Paleozoic or early Mesozoic (around 250 million years ago), before the breakup of the supercontinent Pangaea and soon after their divergence from the lobe-finned fish. The briefness of this period, and the swiftness with which radiation took place, would help account for the relative scarcity of primitive amphibian fossils.[22] There are large gaps in the fossil record, but the discovery of a Gerobatrachus hottoni from the Early Permian in Texas in 2008 provided a missing link with many of the characteristics of modern frogs.[9] Molecular analysis suggests that the frog–salamander divergence took place considerably earlier than the palaeontological evidence indicates.[9] Newer research indicates that the common ancestor of all Lissamphibians lived about 315 million years ago, and that stereospondyls are the closest relatives to the caecilians.[23]
+
+As they evolved from lunged fish, amphibians had to make certain adaptations for living on land, including the need to develop new means of locomotion. In the water, the sideways thrusts of their tails had propelled them forward, but on land, quite different mechanisms were required. Their vertebral columns, limbs, limb girdles and musculature needed to be strong enough to raise them off the ground for locomotion and feeding. Terrestrial adults discarded their lateral line systems and adapted their sensory systems to receive stimuli via the medium of the air. They needed to develop new methods to regulate their body heat to cope with fluctuations in ambient temperature. They developed behaviours suitable for reproduction in a terrestrial environment. Their skins were exposed to harmful ultraviolet rays that had previously been absorbed by the water. The skin changed to become more protective and prevent excessive water loss.[24]
+
+The superclass Tetrapoda is divided into four classes of vertebrate animals with four limbs.[25] Reptiles, birds and mammals are amniotes, the eggs of which are either laid or carried by the female and are surrounded by several membranes, some of which are impervious.[26] Lacking these membranes, amphibians require water bodies for reproduction, although some species have developed various strategies for protecting or bypassing the vulnerable aquatic larval stage.[24] They are not found in the sea with the exception of one or two frogs that live in brackish water in mangrove swamps;[27] the Anderson's salamander meanwhile occurs in brackish or salt water lakes.[28] On land, amphibians are restricted to moist habitats because of the need to keep their skin damp.[24]
+
+Modern amphibians have a simplified anatomy compared to their ancestors due to paedomorphosis, caused by two evolutionary trends: miniaturization and an unusually large genome, which result in a slower growth and development rate compared to other vertebrates.[29][30] Another reason for their size is associated with their rapid metamorphosis, which seems to have evolved only in the ancestors of lissamphibia; in all other known lines the development was much more gradual. Because a remodeling of the feeding apparatus means they don't eat during the metamorphosis, the metamorphosis has to go faster the smaller the individual is, so it happens at an early stage when the larvae are still small. (The largest species of salamanders don't go through a metamorphosis.)[31] Amphibians that lay eggs on land often go through the whole metamorphosis inside the egg. An anamniotic terrestrial egg is less than 1 cm in diameter due to diffusion problems, a size which puts a limit on the amount of posthatching growth.[32]
+
+The smallest amphibian (and vertebrate) in the world is a microhylid frog from New Guinea (Paedophryne amauensis) first discovered in 2012. It has an average length of 7.7 mm (0.30 in) and is part of a genus that contains four of the world's ten smallest frog species.[33] The largest living amphibian is the 1.8 m (5 ft 11 in) Chinese giant salamander (Andrias davidianus)[34] but this is a great deal smaller than the largest amphibian that ever existed—the extinct 9 m (30 ft) Prionosuchus, a crocodile-like temnospondyl dating to 270 million years ago from the middle Permian of Brazil.[35] The largest frog is the African Goliath frog (Conraua goliath), which can reach 32 cm (13 in) and weigh 3 kg (6.6 lb).[34]
+
+Amphibians are ectothermic (cold-blooded) vertebrates that do not maintain their body temperature through internal physiological processes. Their metabolic rate is low and as a result, their food and energy requirements are limited. In the adult state, they have tear ducts and movable eyelids, and most species have ears that can detect airborne or ground vibrations. They have muscular tongues, which in many species can be protruded. Modern amphibians have fully ossified vertebrae with articular processes. Their ribs are usually short and may be fused to the vertebrae. Their skulls are mostly broad and short, and are often incompletely ossified. Their skin contains little keratin and lacks scales, apart from a few fish-like scales in certain caecilians. The skin contains many mucous glands and in some species, poison glands (a type of granular gland). The hearts of amphibians have three chambers, two atria and one ventricle. They have a urinary bladder and nitrogenous waste products are excreted primarily as urea. Most amphibians lay their eggs in water and have aquatic larvae that undergo metamorphosis to become terrestrial adults. Amphibians breathe by means of a pump action in which air is first drawn into the buccopharyngeal region through the nostrils. These are then closed and the air is forced into the lungs by contraction of the throat.[36] They supplement this with gas exchange through the skin.[24]
+
+The order Anura (from the Ancient Greek a(n)- meaning "without" and oura meaning "tail") comprises the frogs and toads. They usually have long hind limbs that fold underneath them, shorter forelimbs, webbed toes with no claws, no tails, large eyes and glandular moist skin.[8] Members of this order with smooth skins are commonly referred to as frogs, while those with warty skins are known as toads. The difference is not a formal one taxonomically and there are numerous exceptions to this rule. Members of the family Bufonidae are known as the "true toads".[37] Frogs range in size from the 30-centimetre (12 in) Goliath frog (Conraua goliath) of West Africa[38] to the 7.7-millimetre (0.30 in) Paedophryne amauensis, first described in Papua New Guinea in 2012, which is also the smallest known vertebrate.[39] Although most species are associated with water and damp habitats, some are specialised to live in trees or in deserts. They are found worldwide except for polar areas.[40]
+
+Anura is divided into three suborders that are broadly accepted by the scientific community, but the relationships between some families remain unclear. Future molecular studies should provide further insights into their evolutionary relationships.[41] The suborder Archaeobatrachia contains four families of primitive frogs. These are Ascaphidae, Bombinatoridae, Discoglossidae and Leiopelmatidae which have few derived features and are probably paraphyletic with regard to other frog lineages.[42] The six families in the more evolutionarily advanced suborder Mesobatrachia are the fossorial Megophryidae, Pelobatidae, Pelodytidae, Scaphiopodidae and Rhinophrynidae and the obligatorily aquatic Pipidae. These have certain characteristics that are intermediate between the two other suborders.[42] Neobatrachia is by far the largest suborder and includes the remaining families of modern frogs, including most common species. Ninety-six percent of the over 5,000 extant species of frog are neobatrachians.[43]
+
+The order Caudata (from the Latin cauda meaning "tail") consists of the salamanders—elongated, low-slung animals that mostly resemble lizards in form. This is a symplesiomorphic trait and they are no more closely related to lizards than they are to mammals.[44] Salamanders lack claws, have scale-free skins, either smooth or covered with tubercles, and tails that are usually flattened from side to side and often finned. They range in size from the Chinese giant salamander (Andrias davidianus), which has been reported to grow to a length of 1.8 metres (5 ft 11 in),[45] to the diminutive Thorius pennatulus from Mexico which seldom exceeds 20 mm (0.8 in) in length.[46] Salamanders have a mostly Laurasian distribution, being present in much of the Holarctic region of the northern hemisphere. The family Plethodontidae is also found in Central America and South America north of the Amazon basin;[40] South America was apparently invaded from Central America by about the start of the Miocene, 23 million years ago.[47] Urodela is a name sometimes used for all the extant species of salamanders.[48] Members of several salamander families have become paedomorphic and either fail to complete their metamorphosis or retain some larval characteristics as adults.[49] Most salamanders are under 15 cm (6 in) long. They may be terrestrial or aquatic and many spend part of the year in each habitat. When on land, they mostly spend the day hidden under stones or logs or in dense vegetation, emerging in the evening and night to forage for worms, insects and other invertebrates.[40]
+
+The suborder Cryptobranchoidea contains the primitive salamanders. A number of fossil cryptobranchids have been found, but there are only three living species, the Chinese giant salamander (Andrias davidianus), the Japanese giant salamander (Andrias japonicus) and the hellbender (Cryptobranchus alleganiensis) from North America. These large amphibians retain several larval characteristics in their adult state; gills slits are present and the eyes are unlidded. A unique feature is their ability to feed by suction, depressing either the left side of their lower jaw or the right.[50] The males excavate nests, persuade females to lay their egg strings inside them, and guard them. As well as breathing with lungs, they respire through the many folds in their thin skin, which has capillaries close to the surface.[51]
+
+The suborder Salamandroidea contains the advanced salamanders. They differ from the cryptobranchids by having fused prearticular bones in the lower jaw, and by using internal fertilisation. In salamandrids, the male deposits a bundle of sperm, the spermatophore, and the female picks it up and inserts it into her cloaca where the sperm is stored until the eggs are laid.[52] The largest family in this group is Plethodontidae, the lungless salamanders, which includes 60% of all salamander species. The family Salamandridae includes the true salamanders and the name "newt" is given to members of its subfamily Pleurodelinae.[8]
+
+The third suborder, Sirenoidea, contains the four species of sirens, which are in a single family, Sirenidae. Members of this order are eel-like aquatic salamanders with much reduced forelimbs and no hind limbs. Some of their features are primitive while others are derived.[53] Fertilisation is likely to be external as sirenids lack the cloacal glands used by male salamandrids to produce spermatophores and the females lack spermathecae for sperm storage. Despite this, the eggs are laid singly, a behaviour not conducive for external fertilisation.[52]
+
+The order Gymnophiona (from the Greek gymnos meaning "naked" and ophis meaning "serpent") or Apoda comprises the caecilians. These are long, cylindrical, limbless animals with a snake- or worm-like form. The adults vary in length from 8 to 75 centimetres (3 to 30 inches) with the exception of Thomson's caecilian (Caecilia thompsoni), which can reach 150 centimetres (4.9 feet). A caecilian's skin has a large number of transverse folds and in some species contains tiny embedded dermal scales. It has rudimentary eyes covered in skin, which are probably limited to discerning differences in light intensity. It also has a pair of short tentacles near the eye that can be extended and which have tactile and olfactory functions. Most caecilians live underground in burrows in damp soil, in rotten wood and under plant debris, but some are aquatic.[54] Most species lay their eggs underground and when the larvae hatch, they make their way to adjacent bodies of water. Others brood their eggs and the larvae undergo metamorphosis before the eggs hatch. A few species give birth to live young, nourishing them with glandular secretions while they are in the oviduct.[55] Caecilians have a mostly Gondwanan distribution, being found in tropical regions of Africa, Asia and Central and South America.[56]
+
+The integumentary structure contains some typical characteristics common to terrestrial vertebrates, such as the presence of highly cornified outer layers, renewed periodically through a moulting process controlled by the pituitary and thyroid glands. Local thickenings (often called warts) are common, such as those found on toads. The outside of the skin is shed periodically mostly in one piece, in contrast to mammals and birds where it is shed in flakes. Amphibians often eat the sloughed skin.[40] Caecilians are unique among amphibians in having mineralized dermal scales embedded in the dermis between the furrows in the skin. The similarity of these to the scales of bony fish is largely superficial. Lizards and some frogs have somewhat similar osteoderms forming bony deposits in the dermis, but this is an example of convergent evolution with similar structures having arisen independently in diverse vertebrate lineages.[57]
+
+Amphibian skin is permeable to water. Gas exchange can take place through the skin (cutaneous respiration) and this allows adult amphibians to respire without rising to the surface of water and to hibernate at the bottom of ponds.[40] To compensate for their thin and delicate skin, amphibians have evolved mucous glands, principally on their heads, backs and tails. The secretions produced by these help keep the skin moist. In addition, most species of amphibian have granular glands that secrete distasteful or poisonous substances. Some amphibian toxins can be lethal to humans while others have little effect.[58] The main poison-producing glands, the parotoids, produce the neurotoxin bufotoxin and are located behind the ears of toads, along the backs of frogs, behind the eyes of salamanders and on the upper surface of caecilians.[59]
+
+The skin colour of amphibians is produced by three layers of pigment cells called chromatophores. These three cell layers consist of the melanophores (occupying the deepest layer), the guanophores (forming an intermediate layer and containing many granules, producing a blue-green colour) and the lipophores (yellow, the most superficial layer). The colour change displayed by many species is initiated by hormones secreted by the pituitary gland. Unlike bony fish, there is no direct control of the pigment cells by the nervous system, and this results in the colour change taking place more slowly than happens in fish. A vividly coloured skin usually indicates that the species is toxic and is a warning sign to predators.[60]
+
+Amphibians have a skeletal system that is structurally homologous to other tetrapods, though with a number of variations. They all have four limbs except for the legless caecilians and a few species of salamander with reduced or no limbs. The bones are hollow and lightweight. The musculoskeletal system is strong to enable it to support the head and body. The bones are fully ossified and the vertebrae interlock with each other by means of overlapping processes. The pectoral girdle is supported by muscle, and the well-developed pelvic girdle is attached to the backbone by a pair of sacral ribs. The ilium slopes forward and the body is held closer to the ground than is the case in mammals.[61]
+
+In most amphibians, there are four digits on the fore foot and five on the hind foot, but no claws on either. Some salamanders have fewer digits and the amphiumas are eel-like in appearance with tiny, stubby legs. The sirens are aquatic salamanders with stumpy forelimbs and no hind limbs. The caecilians are limbless. They burrow in the manner of earthworms with zones of muscle contractions moving along the body. On the surface of the ground or in water they move by undulating their body from side to side.[62]
+
+In frogs, the hind legs are larger than the fore legs, especially so in those species that principally move by jumping or swimming. In the walkers and runners the hind limbs are not so large, and the burrowers mostly have short limbs and broad bodies. The feet have adaptations for the way of life, with webbing between the toes for swimming, broad adhesive toe pads for climbing, and keratinised tubercles on the hind feet for digging (frogs usually dig backwards into the soil). In most salamanders, the limbs are short and more or less the same length and project at right angles from the body. Locomotion on land is by walking and the tail often swings from side to side or is used as a prop, particularly when climbing. In their normal gait, only one leg is advanced at a time in the manner adopted by their ancestors, the lobe-finned fish.[61] Some salamanders in the genus Aneides and certain plethodontids climb trees and have long limbs, large toepads and prehensile tails.[52] In aquatic salamanders and in frog tadpoles, the tail has dorsal and ventral fins and is moved from side to side as a means of propulsion. Adult frogs do not have tails and caecilians have only very short ones.[62]
+
+Salamanders use their tails in defence and some are prepared to jettison them to save their lives in a process known as autotomy. Certain species in the Plethodontidae have a weak zone at the base of the tail and use this strategy readily. The tail often continues to twitch after separation which may distract the attacker and allow the salamander to escape. Both tails and limbs can be regenerated.[63] Adult frogs are unable to regrow limbs but tadpoles can do so.[62]
+
+Amphibians have a juvenile stage and an adult stage, and the circulatory systems of the two are distinct. In the juvenile (or tadpole) stage, the circulation is similar to that of a fish; the two-chambered heart pumps the blood through the gills where it is oxygenated, and is spread around the body and back to the heart in a single loop. In the adult stage, amphibians (especially frogs) lose their gills and develop lungs. They have a heart that consists of a single ventricle and two atria. When the ventricle starts contracting, deoxygenated blood is pumped through the pulmonary artery to the lungs. Continued contraction then pumps oxygenated blood around the rest of the body. Mixing of the two bloodstreams is minimized by the anatomy of the chambers.[64]
+
+The nervous system is basically the same as in other vertebrates, with a central brain, a spinal cord, and nerves throughout the body. The amphibian brain is less well developed than that of reptiles, birds and mammals but is similar in morphology and function to that of a fish. It is believed amphibians are capable of perceiving pain.  The brain consists of equal parts, cerebrum, midbrain and cerebellum. Various parts of the cerebrum process sensory input, such as smell in the olfactory lobe and sight in the optic lobe, and it is additionally the centre of behaviour and learning. The cerebellum is the center of muscular coordination and the medulla oblongata controls some organ functions including heartbeat and respiration. The brain sends signals through the spinal cord and nerves to regulate activity in the rest of the body. The pineal body, known to regulate sleep patterns in humans, is thought to produce the hormones involved in hibernation and aestivation in amphibians.[65]
+
+Tadpoles retain the lateral line system of their ancestral fishes, but this is lost in terrestrial adult amphibians. Some caecilians possess electroreceptors that allow them to locate objects around them when submerged in water. The ears are well developed in frogs. There is no external ear, but the large circular eardrum lies on the surface of the head just behind the eye. This vibrates and sound is transmitted through a single bone, the stapes, to the inner ear. Only high-frequency sounds like mating calls are heard in this way, but low-frequency noises can be detected through another mechanism.[61] There is a patch of specialized haircells, called papilla amphibiorum, in the inner ear capable of detecting deeper sounds. Another feature, unique to frogs and salamanders, is the columella-operculum complex adjoining the auditory capsule which is involved in the transmission of both airborne and seismic signals.[66] The ears of salamanders and caecilians are less highly developed than those of frogs as they do not normally communicate with each other through the medium of sound.[67]
+
+The eyes of tadpoles lack lids, but at metamorphosis, the cornea becomes more dome-shaped, the lens becomes flatter, and eyelids and associated glands and ducts develop.[61] The adult eyes are an improvement on invertebrate eyes and were a first step in the development of more advanced vertebrate eyes. They allow colour vision and depth of focus. In the retinas are green rods, which are receptive to a wide range of wavelengths.[67]
+
+Many amphibians catch their prey by flicking out an elongated tongue with a sticky tip and drawing it back into the mouth before seizing the item with their jaws. Some use inertial feeding to help them swallow the prey, repeatedly thrusting their head forward sharply causing the food to move backwards in their mouth by inertia. Most amphibians swallow their prey whole without much chewing so they possess voluminous stomachs. The short oesophagus is lined with cilia that help to move the food to the stomach and mucus produced by glands in the mouth and pharynx eases its passage. The enzyme chitinase produced in the stomach helps digest the chitinous cuticle of arthropod prey.[68]
+
+Amphibians possess a pancreas, liver and gall bladder. The liver is usually large with two lobes. Its size is determined by its function as a glycogen and fat storage unit, and may change with the seasons as these reserves are built or used up. Adipose tissue is another important means of storing energy and this occurs in the abdomen (in internal structures called fat bodies), under the skin and, in some salamanders, in the tail.[69]
+
+There are two kidneys located dorsally, near the roof of the body cavity. Their job is to filter the blood of metabolic waste and transport the urine via ureters to the urinary bladder where it is stored before being passed out periodically through the cloacal vent. Larvae and most aquatic adult amphibians excrete the nitrogen as ammonia in large quantities of dilute urine, while terrestrial species, with a greater need to conserve water, excrete the less toxic product urea. Some tree frogs with limited access to water excrete most of their metabolic waste as uric acid.[70]
+
+The lungs in amphibians are primitive compared to those of amniotes, possessing few internal septa and large alveoli, and consequently having a comparatively slow diffusion rate for oxygen entering the blood. Ventilation is accomplished by buccal pumping.[71] Most amphibians, however, are able to exchange gases with the water or air via their skin. To enable sufficient cutaneous respiration, the surface of their highly vascularised skin must remain moist to allow the oxygen to diffuse at a sufficiently high rate.[68] Because oxygen concentration in the water increases at both low temperatures and high flow rates, aquatic amphibians in these situations can rely primarily on cutaneous respiration, as in the Titicaca water frog and the hellbender salamander. In air, where oxygen is more concentrated, some small species can rely solely on cutaneous gas exchange, most famously the plethodontid salamanders, which have neither lungs nor gills. Many aquatic salamanders and all tadpoles have gills in their larval stage, with some (such as the axolotl) retaining gills as aquatic adults.[68]
+
+For the purpose of reproduction most amphibians require fresh water although some lay their eggs on land and have developed various means of keeping them moist. A few (e.g. Fejervarya raja) can inhabit brackish water, but there are no true marine amphibians.[72] There are reports, however, of particular amphibian populations unexpectedly invading marine waters. Such was the case with the Black Sea invasion of the natural hybrid Pelophylax esculentus reported in 2010.[73]
+
+Several hundred frog species in adaptive radiations (e.g., Eleutherodactylus, the Pacific Platymantis, the Australo-Papuan microhylids, and many other tropical frogs), however, do not need any water for breeding in the wild. They reproduce via direct development, an ecological and evolutionary adaptation that has allowed them to be completely independent from free-standing water. Almost all of these frogs live in wet tropical rainforests and their eggs hatch directly into miniature versions of the adult, passing through the tadpole stage within the egg. Reproductive success of many amphibians is dependent not only on the quantity of rainfall, but the seasonal timing.[74]
+
+In the tropics, many amphibians breed continuously or at any time of year. In temperate regions, breeding is mostly seasonal, usually in the spring, and is triggered by increasing day length, rising temperatures or rainfall. Experiments have shown the importance of temperature, but the trigger event, especially in arid regions, is often a storm. In anurans, males usually arrive at the breeding sites before females and the vocal chorus they produce may stimulate ovulation in females and the endocrine activity of males that are not yet reproductively active.[75]
+
+In caecilians, fertilisation is internal, the male extruding an intromittent organ, the phallodeum, and inserting it into the female cloaca. The paired Müllerian glands inside the male cloaca secrete a fluid which resembles that produced by mammalian prostate glands and which may transport and nourish the sperm. Fertilisation probably takes place in the oviduct.[76]
+
+The majority of salamanders also engage in internal fertilisation. In most of these, the male deposits a spermatophore, a small packet of sperm on top of a gelatinous cone, on the substrate either on land or in the water. The female takes up the sperm packet by grasping it with the lips of the cloaca and pushing it into the vent. The spermatozoa move to the spermatheca in the roof of the cloaca where they remain until ovulation which may be many months later. Courtship rituals and methods of transfer of the spermatophore vary between species. In some, the spermatophore may be placed directly into the female cloaca while in others, the female may be guided to the spermatophore or restrained with an embrace called amplexus. Certain primitive salamanders in the families Sirenidae, Hynobiidae and Cryptobranchidae practice external fertilisation in a similar manner to frogs, with the female laying the eggs in water and the male releasing sperm onto the egg mass.[76]
+
+With a few exceptions, frogs use external fertilisation. The male grasps the female tightly with his forelimbs either behind the arms or in front of the back legs, or in the case of Epipedobates tricolor, around the neck. They remain in amplexus with their cloacae positioned close together while the female lays the eggs and the male covers them with sperm. Roughened nuptial pads on the male's hands aid in retaining grip. Often the male collects and retains the egg mass, forming a sort of basket with the hind feet. An exception is the granular poison frog (Oophaga granulifera) where the male and female place their cloacae in close proximity while facing in opposite directions and then release eggs and sperm simultaneously. The tailed frog (Ascaphus truei) exhibits internal fertilisation. The "tail" is only possessed by the male and is an extension of the cloaca and used to inseminate the female. This frog lives in fast-flowing streams and internal fertilisation prevents the sperm from being washed away before fertilisation occurs.[77] The sperm may be retained in storage tubes attached to the oviduct until the following spring.[78]
+
+Most frogs can be classified as either prolonged or explosive breeders. Typically, prolonged breeders congregate at a breeding site, the males usually arriving first, calling and setting up territories. Other satellite males remain quietly nearby, waiting for their opportunity to take over a territory. The females arrive sporadically, mate selection takes place and eggs are laid. The females depart and territories may change hands. More females appear and in due course, the breeding season comes to an end. Explosive breeders on the other hand are found where temporary pools appear in dry regions after rainfall. These frogs are typically fossorial species that emerge after heavy rains and congregate at a breeding site. They are attracted there by the calling of the first male to find a suitable place, perhaps a pool that forms in the same place each rainy season. The assembled frogs may call in unison and frenzied activity ensues, the males scrambling to mate with the usually smaller number of females.[77]
+
+There is a direct competition between males to win the attention of the females in salamanders and newts, with elaborate courtship displays to keep the female's attention long enough to get her interested in choosing him to mate with.[79] Some species store sperm through long breeding seasons, as the extra time may allow for interactions with rival sperm.[80]
+
+Most amphibians go through metamorphosis, a process of significant morphological change after birth. In typical amphibian development, eggs are laid in water and larvae are adapted to an aquatic lifestyle. Frogs, toads and salamanders all hatch from the egg as larvae with external gills. Metamorphosis in amphibians is regulated by thyroxine concentration in the blood, which stimulates metamorphosis, and prolactin, which counteracts thyroxine's effect. Specific events are dependent on threshold values for different tissues.[81] Because most embryonic development is outside the parental body, it is subject to many adaptations due to specific environmental circumstances. For this reason tadpoles can have horny ridges instead of teeth, whisker-like skin extensions or fins. They also make use of a sensory lateral line organ similar to that of fish. After metamorphosis, these organs become redundant and will be reabsorbed by controlled cell death, called apoptosis. The variety of adaptations to specific environmental circumstances among amphibians is wide, with many discoveries still being made.[82]
+
+The egg of an amphibian is typically surrounded by a transparent gelatinous covering secreted by the oviducts and containing mucoproteins and mucopolysaccharides. This capsule is permeable to water and gases, and swells considerably as it absorbs water. The ovum is at first rigidly held, but in fertilised eggs the innermost layer liquefies and allows the embryo to move freely. This also happens in salamander eggs, even when they are unfertilised. Eggs of some salamanders and frogs contain unicellular green algae. These penetrate the jelly envelope after the eggs are laid and may increase the supply of oxygen to the embryo through photosynthesis. They seem to both speed up the development of the larvae and reduce mortality.[83] Most eggs contain the pigment melanin which raises their temperature through the absorption of light and also protects them against ultraviolet radiation. Caecilians, some plethodontid salamanders and certain frogs lay eggs underground that are unpigmented. In the wood frog (Rana sylvatica), the interior of the globular egg cluster has been found to be up to 6 °C (11 °F) warmer than its surroundings, which is an advantage in its cool northern habitat.[84]
+
+The eggs may be deposited singly or in small groups, or may take the form of spherical egg masses, rafts or long strings. In terrestrial caecilians, the eggs are laid in grape-like clusters in burrows near streams. The amphibious salamander Ensatina attaches its similar clusters by stalks to underwater stems and roots. The greenhouse frog (Eleutherodactylus planirostris) lays eggs in small groups in the soil where they develop in about two weeks directly into juvenile frogs without an intervening larval stage.[85] The tungara frog (Physalaemus pustulosus) builds a floating nest from foam to protect its eggs. First a raft is built, then eggs are laid in the centre, and finally a foam cap is overlaid. The foam has anti-microbial properties. It contains no detergents but is created by whipping up proteins and lectins secreted by the female.[86][87]
+
+The eggs of amphibians are typically laid in water and hatch into free-living larvae that complete their development in water and later transform into either aquatic or terrestrial adults. In many species of frog and in most lungless salamanders (Plethodontidae), direct development takes place, the larvae growing within the eggs and emerging as miniature adults. Many caecilians and some other amphibians lay their eggs on land, and the newly hatched larvae wriggle or are transported to water bodies. Some caecilians, the alpine salamander (Salamandra atra) and some of the African live-bearing toads (Nectophrynoides spp.) are viviparous. Their larvae feed on glandular secretions and develop within the female's oviduct, often for long periods. Other amphibians, but not caecilians, are ovoviviparous. The eggs are retained in or on the parent's body, but the larvae subsist on the yolks of their eggs and receive no nourishment from the adult. The larvae emerge at varying stages of their growth, either before or after metamorphosis, according to their species.[88] The toad genus Nectophrynoides exhibits all of these developmental patterns among its dozen or so members.[6]
+
+Frog larvae are known as tadpoles and typically have oval bodies and long, vertically flattened tails with fins. The free-living larvae are normally fully aquatic, but the tadpoles of some species (such as Nannophrys ceylonensis) are semi-terrestrial and live among wet rocks.[89] Tadpoles have cartilaginous skeletons, gills for respiration (external gills at first, internal gills later), lateral line systems and large tails that they use for swimming.[90] Newly hatched tadpoles soon develop gill pouches that cover the gills. The lungs develop early and are used as accessory breathing organs, the tadpoles rising to the water surface to gulp air. Some species complete their development inside the egg and hatch directly into small frogs. These larvae do not have gills but instead have specialised areas of skin through which respiration takes place. While tadpoles do not have true teeth, in most species, the jaws have long, parallel rows of small keratinized structures called keradonts surrounded by a horny beak.[91] Front legs are formed under the gill sac and hind legs become visible a few days later.
+
+Iodine and T4 (over stimulate the spectacular apoptosis [programmed cell death] of the cells of the larval gills, tail and fins) also stimulate the evolution of nervous systems transforming the aquatic, vegetarian tadpole into the terrestrial, carnivorous frog with better neurological, visuospatial, olfactory and cognitive abilities for hunting.[92][93]
+
+In fact, tadpoles developing in ponds and streams are typically herbivorous. Pond tadpoles tend to have deep bodies, large caudal fins and small mouths; they swim in the quiet waters feeding on growing or loose fragments of vegetation. Stream dwellers mostly have larger mouths, shallow bodies and caudal fins; they attach themselves to plants and stones and feed on the surface films of algae and bacteria.[94] They also feed on diatoms, filtered from the water through the gills, and stir up the sediment at bottom of the pond, ingesting edible fragments. They have a relatively long, spiral-shaped gut to enable them to digest this diet.[94] Some species are carnivorous at the tadpole stage, eating insects, smaller tadpoles and fish. Young of the Cuban tree frog (Osteopilus septentrionalis) can occasionally be cannibalistic, the younger tadpoles attacking a larger, more developed tadpole when it is undergoing metamorphosis.[95]
+
+At metamorphosis, rapid changes in the body take place as the lifestyle of the frog changes completely. The spiral‐shaped mouth with horny tooth ridges is reabsorbed together with the spiral gut. The animal develops a large jaw, and its gills disappear along with its gill sac. Eyes and legs grow quickly, and a tongue is formed. There are associated changes in the neural networks such as development of stereoscopic vision and loss of the lateral line system. All this can happen in about a day. A few days later, the tail is reabsorbed, due to the higher thyroxine concentration required for this to take place.[94]
+
+At hatching, a typical salamander larva has eyes without lids, teeth in both upper and lower jaws, three pairs of feathery external gills, a somewhat laterally flattened body and a long tail with dorsal and ventral fins. The forelimbs may be partially developed and the hind limbs are rudimentary in pond-living species but may be rather more developed in species that reproduce in moving water. Pond-type larvae often have a pair of balancers, rod-like structures on either side of the head that may prevent the gills from becoming clogged up with sediment. Some members of the genera Ambystoma and Dicamptodon have larvae that never fully develop into the adult form, but this varies with species and with populations. The northwestern salamander (Ambystoma gracile) is one of these and, depending on environmental factors, either remains permanently in the larval state, a condition known as neoteny, or transforms into an adult.[96] Both of these are able to breed.[97] Neoteny occurs when the animal's growth rate is very low and is usually linked to adverse conditions such as low water temperatures that may change the response of the tissues to the hormone thyroxine.[98] Other factors that may inhibit metamorphosis include lack of food, lack of trace elements and competition from conspecifics. The tiger salamander (Ambystoma tigrinum) also sometimes behaves in this way and may grow particularly large in the process. The adult tiger salamander is terrestrial, but the larva is aquatic and able to breed while still in the larval state. When conditions are particularly inhospitable on land, larval breeding may allow continuation of a population that would otherwise die out. There are fifteen species of obligate neotenic salamanders, including species of Necturus, Proteus and Amphiuma, and many examples of facultative ones that adopt this strategy under appropriate environmental circumstances.[99]
+
+Lungless salamanders in the family Plethodontidae are terrestrial and lay a small number of unpigmented eggs in a cluster among damp leaf litter. Each egg has a large yolk sac and the larva feeds on this while it develops inside the egg, emerging fully formed as a juvenile salamander. The female salamander often broods the eggs. In the genus Ensatinas, the female has been observed to coil around them and press her throat area against them, effectively massaging them with a mucous secretion.[100]
+
+In newts and salamanders, metamorphosis is less dramatic than in frogs. This is because the larvae are already carnivorous and continue to feed as predators when they are adults so few changes are needed to their digestive systems. Their lungs are functional early, but the larvae do not make as much use of them as do tadpoles. Their gills are never covered by gill sacs and are reabsorbed just before the animals leave the water. Other changes include the reduction in size or loss of tail fins, the closure of gill slits, thickening of the skin, the development of eyelids, and certain changes in dentition and tongue structure. Salamanders are at their most vulnerable at metamorphosis as swimming speeds are reduced and transforming tails are encumbrances on land.[101] Adult salamanders often have an aquatic phase in spring and summer, and a land phase in winter. For adaptation to a water phase, prolactin is the required hormone, and for adaptation to the land phase, thyroxine. External gills do not return in subsequent aquatic phases because these are completely absorbed upon leaving the water for the first time.[102]
+
+Most terrestrial caecilians that lay eggs do so in burrows or moist places on land near bodies of water. The development of the young of Ichthyophis glutinosus, a species from Sri Lanka, has been much studied. The eel-like larvae hatch out of the eggs and make their way to water. They have three pairs of external red feathery gills, a blunt head with two rudimentary eyes, a lateral line system and a short tail with fins. They swim by undulating their body from side to side. They are mostly active at night, soon lose their gills and make sorties onto land. Metamorphosis is gradual. By the age of about ten months they have developed a pointed head with sensory tentacles near the mouth and lost their eyes, lateral line systems and tails. The skin thickens, embedded scales develop and the body divides into segments. By this time, the caecilian has constructed a burrow and is living on land.[103]
+
+In the majority of species of caecilians, the young are produced by viviparity. Typhlonectes compressicauda, a species from South America, is typical of these. Up to nine larvae can develop in the oviduct at any one time. They are elongated and have paired sac-like gills, small eyes and specialised scraping teeth. At first, they feed on the yolks of the eggs, but as this source of nourishment declines they begin to rasp at the ciliated epithelial cells that line the oviduct. This stimulates the secretion of fluids rich in lipids and mucoproteins on which they feed along with scrapings from the oviduct wall. They may increase their length sixfold and be two-fifths as long as their mother before being born. By this time they have undergone metamorphosis, lost their eyes and gills, developed a thicker skin and mouth tentacles, and reabsorbed their teeth. A permanent set of teeth grow through soon after birth.[104][105]
+
+The ringed caecilian (Siphonops annulatus) has developed a unique adaptation for the purposes of reproduction. The progeny feed on a skin layer that is specially developed by the adult in a phenomenon known as maternal dermatophagy. The brood feed as a batch for about seven minutes at intervals of approximately three days which gives the skin an opportunity to regenerate. Meanwhile, they have been observed to ingest fluid exuded from the maternal cloaca.[106]
+
+The care of offspring among amphibians has been little studied but, in general, the larger the number of eggs in a batch, the less likely it is that any degree of parental care takes place. Nevertheless, it is estimated that in up to 20% of amphibian species, one or both adults play some role in the care of the young.[107] Those species that breed in smaller water bodies or other specialised habitats tend to have complex patterns of behaviour in the care of their young.[108]
+
+Many woodland salamanders lay clutches of eggs under dead logs or stones on land. The black mountain salamander (Desmognathus welteri) does this, the mother brooding the eggs and guarding them from predation as the embryos feed on the yolks of their eggs. When fully developed, they break their way out of the egg capsules and disperse as juvenile salamanders.[109] The male hellbender, a primitive salamander, excavates an underwater nest and encourages females to lay there. The male then guards the site for the two or three months before the eggs hatch, using body undulations to fan the eggs and increase their supply of oxygen.[51]
+
+The male Colostethus subpunctatus, a tiny frog, protects the egg cluster which is hidden under a stone or log. When the eggs hatch, the male transports the tadpoles on his back, stuck there by a mucous secretion, to a temporary pool where he dips himself into the water and the tadpoles drop off.[110] The male midwife toad (Alytes obstetricans) winds egg strings round his thighs and carries the eggs around for up to eight weeks. He keeps them moist and when they are ready to hatch, he visits a pond or ditch and releases the tadpoles.[111] The female gastric-brooding frog (Rheobatrachus spp.) reared larvae in her stomach after swallowing either the eggs or hatchlings; however, this stage was never observed before the species became extinct. The tadpoles secrete a hormone that inhibits digestion in the mother whilst they develop by consuming their very large yolk supply.[112] The pouched frog (Assa darlingtoni) lays eggs on the ground. When they hatch, the male carries the tadpoles around in brood pouches on his hind legs.[113] The aquatic Surinam toad (Pipa pipa) raises its young in pores on its back where they remain until metamorphosis.[114] The granular poison frog (Oophaga granulifera) is typical of a number of tree frogs in the poison dart frog family Dendrobatidae. Its eggs are laid on the forest floor and when they hatch, the tadpoles are carried one by one on the back of an adult to a suitable water-filled crevice such as the axil of a leaf or the rosette of a bromeliad. The female visits the nursery sites regularly and deposits unfertilised eggs in the water and these are consumed by the tadpoles.[115]
+
+With a few exceptions, adult amphibians are predators, feeding on virtually anything that moves that they can swallow. The diet mostly consists of small prey that do not move too fast such as beetles, caterpillars, earthworms and spiders. The sirens (Siren spp.) often ingest aquatic plant material with the invertebrates on which they feed[116] and a Brazilian tree frog (Xenohyla truncata) includes a large quantity of fruit in its diet.[117] The Mexican burrowing toad (Rhinophrynus dorsalis) has a specially adapted tongue for picking up ants and termites. It projects it with the tip foremost whereas other frogs flick out the rear part first, their tongues being hinged at the front.[118]
+
+Food is mostly selected by sight, even in conditions of dim light. Movement of the prey triggers a feeding response. Frogs have been caught on fish hooks baited with red flannel and green frogs (Rana clamitans) have been found with stomachs full of elm seeds that they had seen floating past.[119] Toads, salamanders and caecilians also use smell to detect prey. This response is mostly secondary because salamanders have been observed to remain stationary near odoriferous prey but only feed if it moves. Cave-dwelling amphibians normally hunt by smell. Some salamanders seem to have learned to recognize immobile prey when it has no smell, even in complete darkness.[120]
+
+Amphibians usually swallow food whole but may chew it lightly first to subdue it.[40] They typically have small hinged pedicellate teeth, a feature unique to amphibians. The base and crown of these are composed of dentine separated by an uncalcified layer and they are replaced at intervals. Salamanders, caecilians and some frogs have one or two rows of teeth in both jaws, but some frogs (Rana spp.) lack teeth in the lower jaw, and toads (Bufo spp.) have no teeth. In many amphibians there are also vomerine teeth attached to a facial bone in the roof of the mouth.[121]
+
+The tiger salamander (Ambystoma tigrinum) is typical of the frogs and salamanders that hide under cover ready to ambush unwary invertebrates. Others amphibians, such as the Bufo spp. toads, actively search for prey, while the Argentine horned frog (Ceratophrys ornata) lures inquisitive prey closer by raising its hind feet over its back and vibrating its yellow toes.[122] Among leaf litter frogs in Panama, frogs that actively hunt prey have narrow mouths and are slim, often brightly coloured and toxic, while ambushers have wide mouths and are broad and well-camouflaged.[123] Caecilians do not flick their tongues, but catch their prey by grabbing it with their slightly backward-pointing teeth. The struggles of the prey and further jaw movements work it inwards and the caecilian usually retreats into its burrow. The subdued prey is gulped down whole.[124]
+
+When they are newly hatched, frog larvae feed on the yolk of the egg. When this is exhausted some move on to feed on bacteria, algal crusts, detritus and raspings from submerged plants. Water is drawn in through their mouths, which are usually at the bottom of their heads, and passes through branchial food traps between their mouths and their gills where fine particles are trapped in mucus and filtered out. Others have specialised mouthparts consisting of a horny beak edged by several rows of labial teeth. They scrape and bite food of many kinds as well as stirring up the bottom sediment, filtering out larger particles with the papillae around their mouths. Some, such as the spadefoot toads, have strong biting jaws and are carnivorous or even cannibalistic.[125]
+
+The calls made by caecilians and salamanders are limited to occasional soft squeaks, grunts or hisses and have not been much studied. A clicking sound sometimes produced by caecilians may be a means of orientation, as in bats, or a form of communication. Most salamanders are considered voiceless, but the California giant salamander (Dicamptodon ensatus) has vocal cords and can produce a rattling or barking sound. Some species of salamander emit a quiet squeak or yelp if attacked.[126]
+
+Frogs are much more vocal, especially during the breeding season when they use their voices to attract mates. The presence of a particular species in an area may be more easily discerned by its characteristic call than by a fleeting glimpse of the animal itself. In most species, the sound is produced by expelling air from the lungs over the vocal cords into an air sac or sacs in the throat or at the corner of the mouth. This may distend like a balloon and acts as a resonator, helping to transfer the sound to the atmosphere, or the water at times when the animal is submerged.[126] The main vocalisation is the male's loud advertisement call which seeks to both encourage a female to approach and discourage other males from intruding on its territory. This call is modified to a quieter courtship call on the approach of a female or to a more aggressive version if a male intruder draws near. Calling carries the risk of attracting predators and involves the expenditure of much energy.[127] Other calls include those given by a female in response to the advertisement call and a release call given by a male or female during unwanted attempts at amplexus. When a frog is attacked, a distress or fright call is emitted, often resembling a scream.[128] The usually nocturnal Cuban tree frog (Osteopilus septentrionalis) produces a rain call when there is rainfall during daylight hours.[129]
+
+Little is known of the territorial behaviour of caecilians, but some frogs and salamanders defend home ranges. These are usually feeding, breeding or sheltering sites. Males normally exhibit such behaviour though in some species, females and even juveniles are also involved. Although in many frog species, females are larger than males, this is not the case in most species where males are actively involved in territorial defence. Some of these have specific adaptations such as enlarged teeth for biting or spines on the chest, arms or thumbs.[130]
+
+In salamanders, defence of a territory involves adopting an aggressive posture and if necessary attacking the intruder. This may involve snapping, chasing and sometimes biting, occasionally causing the loss of a tail. The behaviour of red back salamanders (Plethodon cinereus) has been much studied. 91% of marked individuals that were later recaptured were within a metre (yard) of their original daytime retreat under a log or rock.[131] A similar proportion, when moved experimentally a distance of 30 metres (98 ft), found their way back to their home base.[131] The salamanders left odour marks around their territories which averaged 0.16 to 0.33 square metres (1.7 to 3.6 sq ft) in size and were sometimes inhabited by a male and female pair.[132] These deterred the intrusion of others and delineated the boundaries between neighbouring areas. Much of their behaviour seemed stereotyped and did not involve any actual contact between individuals. An aggressive posture involved raising the body off the ground and glaring at the opponent who often turned away submissively. If the intruder persisted, a biting lunge was usually launched at either the tail region or the naso-labial grooves. Damage to either of these areas can reduce the fitness of the rival, either because of the need to regenerate tissue or because it impairs its ability to detect food.[131]
+
+In frogs, male territorial behaviour is often observed at breeding locations; calling is both an announcement of ownership of part of this resource and an advertisement call to potential mates. In general, a deeper voice represents a heavier and more powerful individual, and this may be sufficient to prevent intrusion by smaller males. Much energy is used in the vocalization and it takes a toll on the territory holder who may be displaced by a fitter rival if he tires. There is a tendency for males to tolerate the holders of neighbouring territories while vigorously attacking unknown intruders. Holders of territories have a "home advantage" and usually come off better in an encounter between two similar-sized frogs. If threats are insufficient, chest to chest tussles may take place. Fighting methods include pushing and shoving, deflating the opponent's vocal sac, seizing him by the head, jumping on his back, biting, chasing, splashing, and ducking him under the water.[133]
+
+Amphibians have soft bodies with thin skins, and lack claws, defensive armour, or spines. Nevertheless, they have evolved various defence mechanisms to keep themselves alive. The first line of defence in salamanders and frogs is the mucous secretion that they produce. This keeps their skin moist and makes them slippery and difficult to grip. The secretion is often sticky and distasteful or toxic.[134] Snakes have been observed yawning and gaping when trying to swallow African clawed frogs (Xenopus laevis), which gives the frogs an opportunity to escape.[134][135] Caecilians have been little studied in this respect, but the Cayenne caecilian (Typhlonectes compressicauda) produces toxic mucus that has killed predatory fish in a feeding experiment in Brazil.[136] In some salamanders, the skin is poisonous. The rough-skinned newt (Taricha granulosa) from North America and other members of its genus contain the neurotoxin tetrodotoxin (TTX), the most toxic non-protein substance known and almost identical to that produced by pufferfish. Handling the newts does not cause harm, but ingestion of even the most minute amounts of the skin is deadly. In feeding trials, fish, frogs, reptiles, birds and mammals were all found to be susceptible.[137][138] The only predators with some tolerance to the poison are certain populations of common garter snake (Thamnophis sirtalis).
+In locations where both snake and salamander co-exist, the snakes have developed immunity through genetic changes and they feed on the amphibians with impunity.[139] Coevolution occurs with the newt increasing its toxic capabilities at the same rate as the snake further develops its immunity.[138] Some frogs and toads are toxic, the main poison glands being at the side of the neck and under the warts on the back. These regions are presented to the attacking animal and their secretions may be foul-tasting or cause various physical or neurological symptoms. Altogether, over 200 toxins have been isolated from the limited number of amphibian species that have been investigated.[140]
+
+Poisonous species often use bright colouring to warn potential predators of their toxicity. These warning colours tend to be red or yellow combined with black, with the fire salamander (Salamandra salamandra) being an example. Once a predator has sampled one of these, it is likely to remember the colouration next time it encounters a similar animal. In some species, such as the fire-bellied toad (Bombina spp.), the warning colouration is on the belly and these animals adopt a defensive pose when attacked, exhibiting their bright colours to the predator. The frog Allobates zaparo is not poisonous, but mimics the appearance of other toxic species in its locality, a strategy that may deceive predators.[142]
+
+Many amphibians are nocturnal and hide during the day, thereby avoiding diurnal predators that hunt by sight. Other amphibians use camouflage to avoid being detected. They have various colourings such as mottled browns, greys and olives to blend into the background. Some salamanders adopt defensive poses when faced by a potential predator such as the North American northern short-tailed shrew (Blarina brevicauda). Their bodies writhe and they raise and lash their tails which makes it difficult for the predator to avoid contact with their poison-producing granular glands.[143] A few salamanders will autotomise their tails when attacked, sacrificing this part of their anatomy to enable them to escape. The tail may have a constriction at its base to allow it to be easily detached. The tail is regenerated later, but the energy cost to the animal of replacing it is significant.[63]
+Some frogs and toads inflate themselves to make themselves look large and fierce, and some spadefoot toads (Pelobates spp) scream and leap towards the attacker.[40] Giant salamanders of the genus Andrias, as well as Ceratophrine and Pyxicephalus frogs possess sharp teeth and are capable of drawing blood with a defensive bite. The blackbelly salamander (Desmognathus quadramaculatus) can bite an attacking common garter snake (Thamnophis sirtalis) two or three times its size on the head and often manages to escape.[144]
+
+In amphibians, there is evidence of habituation, associative learning through both classical and instrumental learning, and discrimination abilities.[145]
+
+In one experiment, when offered live fruit flies (Drosophila virilis), salamanders chose the larger of 1 vs 2 and 2 vs 3. Frogs can distinguish between low numbers (1 vs 2, 2 vs 3, but not 3 vs 4) and large numbers (3 vs 6, 4 vs 8, but not 4 vs 6) of prey. This is irrespective of other characteristics, i.e. surface area, volume, weight and movement, although discrimination among large numbers may be based on surface area.[146]
+
+Dramatic declines in amphibian populations, including population crashes and mass localized extinction, have been noted since the late 1980s from locations all over the world, and amphibian declines are thus perceived to be one of the most critical threats to global biodiversity.[147] In 2004, the International Union for Conservation of Nature (IUCN) reported stating that currently birds,[148] mammals, and amphibians extinction rates were at minimum 48 times greater than natural extinction rates—possibly 1,024 times higher.
+In 2006 there were believed to be 4,035 species of amphibians that depended on water at some stage during their life cycle. Of these, 1,356 (33.6%) were considered to be threatened and this figure is likely to be an underestimate because it excludes 1,427 species for which there was insufficient data to assess their status.[149] A number of causes are believed to be involved, including habitat destruction and modification, over-exploitation, pollution, introduced species, global warming, endocrine-disrupting pollutants, destruction of the ozone layer (ultraviolet radiation has shown to be especially damaging to the skin, eyes, and eggs of amphibians), and diseases like chytridiomycosis. However, many of the causes of amphibian declines are still poorly understood, and are a topic of ongoing discussion.[150]
+
+With their complex reproductive needs and permeable skins, amphibians are often considered to be ecological indicators.[151] In many terrestrial ecosystems, they constitute one of the largest parts of the vertebrate biomass. Any decline in amphibian numbers will affect the patterns of predation. The loss of carnivorous species near the top of the food chain will upset the delicate ecosystem balance and may cause dramatic increases in opportunistic species. In the Middle East, a growing appetite for eating frog legs and the consequent gathering of them for food was linked to an increase in mosquitoes.[152] Predators that feed on amphibians are affected by their decline. The western terrestrial garter snake (Thamnophis elegans) in California is largely aquatic and depends heavily on two species of frog that are decreasing in numbers, the Yosemite toad (Bufo canorus) and the mountain yellow-legged frog (Rana muscosa), putting the snake's future at risk. If the snake were to become scarce, this would affect birds of prey and other predators that feed on it.[153] Meanwhile, in the ponds and lakes, fewer frogs means fewer tadpoles. These normally play an important role in controlling the growth of algae and also forage on detritus that accumulates as sediment on the bottom. A reduction in the number of tadpoles may lead to an overgrowth of algae, resulting in depletion of oxygen in the water when the algae later die and decompose. Aquatic invertebrates and fish might then die and there would be unpredictable ecological consequences.[154]
+
+A global strategy to stem the crisis was released in 2005 in the form of the Amphibian Conservation Action Plan. Developed by over eighty leading experts in the field, this call to action details what would be required to curtail amphibian declines and extinctions over the following five years and how much this would cost. The Amphibian Specialist Group of the IUCN is spearheading efforts to implement a comprehensive global strategy for amphibian conservation.[155] Amphibian Ark is an organization that was formed to implement the ex-situ conservation recommendations of this plan, and they have been working with zoos and aquaria around the world, encouraging them to create assurance colonies of threatened amphibians.[155] One such project is the Panama Amphibian Rescue and Conservation Project that built on existing conservation efforts in Panama to create a country-wide response to the threat of chytridiomycosis.[156]
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+A fossil (from Classical Latin: fossilis, literally "obtained by digging")[1] is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood, oil, coal, and DNA remnants. The totality of fossils is known as the fossil record.
+
+Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old.[2] The oldest fossils are around 3.48 billion years old[3][4][5] to 4.1 billion years old.[6][7] The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absolute ages of rocks and the fossils they host.
+
+There are many processes that lead to fossilization, including permineralization, casts and molds, authigenic mineralization, replacement and recrystallization, adpression, carbonization, and bioimmuration.
+
+Fossils vary in size from one-micrometre (1 µm) bacteria[8] to dinosaurs and trees, many meters long and weighing many tons. A fossil normally preserves only a portion of the deceased organism, usually that portion that was partially mineralized during life, such as the bones and teeth of vertebrates, or the chitinous or calcareous exoskeletons of invertebrates. Fossils may also consist of the marks left behind by the organism while it was alive, such as animal tracks or feces (coprolites). These types of fossil are called trace fossils or ichnofossils, as opposed to body fossils. Some fossils are biochemical and are called chemofossils or biosignatures.
+
+The process of fossilization varies according to tissue type and external conditions.
+
+Permineralization is a process of fossilization that occurs when an organism is buried. The empty spaces within an organism (spaces filled with liquid or gas during life) become filled with mineral-rich groundwater. Minerals precipitate from the groundwater, occupying the empty spaces. This process can occur in very small spaces, such as within the cell wall of a plant cell. Small scale permineralization can produce very detailed fossils. For permineralization to occur, the organism must become covered by sediment soon after death, otherwise decay commences. The degree to which the remains are decayed when covered determines the later details of the fossil. Some fossils consist only of skeletal remains or teeth; other fossils contain traces of skin, feathers or even soft tissues. This is a form of diagenesis.
+
+
+
+In some cases, the original remains of the organism completely dissolve or are otherwise destroyed. The remaining organism-shaped hole in the rock is called an external mold. If this hole is later filled with other minerals, it is a cast. An endocast, or internal mold, is formed when sediments or minerals fill the internal cavity of an organism, such as the inside of a bivalve or snail or the hollow of a skull.
+
+This is a special form of cast and mold formation. If the chemistry is right, the organism (or fragment of organism) can act as a nucleus for the precipitation of minerals such as siderite, resulting in a nodule forming around it. If this happens rapidly before significant decay to the organic tissue, very fine three-dimensional morphological detail can be preserved. Nodules from the Carboniferous Mazon Creek fossil beds of Illinois, USA, are among the best documented examples of such mineralization.
+
+Replacement occurs when the shell, bone or other tissue is replaced with another mineral. In some cases mineral replacement of the original shell occurs so gradually and at such fine scales that microstructural features are preserved despite the total loss of original material. A shell is said to be recrystallized when the original skeletal compounds are still present but in a different crystal form, as from aragonite to calcite.
+
+Compression fossils, such as those of fossil ferns, are the result of chemical reduction of the complex organic molecules composing the organism's tissues. In this case the fossil consists of original material, albeit in a geochemically altered state. This chemical change is an expression of diagenesis. Often what remains is a carbonaceous film known as a phytoleim, in which case the fossil is known as a compression. Often, however, the phytoleim is lost and all that remains is an impression of the organism in the rock—an impression fossil. In many cases, however, compressions and impressions occur together. For instance, when the rock is broken open, the phytoleim will often be attached to one part (compression), whereas the counterpart will just be an impression. For this reason, one term covers the two modes of preservation: adpression.[9]
+
+Because of their antiquity, an unexpected exception to the alteration of an organism's tissues by chemical reduction of the complex organic molecules during fossilization has been the discovery of soft tissue in dinosaur fossils, including blood vessels, and the isolation of proteins and evidence for DNA fragments.[10][11][12][13] In 2014, Mary Schweitzer and her colleagues reported the presence of iron particles (goethite-aFeO(OH)) associated with soft tissues recovered from dinosaur fossils. Based on various experiments that studied the interaction of iron in haemoglobin with blood vessel tissue they proposed that solution hypoxia coupled with iron chelation enhances the stability and preservation of soft tissue and provides the basis for an explanation for the unforeseen preservation of fossil soft tissues.[14] However, a slightly older study based on eight taxa ranging in time from the Devonian to the Jurassic found that reasonably well-preserved fibrils that probably represent collagen were preserved in all these fossils and that the quality of preservation depended mostly on the arrangement of the collagen fibers, with tight packing favoring good preservation.[15] There seemed to be no correlation between geological age and quality of preservation, within that timeframe.
+
+Fossils that are carbonized or coalified consist of the organic remains which have been reduced primarily to the chemical element carbon. Carbonized fossils consist of a thin film which forms a silhouette of the original organism, and the original organic remains were typically soft tissues. Coalified fossils consist primarily of coal, and the original organic remains were typically woody in composition.
+
+Carbonized fossil of a possible leech from the Silurian Waukesha Biota of Wisconsin.
+
+Partially coalified axis (branch) of a lycopod from the Devonian of Wisconsin.
+
+Bioimmuration occurs when a skeletal organism overgrows or otherwise subsumes another organism, preserving the latter, or an impression of it, within the skeleton.[17] Usually it is a sessile skeletal organism, such as a bryozoan or an oyster, which grows along a substrate, covering other sessile sclerobionts. Sometimes the bioimmured organism is soft-bodied and is then preserved in negative relief as a kind of external mold. There are also cases where an organism settles on top of a living skeletal organism that grows upwards, preserving the settler in its skeleton. Bioimmuration is known in the fossil record from the Ordovician[18] to the Recent.[17]
+
+Paleontology seeks to map out how life evolved across geologic time. A substantial hurdle is the difficulty of working out fossil ages. Beds that preserve fossils typically lack the radioactive elements needed for radiometric dating. This technique is our only means of giving rocks greater than about 50 million years old an absolute age, and can be accurate to within 0.5% or better.[19] Although radiometric dating requires careful laboratory work, its basic principle is simple: the rates at which various radioactive elements decay are known, and so the ratio of the radioactive element to its decay products shows how long ago the radioactive element was incorporated into the rock. Radioactive elements are common only in rocks with a volcanic origin, and so the only fossil-bearing rocks that can be dated radiometrically are volcanic ash layers, which may provide termini for the intervening sediments.[19]
+
+Consequently, palaeontologists rely on stratigraphy to date fossils. Stratigraphy is the science of deciphering the "layer-cake" that is the sedimentary record.[20] Rocks normally form relatively horizontal layers, with each layer younger than the one underneath it. If a fossil is found between two layers whose ages are known, the fossil's age is claimed to lie between the two known ages.[21] Because rock sequences are not continuous, but may be broken up by faults or periods of erosion, it is very difficult to match up rock beds that are not directly adjacent. However, fossils of species that survived for a relatively short time can be used to match isolated rocks: this technique is called biostratigraphy. For instance, the conodont Eoplacognathus pseudoplanus has a short range in the Middle Ordovician period.[22] If rocks of unknown age have traces of E. pseudoplanus, they have a mid-Ordovician age. Such index fossils must be distinctive, be globally distributed and occupy a short time range to be useful. Misleading results are produced if the index fossils are incorrectly dated.[23] Stratigraphy and biostratigraphy can in general provide only relative dating (A was before B), which is often sufficient for studying evolution. However, this is difficult for some time periods, because of the problems involved in matching rocks of the same age across continents.[23] Family-tree relationships also help to narrow down the date when lineages first appeared. For instance, if fossils of B or C date to X million years ago and the calculated "family tree" says A was an ancestor of B and C, then A must have evolved earlier.
+
+It is also possible to estimate how long ago two living clades diverged, in other words approximately how long ago their last common ancestor must have lived, by assuming that DNA mutations accumulate at a constant rate. These "molecular clocks", however, are fallible, and provide only approximate timing: for example, they are not sufficiently precise and reliable for estimating when the groups that feature in the Cambrian explosion first evolved,[24] and estimates produced by different techniques may vary by a factor of two.[25]
+
+Organisms are only rarely preserved as fossils in the best of circumstances, and only a fraction of such fossils have been discovered. This is illustrated by the fact that the number of species known through the fossil record is less than 5% of the number of known living species, suggesting that the number of species known through fossils must be far less than 1% of all the species that have ever lived.[26] Because of the specialized and rare circumstances required for a biological structure to fossilize, only a small percentage of life-forms can be expected to be represented in discoveries, and each discovery represents only a snapshot of the process of evolution. The transition itself can only be illustrated and corroborated by transitional fossils, which will never demonstrate an exact half-way point.[27]
+
+The fossil record is strongly biased toward organisms with hard-parts, leaving most groups of soft-bodied organisms with little to no role.[26] It is replete with the mollusks, the vertebrates, the echinoderms, the brachiopods and some groups of arthropods.[28]
+
+Fossil sites with exceptional preservation—sometimes including preserved soft tissues—are known as Lagerstätten—German for "storage places". These formations may have resulted from carcass burial in an anoxic environment with minimal bacteria, thus slowing decomposition. Lagerstätten span geological time from the Cambrian period to the present. Worldwide, some of the best examples of near-perfect fossilization are the Cambrian Maotianshan shales and Burgess Shale, the Devonian Hunsrück Slates, the Jurassic Solnhofen limestone, and the Carboniferous Mazon Creek localities.
+
+Stromatolites are layered accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains by biofilms of microorganisms, especially cyanobacteria.[29] Stromatolites provide some of the most ancient fossil records of life on Earth, dating back more than 3.5 billion years ago.[30]
+
+Stromatolites were much more abundant in Precambrian times. While older, Archean fossil remains are presumed to be colonies of cyanobacteria, younger (that is, Proterozoic) fossils may be primordial forms of the eukaryote chlorophytes (that is, green algae). One genus of stromatolite very common in the geologic record is Collenia. The earliest stromatolite of confirmed microbial origin dates to 2.724 billion years ago.[31]
+
+A 2009 discovery provides strong evidence of microbial stromatolites extending as far back as 3.45 billion years ago.[32][33]
+
+Stromatolites are a major constituent of the fossil record for life's first 3.5 billion years, peaking about 1.25 billion years ago.[32] They subsequently declined in abundance and diversity,[34] which by the start of the Cambrian had fallen to 20% of their peak. The most widely supported explanation is that stromatolite builders fell victims to grazing creatures (the Cambrian substrate revolution), implying that sufficiently complex organisms were common over 1 billion years ago.[35][36][37]
+
+The connection between grazer and stromatolite abundance is well documented in the younger Ordovician evolutionary radiation; stromatolite abundance also increased after the end-Ordovician and end-Permian extinctions decimated marine animals, falling back to earlier levels as marine animals recovered.[38] Fluctuations in metazoan population and diversity may not have been the only factor in the reduction in stromatolite abundance. Factors such as the chemistry of the environment may have been responsible for changes.[39]
+
+While prokaryotic cyanobacteria themselves reproduce asexually through cell division, they were instrumental in priming the environment for the evolutionary development of more complex eukaryotic organisms. Cyanobacteria (as well as extremophile Gammaproteobacteria) are thought to be largely responsible for increasing the amount of oxygen in the primeval earth's atmosphere through their continuing photosynthesis. Cyanobacteria use water, carbon dioxide and sunlight to create their food. A layer of mucus often forms over mats of cyanobacterial cells. In modern microbial mats, debris from the surrounding habitat can become trapped within the mucus, which can be cemented by the calcium carbonate to grow thin laminations of limestone. These laminations can accrete over time, resulting in the banded pattern common to stromatolites. The domal morphology of biological stromatolites is the result of the vertical growth necessary for the continued infiltration of sunlight to the organisms for photosynthesis. Layered spherical growth structures termed oncolites are similar to stromatolites and are also known from the fossil record. Thrombolites are poorly laminated or non-laminated clotted structures formed by cyanobacteria common in the fossil record and in modern sediments.[31]
+
+The Zebra River Canyon area of the Kubis platform in the deeply dissected Zaris Mountains of southwestern Namibia provides an extremely well exposed example of the thrombolite-stromatolite-metazoan reefs that developed during the Proterozoic period, the stromatolites here being better developed in updip locations under conditions of higher current velocities and greater sediment influx.[40]
+
+Index fossils (also known as guide fossils, indicator fossils or zone fossils) are fossils used to define and identify geologic periods (or faunal stages). They work on the premise that, although different sediments may look different depending on the conditions under which they were deposited, they may include the remains of the same species of fossil. The shorter the species' time range, the more precisely different sediments can be correlated, and so rapidly evolving species' fossils are particularly valuable. The best index fossils are common, easy to identify at species level and have a broad distribution—otherwise the likelihood of finding and recognizing one in the two sediments is poor.
+
+Trace fossils consist mainly of tracks and burrows, but also include coprolites (fossil feces) and marks left by feeding.[41][42] Trace fossils are particularly significant because they represent a data source that is not limited to animals with easily fossilized hard parts, and they reflect animal behaviours. Many traces date from significantly earlier than the body fossils of animals that are thought to have been capable of making them.[43] Whilst exact assignment of trace fossils to their makers is generally impossible, traces may for example provide the earliest physical evidence of the appearance of moderately complex animals (comparable to earthworms).[42]
+
+Coprolites are classified as trace fossils as opposed to body fossils, as they give evidence for the animal's behaviour (in this case, diet) rather than morphology. They were first described by William Buckland in 1829. Prior to this they were known as "fossil fir cones" and "bezoar stones." They serve a valuable purpose in paleontology because they provide direct evidence of the predation and diet of extinct organisms.[44] Coprolites may range in size from a few millimetres to over 60 centimetres.
+
+Cambrian trace fossils including Rusophycus, made by a trilobite
+
+A coprolite of a carnivorous dinosaur found in southwestern Saskatchewan
+
+Densely packed, subaerial or nearshore trackways (Climactichnites wilsoni) made by a putative, slug-like mollusk on a Cambrian tidal flat
+
+A transitional fossil is any fossilized remains of a life form that exhibits traits common to both an ancestral group and its derived descendant group.[45] This is especially important where the descendant group is sharply differentiated by gross anatomy and mode of living from the ancestral group. Because of the incompleteness of the fossil record, there is usually no way to know exactly how close a transitional fossil is to the point of divergence. These fossils serve as a reminder that taxonomic divisions are human constructs that have been imposed in hindsight on a continuum of variation.
+
+Microfossil is a descriptive term applied to fossilized plants and animals whose size is just at or below the level at which the fossil can be analyzed by the naked eye. A commonly applied cutoff point between "micro" and "macro" fossils is 1 mm. Microfossils may either be complete (or near-complete) organisms in themselves (such as the marine plankters foraminifera and coccolithophores) or component parts (such as small teeth or spores) of larger animals or plants. Microfossils are of critical importance as a reservoir of paleoclimate information, and are also commonly used by biostratigraphers to assist in the correlation of rock units.
+
+Fossil resin (colloquially called amber) is a natural polymer found in many types of strata throughout the world, even the Arctic. The oldest fossil resin dates to the Triassic, though most dates to the Cenozoic. The excretion of the resin by certain plants is thought to be an evolutionary adaptation for protection from insects and to seal wounds. Fossil resin often contains other fossils called inclusions that were captured by the sticky resin. These include bacteria, fungi, other plants, and animals. Animal inclusions are usually small invertebrates, predominantly arthropods such as insects and spiders, and only extremely rarely a vertebrate such as a small lizard. Preservation of inclusions can be exquisite, including small fragments of DNA.
+
+A derived, reworked or remanié fossil is a fossil found in rock that accumulated significantly later than when the fossilized animal or plant died.[46] Reworked fossils are created by erosion exhuming (freeing) fossils from the rock formation in which they were originally deposited and their redeposition in a younger sedimentary deposit.
+
+Fossil wood is wood that is preserved in the fossil record. Wood is usually the part of a plant that is best preserved (and most easily found). Fossil wood may or may not be petrified. The fossil wood may be the only part of the plant that has been preserved:[47] therefore such wood may get a special kind of botanical name. This will usually include "xylon" and a term indicating its presumed affinity, such as Araucarioxylon (wood of Araucaria or some related genus), Palmoxylon (wood of an indeterminate palm), or Castanoxylon (wood of an indeterminate chinkapin).[48]
+
+The term subfossil can be used to refer to remains, such as bones, nests, or defecations, whose fossilization process is not complete, either because the length of time since the animal involved was living is too short (less than 10,000 years) or because the conditions in which the remains were buried were not optimal for fossilization. Subfossils are often found in caves or other shelters where they can be preserved for thousands of years.[49] The main importance of subfossil vs. fossil remains is that the former contain organic material, which can be used for radiocarbon dating or extraction and sequencing of DNA, protein, or other biomolecules. Additionally, isotope ratios can provide much information about the ecological conditions under which extinct animals lived. Subfossils are useful for studying the evolutionary history of an environment and can be important to studies in paleoclimatology.
+
+Subfossils are often found in depositionary environments, such as lake sediments, oceanic sediments, and soils. Once deposited, physical and chemical weathering can alter the state of preservation.
+
+Chemical fossils, or chemofossils, are chemicals found in rocks and fossil fuels (petroleum, coal, and natural gas) that provide an organic signature for ancient life. Molecular fossils and isotope ratios represent two types of chemical fossils.[50] The oldest traces of life on Earth are fossils of this type, including carbon isotope anomalies found in zircons that imply the existence of life as early as 4.1 billion years ago.[6][7]
+
+It has been suggested that biominerals could be important indicators of extraterrestrial life and thus could play an important role in the search for past or present life on the planet Mars. Furthermore, organic components (biosignatures) that are often associated with biominerals are believed to play crucial roles in both pre-biotic and biotic reactions.[51]
+
+On 24 January 2014, NASA reported that current studies by the Curiosity and Opportunity rovers on Mars will now be searching for evidence of ancient life, including a biosphere based on autotrophic, chemotrophic and/or chemolithoautotrophic microorganisms, as well as ancient water, including fluvio-lacustrine environments (plains related to ancient rivers or lakes) that may have been habitable.[52][53][54][55] The search for evidence of habitability, taphonomy (related to fossils), and organic carbon on the planet Mars is now a primary NASA objective.[52][53]
+
+Pseudofossils are visual patterns in rocks that are produced by geologic processes rather than biologic processes. They can easily be mistaken for real fossils. Some pseudofossils, such as geological dendrite crystals, are formed by naturally occurring fissures in the rock that get filled up by percolating minerals. Other types of pseudofossils are kidney ore (round shapes in iron ore) and moss agates, which look like moss or plant leaves. Concretions, spherical or ovoid-shaped nodules found in some sedimentary strata, were once thought to be dinosaur eggs, and are often mistaken for fossils as well.
+
+Gathering fossils dates at least to the beginning of recorded history. The fossils themselves are referred to as the fossil record. The fossil record was one of the early sources of data underlying the study of evolution and continues to be relevant to the history of life on Earth. Paleontologists examine the fossil record to understand the process of evolution and the way particular species have evolved.
+
+Fossils have been visible and common throughout most of natural history, and so documented human interaction with them goes back as far as recorded history, or earlier.
+
+There are many examples of paleolithic stone knives in Europe, with fossil echinoderms set precisely at the hand grip, going all the way back to Homo heidelbergensis and neanderthals.[56] These ancient peoples also drilled holes through the center of those round fossil shells, apparently using them as beads for necklaces.
+
+The ancient Egyptians gathered fossils of species that resembled the bones of modern species they worshipped. The god Set was associated with the hippopotamus, therefore fossilized bones of hippo-like species were kept in that deity's temples.[57] Five-rayed fossil sea urchin shells were associated with the deity Sopdu, the Morning Star, equivalent of Venus in Roman mythology.[56]
+
+Fossils appear to have directly contributed to the mythology of many civilizations, including the ancient Greeks. Classical Greek historian Herodotos wrote of an area near Hyperborea where gryphons protected golden treasure. There was indeed gold mining in that approximate region, where beaked Protoceratops skulls were common as fossils.
+
+A later Greek scholar, Aristotle, eventually realized that fossil seashells from rocks were similar to those found on the beach, indicating the fossils were once living animals. He had previously explained them in terms of vaporous exhalations,[58] which Persian polymath Avicenna modified into the theory of petrifying fluids (succus lapidificatus). This was built upon in the 14th century by Albert of Saxony, and accepted in some form by most naturalists by the 16th century.[59]
+
+Roman naturalist Pliny the Elder wrote of "tongue stones", which he called glossopetra. These were fossil shark teeth, thought by some classical cultures to look like the tongues of people or snakes.[60] He also wrote about the horns of Ammon, which are fossil ammonites, from whence the species ultimately draws its modern name. Pliny also makes one of the earlier known references to toadstones, thought until the 18th century to be a magical cure for poison originating in the heads of toads, but which are fossil teeth from Lepidotes, a Cretaceous ray-finned fish.[61]
+
+The Plains tribes of North America are thought to have similarly associated fossils, such as the many intact pterosaur fossils naturally exposed in the region, with their own mythology of the thunderbird.[62]
+
+There is no such direct mythological connection known from prehistoric Africa, but there is considerable evidence of tribes there excavating and moving fossils to ceremonial sites, apparently treating them with some reverence.[63]
+
+In Japan, fossil shark teeth were associated with the mythical tengu, thought to be the razor-sharp claws of the creature, documented some time after the 8th century AD.[60]
+
+In medieval China, the fossil bones of ancient mammals including Homo erectus were often mistaken for "dragon bones" and used as medicine and aphrodisiacs. In addition, some of these fossil bones are collected as "art" by scholars, who left scripts on various artifacts, indicating the time they were added to a collection. One good example is the famous scholar Huang Tingjian of the South Song Dynasty during the 11th century, who kept a specific seashell fossil with his own poem engraved on it.[64] In the West fossilized sea creatures on mountainsides were seen as proof of the biblical deluge.
+
+In 1027, the Persian Avicenna explained fossils' stoniness in The Book of Healing:
+
+If what is said concerning the petrifaction of animals and plants is true, the cause of this (phenomenon) is a powerful mineralizing and petrifying virtue which arises in certain stony spots, or emanates suddenly from the earth during earthquake and subsidences, and petrifies whatever comes into contact with it. As a matter of fact, the petrifaction of the bodies of plants and animals is not more extraordinary than the transformation of waters.[65]
+
+From the 13th century to the present day, scholars pointed out that the fossil skulls of Deinotherium giganteum, found in Crete and Greece, might have been interpreted as being the skulls of the Cyclopes of Greek mythology, and are possibly the origin of that Greek myth.[66][67] Their skulls appear to have a single eye-hole in the front, just like their modern elephant cousins, though in fact it's actually the opening for their trunk.
+
+In Norse mythology, echinoderm shells (the round five-part button left over from a sea urchin) were associated with the god Thor, not only being incorporated in thunderstones, representations of Thor's hammer and subsequent hammer-shaped crosses as Christianity was adopted, but also kept in houses to garner Thor's protection.[56]
+
+These grew into the shepherd's crowns of English folklore, used for decoration and as good luck charms, placed by the doorway of homes and churches.[68] In Suffolk, a different species was used as a good-luck charm by bakers, who referred to them as fairy loaves, associating them with the similarly shaped loaves of bread they baked.[69][70]
+
+More scientific views of fossils emerged during the Renaissance. Leonardo da Vinci concurred with Aristotle's view that fossils were the remains of ancient life.[71] For example, da Vinci noticed discrepancies with the biblical flood narrative as an explanation for fossil origins:
+
+If the Deluge had carried the shells for distances of three and four hundred miles from the sea it would have carried them mixed with various other natural objects all heaped up together; but even at such distances from the sea we see the oysters all together and also the shellfish and the cuttlefish and all the other shells which congregate together, found all together dead; and the solitary shells are found apart from one another as we see them every day on the sea-shores.
+
+And we find oysters together in very large families, among which some may be seen with their shells still joined together, indicating that they were left there by the sea and that they were still living when the strait of Gibraltar was cut through. In the mountains of Parma and Piacenza multitudes of shells and corals with holes may be seen still sticking to the rocks...."[72]
+
+In 1666, Nicholas Steno examined a shark, and made the association of its teeth with the "tongue stones" of ancient Greco-Roman mythology, concluding that those were not in fact the tongues of venomous snakes, but the teeth of some long-extinct species of shark.[60]
+
+Robert Hooke (1635-1703) included micrographs of fossils in his Micrographia and was among the first to observe fossil forams. His observations on fossils, which he stated to be the petrified remains of creatures some of which no longer existed, were published posthumously in 1705.[73]
+
+William Smith (1769–1839), an English canal engineer, observed that rocks of different ages (based on the law of superposition) preserved different assemblages of fossils, and that these assemblages succeeded one another in a regular and determinable order. He observed that rocks from distant locations could be correlated based on the fossils they contained. He termed this the principle of faunal succession. This principle became one of Darwin's chief pieces of evidence that biological evolution was real.
+
+Georges Cuvier came to believe that most if not all the animal fossils he examined were remains of extinct species. This led Cuvier to become an active proponent of the geological school of thought called catastrophism. Near the end of his 1796 paper on living and fossil elephants he said:
+
+All of these facts, consistent among themselves, and not opposed by any report, seem to me to prove the existence of a world previous to ours, destroyed by some kind of catastrophe.[74]
+
+Interest in fossils, and geology more generally, expanded during the early nineteenth century.  In Britain, Mary Anning's discoveries of fossils, including the first complete ichthyosaur and a complete plesiosaurus skeleton, sparked both public and scholarly interest.[75]
+
+Early naturalists well understood the similarities and differences of living species leading Linnaeus to develop a hierarchical classification system still in use today. Darwin and his contemporaries first linked the hierarchical structure of the tree of life with the then very sparse fossil record. Darwin eloquently described a process of descent with modification, or evolution, whereby organisms either adapt to natural and changing environmental pressures, or they perish.
+
+When Darwin wrote On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, the oldest animal fossils were those from the Cambrian Period, now known to be about 540 million years old. He worried about the absence of older fossils because of the implications on the validity of his theories, but he expressed hope that such fossils would be found, noting that: "only a small portion of the world is known with accuracy." Darwin also pondered the sudden appearance of many groups (i.e. phyla) in the oldest known Cambrian fossiliferous strata.[76]
+
+Since Darwin's time, the fossil record has been extended to between 2.3 and 3.5 billion years.[77] Most of these Precambrian fossils are microscopic bacteria or microfossils. However, macroscopic fossils are now known from the late Proterozoic. The Ediacara biota (also called Vendian biota) dating from 575 million years ago collectively constitutes a richly diverse assembly of early multicellular eukaryotes.
+
+The fossil record and faunal succession form the basis of the science of biostratigraphy or determining the age of rocks based on embedded fossils. For the first 150 years of geology, biostratigraphy and superposition were the only means for determining the relative age of rocks. The geologic time scale was developed based on the relative ages of rock strata as determined by the early paleontologists and stratigraphers.
+
+Since the early years of the twentieth century, absolute dating methods, such as radiometric dating (including potassium/argon, argon/argon, uranium series, and, for very recent fossils, radiocarbon dating) have been used to verify the relative ages obtained by fossils and to provide absolute ages for many fossils. Radiometric dating has shown that the earliest known stromatolites are over 3.4 billion years old.
+
+The Virtual Fossil Museum[78]
+
+Paleontology has joined with evolutionary biology to share the interdisciplinary task of outlining the tree of life, which inevitably leads backwards in time to Precambrian microscopic life when cell structure and functions evolved. Earth's deep time in the Proterozoic and deeper still in the Archean is only "recounted by microscopic fossils and subtle chemical signals."[79] Molecular biologists, using phylogenetics, can compare protein amino acid or nucleotide sequence homology (i.e., similarity) to evaluate taxonomy and evolutionary distances among organisms, with limited statistical confidence. The study of fossils, on the other hand, can more specifically pinpoint when and in what organism a mutation first appeared. Phylogenetics and paleontology work together in the clarification of science's still dim view of the appearance of life and its evolution.[80]
+
+Niles Eldredge's study of the Phacops trilobite genus supported the hypothesis that modifications to the arrangement of the trilobite's eye lenses proceeded by fits and starts over millions of years during the Devonian.[81] Eldredge's interpretation of the Phacops fossil record was that the aftermaths of the lens changes, but not the rapidly occurring evolutionary process, were fossilized. This and other data led Stephen Jay Gould and Niles Eldredge to publish their seminal paper on punctuated equilibrium in 1971.
+
+Synchrotron X-ray tomographic analysis of early Cambrian bilaterian embryonic microfossils yielded new insights of metazoan evolution at its earliest stages. The tomography technique provides previously unattainable three-dimensional resolution at the limits of fossilization. Fossils of two enigmatic bilaterians, the worm-like Markuelia and a putative, primitive protostome, Pseudooides, provide a peek at germ layer embryonic development. These 543-million-year-old embryos support the emergence of some aspects of arthropod development earlier than previously thought in the late Proterozoic. The preserved embryos from China and Siberia underwent rapid diagenetic phosphatization resulting in exquisite preservation, including cell structures. This research is a notable example of how knowledge encoded by the fossil record continues to contribute otherwise unattainable information on the emergence and development of life on Earth. For example, the research suggests Markuelia has closest affinity to priapulid worms, and is adjacent to the evolutionary branching of Priapulida, Nematoda and Arthropoda.[82]
+
+Fossil trading is the practice of buying and selling fossils. This is many times done illegally with artifacts stolen from research sites, costing many important scientific specimens each year.[83] The problem is quite pronounced in China, where many specimens have been stolen.[84]
+
+Fossil collecting (sometimes, in a non-scientific sense, fossil hunting) is the collection of fossils for scientific study, hobby, or profit. Fossil collecting, as practiced by amateurs, is the predecessor of modern paleontology and many still collect fossils and study fossils as amateurs. Professionals and amateurs alike collect fossils for their scientific value.
+
+These is some medicinal and preventive use for some fossils. Largely the use of fossils as medicine is a matter of placebo effect. However, the consumption of certain fossils has been proven to help against stomach acidity and mineral depletion. The use of fossils to address health issues is rooted in traditional medicine and include the use of fossils as talismans. The specific fossil to use to alleviate or cure an illness is often based on its resemblance of the fossils and the symptoms or affected organ.[85] The use dinosaur bones as "dragon bones" has persisted in Traditional Chinese medicine into modern times, with Mid Cretaceous dinosaur bones being used for the purpose in Ruyang County during the early 21st century.[86]
+
+Three small ammonite fossils, each approximately 1.5 cm across
+
+Eocene fossil fish Priscacara liops from the Green River Formation of Wyoming
+
+A permineralized trilobite, Asaphus kowalewskii
+
+Megalodon and Carcharodontosaurus teeth. The latter was found in the Sahara Desert.
+
+Fossil shrimp (Cretaceous)
+
+Petrified wood in Petrified Forest National Park, Arizona
+
+Petrified cone of Araucaria mirabilis from Patagonia, Argentina dating from the Jurassic Period (approx. 210 Ma)
+
+A fossil gastropod from the Pliocene of Cyprus. A serpulid worm is attached.
+
+Silurian Orthoceras fossil
+
+Eocene fossil flower from Florissant, Colorado
+
+Micraster echinoid fossil from England
+
+Productid brachiopod ventral valve; Roadian, Guadalupian (Middle Permian); Glass Mountains, Texas.
+
+Agatized coral from the Hawthorn Group (Oligocene–Miocene), Florida. An example of preservation by replacement.
+
+Fossils from beaches of the Baltic Sea island of Gotland, placed on paper with 7 mm (0.28 inch) squares
+
+Dinosaur footprints from Torotoro National Park in Bolivia.

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+Lightning is a naturally occurring electrostatic discharge during which two electrically charged regions in the atmosphere or ground temporarily equalize themselves, causing the instantaneous release of as much as one gigajoule of energy.[1][2][3] This discharge may produce a wide range of electromagnetic radiation, from very hot plasma created by the rapid movement of electrons to brilliant flashes of visible light in the form of black-body radiation. Lightning causes thunder, a sound from the shock wave which develops as gases in the vicinity of the discharge experience a sudden increase in pressure. Lightning occurs commonly during thunderstorms and other types of energetic weather systems, but volcanic lightning can also occur during volcanic eruptions.
+
+The three main kinds of lightning are distinguished by where they occur: either inside a single thundercloud, between two different clouds, or between a cloud and the ground. Many other observational variants are recognized, including "heat lightning", which can be seen from a great distance but not heard; dry lightning, which can cause forest fires; and ball lightning, which is rarely observed scientifically.
+
+Humans have deified lightning for millennia. Idiomatic expressions derived from lightning, such as the English expression "bolt from the blue", are common across languages.
+
+The details of the charging process are still being studied by scientists, but there is general agreement on some of the basic concepts of thunderstorm electrification. The main charging area in a thunderstorm occurs in the central part of the storm where air is moving upward rapidly (updraft) and temperatures range from −15 to −25 °C (5 to −13 °F); see Figure 1. In that area, the combination of temperature and rapid upward air movement produces a mixture of super-cooled cloud droplets (small water droplets below freezing), small ice crystals, and graupel (soft hail). The updraft carries the super-cooled cloud droplets and very small ice crystals upward. At the same time, the graupel, which is considerably larger and denser, tends to fall or be suspended in the rising air.[4]
+
+The differences in the movement of the precipitation cause collisions to occur. When the rising ice crystals collide with graupel, the ice crystals become positively charged and the graupel becomes negatively charged; see Figure 2. The updraft carries the positively charged ice crystals upward toward the top of the storm cloud. The larger and denser graupel is either suspended in the middle of the thunderstorm cloud or falls toward the lower part of the storm.[4]
+
+The result is that the upper part of the thunderstorm cloud becomes positively charged while the middle to lower part of the thunderstorm cloud becomes negatively charged.[4]
+
+The upward motions within the storm and winds at higher levels in the atmosphere tend to cause the small ice crystals (and positive charge) in the upper part of the thunderstorm cloud to spread out horizontally some distance from the thunderstorm cloud base. This part of the thunderstorm cloud is called the anvil. While this is the main charging process for the thunderstorm cloud, some of these charges can be redistributed by air movements within the storm (updrafts and downdrafts). In addition, there is a small but important positive charge buildup near the bottom of the thunderstorm cloud due to the precipitation and warmer temperatures.[4]
+
+A typical cloud-to-ground lightning flash culminates in the formation of an electrically conducting plasma channel through the air in excess of 5 km (3.1 mi) tall, from within the cloud to the ground's surface. The actual discharge is the final stage of a very complex process.[5] At its peak, a typical thunderstorm produces three or more strikes to the Earth per minute.[6] Lightning primarily occurs when warm air is mixed with colder air masses,[7] resulting in atmospheric disturbances necessary for polarizing the atmosphere.[citation needed] However, it can also occur during dust storms, forest fires, tornadoes, volcanic eruptions, and even in the cold of winter, where the lightning is known as thundersnow.[8][9] Hurricanes typically generate some lightning, mainly in the rainbands as much as 160 km (99 mi) from the center.[10][11][12]
+
+The science of lightning is called fulminology, and the fear of lightning is called astraphobia.
+
+Lightning is not distributed evenly around Earth, as shown in the map.
+
+On Earth, the lightning frequency is approximately 44 (± 5) times per second, or nearly 1.4 billion flashes per year[13] and the average duration is 0.2 seconds made up from a number of much shorter flashes (strokes) of around 60 to 70 microseconds.[14]
+
+Many factors affect the frequency, distribution, strength and physical properties of a typical lightning flash in a particular region of the world. These factors include ground elevation, latitude, prevailing wind currents, relative humidity, proximity to warm and cold bodies of water, etc. To a certain degree, the ratio between IC (in-cloud or intracloud), CC (cloud-to-cloud) and CG (cloud-to-ground) lightning may also vary by season in middle latitudes.
+
+Because human beings are terrestrial and most of their possessions are on the Earth where lightning can damage or destroy them, CG lightning is the most studied and best understood of the three types, even though IC and CC are more common types of lightning. Lightning's relative unpredictability limits a complete explanation of how or why it occurs, even after hundreds of years of scientific investigation.
+About 70% of lightning occurs over land in the tropics[15] where atmospheric convection is the greatest.
+
+This occurs from both the mixture of warmer and colder air masses, as well as differences in moisture concentrations, and it generally happens at the boundaries between them. The flow of warm ocean currents past drier land masses, such as the Gulf Stream, partially explains the elevated frequency of lightning in the Southeast United States. Because large bodies of water lack the topographic variation that would result in atmospheric mixing, lightning is notably less frequent over the world's oceans than over land. The North and South Poles are limited in their coverage of thunderstorms and therefore result in areas with the least amount of lightning.[clarification needed]
+
+In general, cloud-to-ground (CG) lightning flashes account for only 25% of all total lightning flashes worldwide. Since the base of a thunderstorm is usually negatively charged, this is where most CG lightning originates. This region is typically at the elevation where freezing occurs within the cloud. Freezing, combined with collisions between ice and water, appears to be a critical part of the initial charge development and separation process. During wind-driven collisions, ice crystals tend to develop a positive charge, while a heavier, slushy mixture of ice and water (called graupel) develops a negative charge. Updrafts within a storm cloud separate the lighter ice crystals from the heavier graupel, causing the top region of the cloud to accumulate a positive space charge while the lower level accumulates a negative space charge.
+
+Because the concentrated charge within the cloud must exceed the insulating properties of air, and this increases proportionally to the distance between the cloud and the ground, the proportion of CG strikes (versus cloud-to-cloud (CC) or in-cloud (IC) discharges) becomes greater when the cloud is closer to the ground. In the tropics, where the freezing level is generally higher in the atmosphere, only 10% of lightning flashes are CG. At the latitude of Norway (around 60° North latitude), where the freezing elevation is lower, 50% of lightning is CG.[16][17]
+
+Lightning is usually produced by cumulonimbus clouds, which have bases that are typically 1–2 km (0.62–1.24 mi) above the ground and tops up to 15 km (9.3 mi) in height.
+
+The place on Earth where lightning occurs most often is near the small village of Kifuka in the mountains of the eastern Democratic Republic of the Congo,[18] where the elevation is around 975 m (3,200 ft). On average, this region receives 158 lightning strikes per square kilometre per year (410/sq mi/yr).[19] Lake Maracaibo in Venezuela averages 297 days per year with lightning activity, an effect recognized as Catatumbo lightning.[20] Other lightning hotspots Singapore[21] and Lightning Alley in Central Florida.[22][23]
+
+In order for an electrostatic discharge to occur, two preconditions are necessary: firstly, a sufficiently high potential difference between two regions of space must exist, and secondly, a high-resistance medium must obstruct the free, unimpeded equalization of the opposite charges. The atmosphere provides the electrical insulation, or barrier, that prevents free equalization between charged regions of opposite polarity.
+
+It is well understood that during a thunderstorm there is charge separation and aggregation in certain regions of the cloud; however, the exact processes by which this occurs are not fully understood.[24]
+
+As a thundercloud moves over the surface of the Earth, an equal electric charge, but of opposite polarity, is induced on the Earth's surface underneath the cloud. This is known as an image charge. The induced positive surface charge, when measured against a fixed point, will be small as the thundercloud approaches, increasing as the center of the storm arrives and dropping as the thundercloud passes. The referential value of the induced surface charge could be roughly represented as a bell curve.
+
+The oppositely charged regions create an electric field within the air between them. This electric field varies in relation to the strength of the surface charge on the base of the thundercloud – the greater the accumulated charge, the higher the electrical field.
+
+The best studied and understood form of lightning is cloud to ground (CG). Although more common, intracloud (IC) and cloud to cloud (CC) flashes are very difficult to study given there are no "physical" points to monitor inside the clouds. Also, given the very low probability lightning will strike the same point repeatedly and consistently, scientific inquiry is difficult at best even in the areas of high CG frequency. As such, knowing flash propagation is similar amongst all forms of lightning, the best means to describe the process is through an examination of the most studied form, cloud to ground.
+
+In a process not well understood, a bidirectional channel of ionized air, called a "leader", is initiated between oppositely-charged regions in a thundercloud. Leaders are electrically conductive channels of ionized gas that propagate through, or are otherwise attracted to, regions with a charge opposite of that of the leader tip. The negative end of the bidirectional leader fills a positive charge region, also called a well, inside the cloud while the positive end fills a negative charge well. Leaders often split, forming branches in a tree-like pattern.[25] In addition, negative and some positive leaders travel in a discontinuous fashion, in a process called "stepping". The resulting jerky movement of the leaders can be readily observed in slow-motion videos of lightning flashes.
+
+It is possible for one end of the leader to fill the oppositely-charged well entirely while the other end is still active. When this happens, the leader end which filled the well may propagate outside of the thundercloud and result in either a cloud-to-air flash or a cloud-to-ground flash. In a typical cloud-to-ground flash, a bidirectional leader initiates between the main negative and lower positive charge regions in a thundercloud. The weaker positive charge region is filled quickly by the negative leader which then propagates toward the inductively-charged ground.
+
+The positively and negatively charged leaders proceed in opposite directions, positive upwards within the cloud and negative towards the earth. Both ionic channels proceed, in their respective directions, in a number of successive spurts. Each leader "pools" ions at the leading tips, shooting out one or more new leaders, momentarily pooling again to concentrate charged ions, then shooting out another leader. The negative leader continues to propagate and split as it heads downward, often speeding up as it gets closer to the Earth's surface.
+
+About 90% of ionic channel lengths between "pools" are approximately 45 m (148 ft) in length.[26] The establishment of the ionic channel takes a comparatively long amount of time (hundreds of milliseconds) in comparison to the resulting discharge, which occurs within a few dozen microseconds. The electric current needed to establish the channel, measured in the tens or hundreds of amperes, is dwarfed by subsequent currents during the actual discharge.
+
+Initiation of the lightning leaders is not well understood. The electric field strength within the thundercloud is not typically large enough to initiate this process by itself.[27] Many hypotheses have been proposed. One theory postulates that showers of relativistic electrons are created by cosmic rays and are then accelerated to higher velocities via a process called runaway breakdown. As these relativistic electrons collide and ionize neutral air molecules, they initiate leader formation. Another theory involves locally enhanced electric fields being formed near elongated water droplets or ice crystals.[28] Percolation theory, especially for the case of biased percolation,[29][clarification needed] describes random connectivity phenomena, which produce an evolution of connected structures similar to that of lightning strikes.
+
+When a stepped leader approaches the ground, the presence of opposite charges on the ground enhances the strength of the electric field. The electric field is strongest on grounded objects whose tops are closest to the base of the thundercloud, such as trees and tall buildings. If the electric field is strong enough, a positively charged ionic channel, called a positive or upward streamer, can develop from these points. This was first theorized by Heinz Kasemir.
+[30]
+[31]
+[32]
+
+As negatively charged leaders approach, increasing the localized electric field strength, grounded objects already experiencing corona discharge exceed a threshold and form upward streamers.
+
+Once a downward leader connects to an available upward leader, a process referred to as attachment, a low-resistance path is formed and discharge may occur. Photographs have been taken in which unattached streamers are clearly visible. The unattached downward leaders are also visible in branched lightning, none of which are connected to the earth, although it may appear they are. High-speed videos can show the attachment process in progress.[33]
+
+Once a conductive channel bridges the air gap between the negative charge excess in the cloud and the positive surface charge excess below, there is a large drop in resistance across the lightning channel. Electrons accelerate rapidly as a result in a zone beginning at the point of attachment, which expands across the entire leader network at a fraction of the speed of light. This is the 'return stroke' and it is the most luminous and noticeable part of the lightning discharge.
+
+A large electric current flows along the plasma channel from the cloud to the ground, neutralising the positive ground charge as electrons flow away from the strike point to the surrounding area. This huge surge of current creates large radial voltage differences along the surface of the ground. Called step potentials, they are responsible for more injuries and deaths than the strike itself.[34] Electricity takes every path available to it.[35]
+A portion of the return stroke current will often preferentially flow through one leg and out another, electrocuting an unlucky human or animal standing near the point where the lightning strikes.
+
+The electric current of the return stroke averages 30 kiloamperes for a typical negative CG flash, often referred to as "negative CG" lightning. In some cases, a ground to cloud (GC) lightning flash may originate from a positively charged region on the ground below a storm. These discharges normally originate from the tops of very tall structures, such as communications antennas. The rate at which the return stroke current travels has been found to be around 100,000 km/s.[36]
+
+The massive flow of electric current occurring during the return stroke combined with the rate at which it occurs (measured in microseconds) rapidly superheats the completed leader channel, forming a highly electrically conductive plasma channel. The core temperature of the plasma during the return stroke may exceed 50,000 K, causing it to brilliantly radiate with a blue-white color. Once the electric current stops flowing, the channel cools and dissipates over tens or hundreds of milliseconds, often disappearing as fragmented patches of glowing gas. The nearly instantaneous heating during the return stroke causes the air to expand explosively, producing a powerful shock wave which is heard as thunder.
+
+High-speed videos (examined frame-by-frame) show that most negative CG lightning flashes are made up of 3 or 4 individual strokes, though there may be as many as 30.[37]
+
+Each re-strike is separated by a relatively large amount of time, typically 40 to 50 milliseconds, as other charged regions in the cloud are discharged in subsequent strokes. Re-strikes often cause a noticeable "strobe light" effect.[38]
+
+To understand why multiple return strokes utilize the same lightning channel, one needs to understand the behavior of positive leaders, which a typical ground flash effectively becomes following the negative leader's connection with the ground. Positive leaders decay more rapidly than negative leaders do. For reasons not well understood, bidirectional leaders tend to initiate on the tips of the decayed positive leaders in which the negative end attempts to re-ionize the leader network. These leaders, also called recoil leaders, usually decay shortly after their formation. When they do manage to make contact with a conductive portion of the main leader network, a return stroke-like process occurs and a dart leader travels across all or a portion of the length of the original leader. The dart leaders making connections with the ground are what cause a majority of subsequent return strokes.[39]
+
+Each successive stroke is preceded by intermediate dart leader strokes that have a faster rise time but lower amplitude than the initial return stroke. Each subsequent stroke usually re-uses the discharge channel taken by the previous one, but the channel may be offset from its previous position as wind displaces the hot channel.[40]
+
+Since recoil and dart leader processes do not occur on negative leaders, subsequent return strokes very seldom utilize the same channel on positive ground flashes which are explained later in the article.[39]
+
+The electric current within a typical negative CG lightning discharge rises very quickly to its peak value in 1–10 microseconds, then decays more slowly over 50–200 microseconds. The transient nature of the current within a lightning flash results in several phenomena that need to be addressed in the effective protection of ground-based structures. Rapidly changing currents tend to travel on the surface of a conductor, in what is called the skin effect, unlike direct currents, which "flow-through" the entire conductor like water through a hose. Hence, conductors used in the protection of facilities tend to be multi-stranded, with small wires woven together. This increases the total bundle surface area in inverse proportion to the individual strand radius, for a fixed total cross-sectional area.
+
+The rapidly changing currents also create electromagnetic pulses (EMPs) that radiate outward from the ionic channel. This is a characteristic of all electrical discharges. The radiated pulses rapidly weaken as their distance from the origin increases. However, if they pass over conductive elements such as power lines, communication lines, or metallic pipes, they may induce a current which travels outward to its termination. The surge current is inversely related to the Surge impedance ... so the higher in impedance, then the lower the current.[41] This is the "surge" that, more often than not, results in the destruction of delicate electronics, electrical appliances, or electric motors. Devices known as surge protectors (SPD) or transient voltage surge suppressors (TVSS) attached in parallel with these lines can detect the lightning flash's transient irregular current, and, through alteration of its physical properties, route the spike to an attached earthing ground, thereby protecting the equipment from damage.
+
+There are three primary types of lightning, defined by what is at the "ends" of a flash channel.
+
+There are variations of each type, such as "positive" versus "negative" CG flashes, that have different physical characteristics common to each which can be measured. Different common names used to describe a particular lightning event may be attributed to the same or different events.
+
+Cloud-to-ground (CG) lightning is a lightning discharge between a thundercloud and the ground. It is initiated by a stepped leader moving down from the cloud, which is met by a streamer moving up from the ground.
+
+CG is the least common, but best understood of all types of lightning.  It is easier to study scientifically, because it terminates on a physical object, namely the Earth, and lends itself to being measured by instruments on the ground. Of the three primary types of lightning, it poses the greatest threat to life and property since it terminates or "strikes" the Earth. 
+The overall discharge, termed a flash, is composed of a number of processes such as preliminary breakdown, stepped leaders, connecting leaders, return strokes, dart leaders and subsequent return strokes.[42]
+
+
+
+Cloud-to-ground (CG) lightning is either positive or negative, as defined by the direction of the conventional electric current from cloud to ground.  Most CG lightning is negative, meaning that a negative charge is transferred to ground and electrons travel downward along the lightning channel. The reverse happens in a positive CG flash, where electrons travel upward along the lightning channel and a positive charge is transferred to the ground. Positive lightning is less common than negative lightning, and on average makes up less than 5% of all lightning strikes.[43]
+
+There are six different mechanisms theorized to result in the formation of downward positive lightning.[44]
+
+Contrary to popular belief, positive lightning flashes do not necessarily originate from the anvil or the upper positive charge region and strike a rain-free area outside of the thunderstorm. This belief is based on the outdated idea that lightning leaders are unipolar in nature and originating from their respective charge region.
+
+Positive lightning strikes tend to be much more intense than their negative counterparts. An average bolt of negative lightning carries an electric current of 30,000 amperes (30 kA), and transfers 15 coulombs of electric charge and 1 gigajoule of energy. Large bolts of positive lightning can carry up to 120 kA and 350 C.[45] The average positive ground flash has roughly double the peak current of a typical negative flash, and can produce peak currents up to 400 kA and charges of several hundred coulombs.[46][47] Furthermore, positive ground flashes with high peak currents are commonly followed by long continuing currents, a correlation not seen in negative ground flashes.[48]
+
+As a result of their greater power, as well as lack of warning, positive lightning strikes are considerably more dangerous. Due to the aforementioned tendency for positive ground flashes to produce both high peak currents and long continuing current, they are capable of heating surfaces to much higher levels which increases the likelihood of a fire being ignited.
+
+Positive lightning has also been shown to trigger the occurrence of upward lightning flashes from the tops of tall structures and is largely responsible for the initiation of sprites several tens of kilometers above ground level. Positive lightning tends to occur more frequently in winter storms, as with thundersnow, during intense tornadoes[49] and in the dissipation stage of a thunderstorm.[50] Huge quantities of extremely low frequency (ELF) and very low frequency (VLF) radio waves are also generated.[51]
+
+A unique form of cloud-to-ground lightning exists where lightning appears to exit from the cumulonimbus cloud and propagate a considerable distance through clear air before veering towards, and striking, the ground. For this reason, they are known as "bolts from the blue". Despite the popular misconception that these are positive lightning strikes due to them seemingly originating from the positive charge region, observations have shown that these are in fact negative flashes. They begin as intracloud flashes within the cloud, the negative leader then exits the cloud from the positive charge region before propagating through clear air and striking the ground some distance away.[52][53]
+
+Lightning discharges may occur between areas of cloud without contacting the ground. When it occurs between two separate clouds it is known as inter-cloud lightning, and when it occurs between areas of differing electric potential within a single cloud it is known as intra-cloud lightning. Intra-cloud lightning is the most frequently occurring type.[50]
+
+Intra-cloud lightning most commonly occurs between the upper anvil portion and lower reaches of a given thunderstorm. This lightning can sometimes be observed at great distances at night as so-called "sheet lightning". In such instances, the observer may see only a flash of light without hearing any thunder.
+
+Another term used for cloud–cloud or cloud–cloud–ground lightning is "Anvil Crawler", due to the habit of charge, typically originating beneath or within the anvil and scrambling through the upper cloud layers of a thunderstorm, often generating dramatic multiple branch strokes. These are usually seen as a thunderstorm passes over the observer or begins to decay. The most vivid crawler behavior occurs in well developed thunderstorms that feature extensive rear anvil shearing.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
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+Objects struck by lightning experience heat and magnetic forces of great magnitude. The heat created by lightning currents traveling through a tree may vaporize its sap, causing a steam explosion that bursts the trunk. As lightning travels through sandy soil, the soil surrounding the plasma channel may melt, forming tubular structures called fulgurites. Although 90 percent of people struck by lightning survive,[74] humans or animals struck by lightning may suffer severe injury due to internal organ and nervous system damage. Buildings or tall structures hit by lightning may be damaged as the lightning seeks unintended paths to ground. By safely conducting a lightning strike to ground, a lightning protection system can greatly reduce the probability of severe property damage. Lightning also serves an important role in the nitrogen cycle by oxidizing diatomic nitrogen in the air into nitrates which are deposited by rain and can fertilize the growth of plants and other organisms.[75][76] Due to their metallic fuselages, aircraft are highly susceptible to lightning strikes, though it does not cause much harm to the aircraft or its passengers, aside from a small hole in the wings. Due to the conductive properties of Aluminium alloy, the fuselage acts as a Faraday cage.
+
+Because the electrostatic discharge of terrestrial lightning superheats the air to plasma temperatures along the length of the discharge channel in a short duration, kinetic theory dictates gaseous molecules undergo a rapid increase in pressure and thus expand outward from the lightning creating a shock wave audible as thunder. Since the sound waves propagate not from a single point source but along the length of the lightning's path, the sound origin's varying distances from the observer can generate a rolling or rumbling effect. Perception of the sonic characteristics is further complicated by factors such as the irregular and possibly branching geometry of the lightning channel, by acoustic echoing from terrain, and by the usually multiple-stroke characteristic of the lightning strike.
+
+Light travels at about 300,000,000 m/s (980,000,000 ft/s), and sound travels through air at about 343 m/s (1,130 ft/s). An observer can approximate the distance to the strike by timing the interval between the visible lightning and the audible thunder it generates. A lightning flash preceding its thunder by one second would be approximately 343 m (1,125 ft) in distance; a delay of three seconds would indicate a distance of about 1 km or 0.62 mi (3 × 343 m). A flash preceding thunder by five seconds would indicate a distance of approximately 1.7 km or 1.1 mi (5 × 343 m). Consequently, a lightning strike observed at a very close distance will be accompanied by a sudden clap of thunder, with almost no perceptible time lapse, possibly accompanied by the smell of ozone (O3).
+
+Lightning at a sufficient distance may be seen and not heard; there is data that a lightning storm can be seen at over 160 km (100 mi) whereas the thunder travels about 32 km (20 mi). Anecdotally, there are many examples of people saying 'the storm was directly overhead or all-around and yet there was no thunder'. Since thunderclouds can be up to 20 km high[77], lightning occurring high up in the cloud may appear close but is actually too far away to produce noticeable thunder.
+
+The production of X-rays by a bolt of lightning was theoretically predicted as early as 1925,[78] but no evidence was found until 2001/2002,[79][80][81] when researchers at the New Mexico Institute of Mining and Technology detected X-ray emissions from an induced lightning strike along a grounded wire trailed behind a rocket shot into a storm cloud. In the same year University of Florida and Florida Tech researchers used an array of electric field and X-ray detectors at a lightning research facility in North Florida to confirm that natural lightning makes X-rays in large quantities during the propagation of stepped leaders. The cause of the X-ray emissions is still a matter for research, as the temperature of lightning is too low to account for the X-rays observed.[82][83]
+
+A number of observations by space-based telescopes have revealed even higher energy gamma ray emissions, the so-called terrestrial gamma-ray flashes (TGFs). These observations pose a challenge to current theories of lightning, especially with the recent discovery of the clear signatures of antimatter produced in lightning.[84] Recent research has shown that secondary species, produced by these TGFs, such as electrons, positrons, neutrons or protons, can gain energies of up to several tens of MeV.[85][86]
+
+The very high temperatures generated by lightning lead to significant local increases in ozone and oxides of nitrogen. Each lightning flash in temperate and sub-tropical areas produces 7 kg of NOx on average.[87] In the troposphere the effect of lightning can increase NOx by 90% and ozone by 30%.[88]
+
+Volcanic activity produces lightning-friendly conditions in multiple ways. The enormous quantity of pulverized material and gases explosively ejected into the atmosphere creates a dense plume of particles. The ash density and constant motion within the volcanic plume produces charge by frictional interactions (triboelectrification), resulting in very powerful and very frequent flashes as the cloud attempts to neutralize itself. Due to the extensive solid material (ash) content, unlike the water rich charge generating zones of a normal thundercloud, it is often called a dirty thunderstorm.
+
+Lightning has been observed within the atmospheres of other planets, such as Jupiter and Saturn. Although in the minority on Earth, superbolts appear to be common on Jupiter.
+
+Lightning on Venus has been a controversial subject after decades of study. During the Soviet Venera and U.S. Pioneer missions of the 1970s and 1980s, signals suggesting lightning may be present in the upper atmosphere were detected.[91] Although the Cassini–Huygens mission fly-by of Venus in 1999 detected no signs of lightning, the observation window lasted mere hours. Radio pulses recorded by the spacecraft Venus Express (which began orbiting Venus in April 2006) may originate from lightning on Venus.
+
+Thunder is heard as a rolling, gradually dissipating rumble because the sound from different portions of a long stroke arrives at slightly different times.[94]
+
+When the local electric field exceeds the dielectric strength of damp air (about 3 megavolts per meter), electrical discharge results in a strike, often followed by commensurate discharges branching from the same path. Mechanisms that cause the charges to build up to lightning are still a matter of scientific investigation.[95][96]  New study confirming dielectric breakdown is involved. Rison 2016.  Lightning may be caused by the circulation of warm moisture-filled air through electric fields.[97] Ice or water particles then accumulate charge as in a Van de Graaff generator.[98]
+
+Researchers at the University of Florida found that the final one-dimensional speeds of 10 flashes observed were between 1.0×105 and 1.4×106 m/s, with an average of 4.4×105 m/s.[99]
+
+The earliest detector invented to warn of the approach of a thunder storm was the lightning bell. Benjamin Franklin installed one such device in his house.[100][101] The detector was based on an electrostatic device called the 'electric chimes' invented by Andrew Gordon in 1742.
+
+Lightning discharges generate a wide range of electromagnetic radiations, including radio-frequency pulses. The times at which a pulse from a given lightning discharge arrives at several receivers can be used to locate the source of the discharge with a precision on the order of meters. The United States federal government has constructed a nationwide grid of such lightning detectors, allowing lightning discharges to be tracked in real time throughout the continental U.S.[102][103]
+In addition, a private global detection system that consists of over 500 detection station owned and operated by hobbyists/volunteers provides near real-time lightning maps at blitzortung.org
+
+The Earth-ionosphere waveguide traps electromagnetic VLF- and ELF waves. Electromagnetic pulses transmitted by lightning strikes propagate within that waveguide. The waveguide is dispersive, which means that their group velocity depends on frequency. The difference of the group time delay of a lightning pulse at adjacent frequencies is proportional to the distance between transmitter and receiver. Together with direction-finding methods, this allows locating lightning strikes up to distances of 10,000 km from their origin. Moreover, the eigenfrequencies of the Earth-ionospheric waveguide, the Schumann resonances
+at about 7.5 Hz, are used to determine the global thunderstorm activity.[104]
+
+In addition to ground-based lightning detection, several instruments aboard satellites have been constructed to observe lightning distribution. These include the Optical Transient Detector (OTD), aboard the OrbView-1 satellite launched on April 3, 1995, and the subsequent Lightning Imaging Sensor (LIS) aboard TRMM launched on November 28, 1997.[105][106][107]
+
+Starting in 2016, the National Oceanic and Atmospheric Administration launched Geostationary Operational Environmental Satellite–R Series (GOES-R) weather satellites outfitted with Geostationary Lightning Mapper (GLM) instruments which are near-infrared optical transient detectors that can detect the momentary changes in an optical scene, indicating the presence of lightning. [108][109]  The lighting detection data can be converted into a real-time map of lightning activity across the Western Hemisphere; this mapping technique has been implemented by the United States National Weather Service. [110]
+
+The movement of electrical charges produces a magnetic field (see electromagnetism). The intense currents of a lightning discharge create a fleeting but very strong magnetic field. Where the lightning current path passes through rock, soil, or metal these materials can become permanently magnetized. This effect is known as lightning-induced remanent magnetism, or LIRM. These currents follow the least resistive path, often horizontally near the surface[125][126] but sometimes vertically, where faults, ore bodies, or ground water offers a less resistive path.[127] One theory suggests that lodestones, natural magnets encountered in ancient times, were created in this manner.[128]
+
+Lightning-induced magnetic anomalies can be mapped in the ground,[129][130] and analysis of magnetized materials can confirm lightning was the source of the magnetization[131] and provide an estimate of the peak current of the lightning discharge.[132]
+
+Research at the University of Innsbruck has found that magnetic fields generated by plasma may induce hallucinations in subjects located within 200 m (660 ft) of a severe lightning storm.[133]
+
+Some high energy cosmic rays produced by supernovas as well as solar particles from the solar wind, enter the atmosphere and electrify the air, which may create pathways for lightning bolts.[134]
+
+In many cultures, lightning has been viewed as part of a deity or a deity in and of itself. These include the Greek god Zeus, the Aztec god Tlaloc, the Mayan God K, Slavic mythology's Perun, the Baltic Pērkons/Perkūnas, Thor in Norse mythology, Ukko in Finnish mythology, the Hindu god Indra, and the Shinto god Raijin.[135] In the traditional religion of the African Bantu tribes, lightning is a sign of the ire of the gods. Verses in the Jewish religion and in Islam also ascribe supernatural importance to lightning. In Christianity, the Second Coming of Jesus is compared to lightning.[Matthew 24:27][Luke 17:24]
+
+The expression "Lightning never strikes twice (in the same place)" is similar to "Opportunity never knocks twice" in the vein of a "once in a lifetime" opportunity, i.e., something that is generally considered improbable. Lightning occurs frequently and more so in specific areas. Since various factors alter the probability of strikes at any given location, repeat lightning strikes have a very low probability (but are not impossible).[136][137] Similarly, "A bolt from the blue" refers to something totally unexpected, and "A person being struck by lightning" is an imaginative or comedic metaphor for someone to experience a once in a lifetime, striking, sudden lightning-speed revelation, similar to an epiphany or an enlightenment.
+
+Some political parties use lightning flashes as a symbol of power, such as the People's Action Party in Singapore, the British Union of Fascists during the 1930s, and the National States' Rights Party in the United States during the 1950s.[138] The Schutzstaffel, the paramilitary wing of the Nazi Party, used the Sig rune in their logo which symbolizes lightning. The German word Blitzkrieg, which means "lightning war", was a major offensive strategy of the German army during World War II.
+
+In French and Italian, the expression for "Love at first sight" is coup de foudre and colpo di fulmine, respectively, which literally translated means "lightning strike". Some European languages have a separate word for lightning which strikes the ground (as opposed to lightning in general); often it is a cognate of the English word "rays". The name of Australia's most celebrated thoroughbred horse, Phar Lap, derives from the shared Zhuang and Thai word for lightning.[139]
+
+The bolt of lightning in heraldry is called a thunderbolt and is shown as a zigzag with non-pointed ends. This symbol usually represents power and speed.
+
+The lightning bolt is used to represent the instantaneous communication capabilities of electrically powered telegraphs and radios. It was a commonly used motif in Art Deco design, especially the zig-zag Art Deco design of the late 1920s.[140] The lightning bolt is a common insignia for military communications units throughout the world. A lightning bolt is also the NATO symbol for a signal asset.
+
+The Unicode symbol for lightning is ☇ U+2607.
+
+This article incorporates public domain material from the National Oceanic and Atmospheric Administration document: "Understanding Lightning: Thunderstorm Electrification".

en/2052.html.txt

@@ -0,0 +1,238 @@
+
+
+
+
+Martialinae
+
+Leptanillinae
+
+Amblyoponinae
+
+Paraponerinae
+
+Agroecomyrmecinae
+
+Ponerinae
+
+Proceratiinae
+
+Ecitoninae‡
+
+Aenictinae‡
+
+Dorylini‡
+
+Aenictogitoninae‡
+
+Cerapachyinae‡*
+
+Leptanilloidinae‡
+
+Dolichoderinae
+
+Aneuretinae
+
+Pseudomyrmecinae
+
+Myrmeciinae
+
+Ectatomminae
+
+Heteroponerinae
+
+Myrmicinae
+
+Formicinae
+
+A phylogeny of the extant ant subfamilies.[2][3]
+*Cerapachyinae is paraphyletic
+‡ The previous dorylomorph subfamilies were synonymized under Dorylinae by Brady et al. in 2014[4]
+
+Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants appear in the fossil record across the globe in considerable diversity during the latest Early Cretaceous and early Late Cretaceous, suggesting an earlier origin. Ants evolved from vespoid wasp ancestors in the Cretaceous period, and diversified after the rise of flowering plants. More than 12,500 of an estimated total of 22,000 species have been classified. They are easily identified by their elbowed antennae and the distinctive node-like structure that forms their slender waists.
+
+Ants form colonies that range in size from a few dozen predatory individuals living in small natural cavities to highly organised colonies that may occupy large territories and consist of millions of individuals. Larger colonies consist of various castes of sterile, wingless females, most of which are workers (ergates), as well as soldiers (dinergates) and other specialised groups. Nearly all ant colonies also have some fertile males called "drones" (aner) and one or more fertile females called "queens" (gynes). The colonies are described as superorganisms because the ants appear to operate as a unified entity, collectively working together to support the colony.
+
+Ants have colonised almost every landmass on Earth. The only places lacking indigenous ants are Antarctica and a few remote or inhospitable islands. Ants thrive in most ecosystems and may form 15–25% of the terrestrial animal biomass. Their success in so many environments has been attributed to their social organisation and their ability to modify habitats, tap resources, and defend themselves. Their long co-evolution with other species has led to mimetic, commensal, parasitic, and mutualistic relationships.
+
+Ant societies have division of labour, communication between individuals, and an ability to solve complex problems. These parallels with human societies have long been an inspiration and subject of study. Many human cultures make use of ants in cuisine, medication, and rituals. Some species are valued in their role as biological pest control agents. Their ability to exploit resources may bring ants into conflict with humans, however, as they can damage crops and invade buildings. Some species, such as the red imported fire ant (Solenopsis invicta), are regarded as invasive species, establishing themselves in areas where they have been introduced accidentally.
+
+The word ant and its chiefly dialectal form emmet[5] come from ante, emete of Middle English, which come from ǣmette of Old English, and these are all related to the dialectal Dutch emt and the Old High German āmeiza, from which comes the modern German Ameise. All of these words come from West Germanic *ǣmaitjōn, and the original meaning of the word was "the biter" (from Proto-Germanic *ai-, "off, away" + *mait- "cut").[6][7] The family name Formicidae is derived from the Latin formīca ("ant")[8] from which the words in other Romance languages, such as the Portuguese formiga, Italian formica, Spanish hormiga, Romanian furnică, and French fourmi are derived. It has been hypothesised that a Proto-Indo-European word *morwi- was used, cf. Sanskrit vamrah, Latin formīca, Greek μύρμηξ mýrmēx, Old Church Slavonic mraviji, Old Irish moirb, Old Norse maurr, Dutch mier.[9]
+
+Chrysidoidea
+
+Vespidae
+
+Rhopalosomatidae
+
+Pompilidae
+
+Tiphiidae
+
+Scolioidea
+
+Apoidea
+
+Formicidae
+
+The family Formicidae belongs to the order Hymenoptera, which also includes sawflies, bees, and wasps. Ants evolved from a lineage within the stinging wasps, and a 2013 study suggests that they are a sister group of the Apoidea.[10] In 1966, E. O. Wilson and his colleagues identified the fossil remains of an ant (Sphecomyrma) that lived in the Cretaceous period. The specimen, trapped in amber dating back to around 92 million years ago, has features found in some wasps, but not found in modern ants.[11] Sphecomyrma was possibly a ground forager, while Haidomyrmex and Haidomyrmodes, related genera in subfamily Sphecomyrminae, are reconstructed as active arboreal predators.[12] Older ants in the genus Sphecomyrmodes have been found in 99 million year-old amber from Myanmar.[13][14] A 2006 study suggested that ants arose tens of millions of years earlier than previously thought, up to 168 million years ago.[1] After the rise of flowering plants about 100 million years ago they diversified and assumed ecological dominance around 60 million years ago.[15][1][16][17] Some groups, such as the Leptanillinae and Martialinae, are suggested to have diversified from early primitive ants that were likely to have been predators underneath the surface of the soil.[3][18]
+
+During the Cretaceous period, a few species of primitive ants ranged widely on the Laurasian supercontinent (the Northern Hemisphere). They were scarce in comparison to the populations of other insects, representing only about 1% of the entire insect population. Ants became dominant after adaptive radiation at the beginning of the Paleogene period. By the Oligocene and Miocene, ants had come to represent 20–40% of all insects found in major fossil deposits. Of the species that lived in the Eocene epoch, around one in 10 genera survive to the present. Genera surviving today comprise 56% of the genera in Baltic amber fossils (early Oligocene), and 92% of the genera in Dominican amber fossils (apparently early Miocene).[15][19]
+
+Termites live in colonies and are sometimes called ‘white ants’, but termites are not ants. They are the sub-order Isoptera, and together with cockroaches they form the order Blattodea. Blattodeans are related to mantids, crickets, and other winged insects that do not undergo full metamorphosis. Like ants, termites are eusocial, with sterile workers, but they differ greatly in the genetics of reproduction. The similarity of their social structure to that of ants is attributed to convergent evolution.[20] Velvet ants look like large ants, but are wingless female wasps.[21][22]
+
+Ants are found on all continents except Antarctica, and only a few large islands, such as Greenland, Iceland, parts of Polynesia and the Hawaiian Islands lack native ant species.[24][25] Ants occupy a wide range of ecological niches and exploit many different food resources as direct or indirect herbivores, predators and scavengers. Most ant species are omnivorous generalists, but a few are specialist feeders. Their ecological dominance is demonstrated by their biomass: ants are estimated to contribute 15–20 % (on average and nearly 25% in the tropics) of terrestrial animal biomass, exceeding that of the vertebrates.[26]
+
+Ants range in size from 0.75 to 52 millimetres (0.030–2.0 in),[27][28] the largest species being the fossil Titanomyrma giganteum, the queen of which was 6 centimetres (2.4 in) long with a wingspan of 15 centimetres (5.9 in).[29] Ants vary in colour; most ants are red or black, but a few species are green and some tropical species have a metallic lustre. More than 12,000 species are currently known (with upper estimates of the potential existence of about 22,000) (see the article List of ant genera), with the greatest diversity in the tropics. Taxonomic studies continue to resolve the classification and systematics of ants. Online databases of ant species, including AntBase and the Hymenoptera Name Server, help to keep track of the known and newly described species.[30] The relative ease with which ants may be sampled and studied in ecosystems has made them useful as indicator species in biodiversity studies.[31][32]
+
+Ants are distinct in their morphology from other insects in having elbowed antennae, metapleural glands, and a strong constriction of their second abdominal segment into a node-like petiole. The head, mesosoma, and metasoma are the three distinct body segments (formally tagmata). The petiole forms a narrow waist between their mesosoma (thorax plus the first abdominal segment, which is fused to it) and gaster (abdomen less the abdominal segments in the petiole). The petiole may be formed by one or two nodes (the second alone, or the second and third abdominal segments).[33]
+
+Like other insects, ants have an exoskeleton, an external covering that provides a protective casing around the body and a point of attachment for muscles, in contrast to the internal skeletons of humans and other vertebrates. Insects do not have lungs; oxygen and other gases, such as carbon dioxide, pass through their exoskeleton via tiny valves called spiracles. Insects also lack closed blood vessels; instead, they have a long, thin, perforated tube along the top of the body (called the "dorsal aorta") that functions like a heart, and pumps haemolymph toward the head, thus driving the circulation of the internal fluids. The nervous system consists of a ventral nerve cord that runs the length of the body, with several ganglia and branches along the way reaching into the extremities of the appendages.[34]
+
+An ant's head contains many sensory organs. Like most insects, ants have compound eyes made from numerous tiny lenses attached together. Ant eyes are good for acute movement detection, but do not offer a high resolution image. They also have three small ocelli (simple eyes) on the top of the head that detect light levels and polarization.[35] Compared to vertebrates, ants tend to have blurrier eyesight, particularly in smaller species,[36] and a few subterranean taxa are completely blind.[2] However, some ants, such as Australia's bulldog ant, have excellent vision and are capable of discriminating the distance and size of objects moving nearly a metre away.[37]
+
+Two antennae ("feelers") are attached to the head; these organs detect chemicals, air currents, and vibrations; they also are used to transmit and receive signals through touch. The head has two strong jaws, the mandibles, used to carry food, manipulate objects, construct nests, and for defence.[34] In some species, a small pocket (infrabuccal chamber) inside the mouth stores food, so it may be passed to other ants or their larvae.[38]
+
+Both the legs and wings of the ant are attached to the mesosoma ("thorax"). The legs terminate in a hooked claw which allows them to hook on and climb surfaces.[39] Only reproductive ants, queens, and males, have wings. Queens shed their wings after the nuptial flight, leaving visible stubs, a distinguishing feature of queens. In a few species, wingless queens (ergatoids) and males occur.[34]
+
+The metasoma (the "abdomen") of the ant houses important internal organs, including those of the reproductive, respiratory (tracheae), and excretory systems. Workers of many species have their egg-laying structures modified into stings that are used for subduing prey and defending their nests.[34]
+
+In the colonies of a few ant species, there are physical castes—workers in distinct size-classes, called minor, median, and major ergates. Often, the larger ants have disproportionately larger heads, and correspondingly stronger mandibles. These are known as macrergates while smaller workers are known as micrergates.[40] Although formally known as dinergates, such individuals are sometimes called "soldier" ants because their stronger mandibles make them more effective in fighting, although they still are workers and their "duties" typically do not vary greatly from the minor or median workers. In a few species, the median workers are absent, creating a sharp divide between the minors and majors.[41] Weaver ants, for example, have a distinct bimodal size distribution.[42][43] Some other species show continuous variation in the size of workers. The smallest and largest workers in Pheidologeton diversus show nearly a 500-fold difference in their dry-weights.[44]
+
+Workers cannot mate; however, because of the haplodiploid sex-determination system in ants, workers of a number of species can lay unfertilised eggs that become fully fertile, haploid males. The role of workers may change with their age and in some species, such as honeypot ants, young workers are fed until their gasters are distended, and act as living food storage vessels. These food storage workers are called repletes.[45] For instance, these replete workers develop in the North American honeypot ant Myrmecocystus mexicanus. Usually the largest workers in the colony develop into repletes; and, if repletes are removed from the colony, other workers become repletes, demonstrating the flexibility of this particular polymorphism.[46] This polymorphism in morphology and behaviour of workers initially was thought to be determined by environmental factors such as nutrition and hormones that led to different developmental paths; however, genetic differences between worker castes have been noted in Acromyrmex sp.[47] These polymorphisms are caused by relatively small genetic changes; differences in a single gene of Solenopsis invicta can decide whether the colony will have single or multiple queens.[48] The Australian jack jumper ant (Myrmecia pilosula) has only a single pair of chromosomes (with the males having just one chromosome as they are haploid), the lowest number known for any animal, making it an interesting subject for studies in the genetics and developmental biology of social insects.[49][50]
+
+The life of an ant starts from an egg; if the egg is fertilised, the progeny will be female diploid, if not, it will be male haploid. Ants develop by complete metamorphosis with the larva stages passing through a pupal stage before emerging as an adult. The larva is largely immobile and is fed and cared for by workers. Food is given to the larvae by trophallaxis, a process in which an ant regurgitates liquid food held in its crop. This is also how adults share food, stored in the "social stomach". Larvae, especially in the later stages, may also be provided solid food, such as trophic eggs, pieces of prey, and seeds brought by workers.[51]
+
+The larvae grow through a series of four or five moults and enter the pupal stage. The pupa has the appendages free and not fused to the body as in a butterfly pupa.[52] The differentiation into queens and workers (which are both female), and different castes of workers, is influenced in some species by the nutrition the larvae obtain. Genetic influences and the control of gene expression by the developmental environment are complex and the determination of caste continues to be a subject of research.[53] Winged male ants, called drones, emerge from pupae along with the usually winged breeding females. Some species, such as army ants, have wingless queens. Larvae and pupae need to be kept at fairly constant temperatures to ensure proper development, and so often are moved around among the various brood chambers within the colony.[54]
+
+A new ergate spends the first few days of its adult life caring for the queen and young. She then graduates to digging and other nest work, and later to defending the nest and foraging. These changes are sometimes fairly sudden, and define what are called temporal castes. An explanation for the sequence is suggested by the high casualties involved in foraging, making it an acceptable risk only for ants who are older and are likely to die soon of natural causes.[55][56]
+
+Ant colonies can be long-lived. The queens can live for up to 30 years, and workers live from 1 to 3 years. Males, however, are more transitory, being quite short-lived and surviving for only a few weeks.[57] Ant queens are estimated to live 100 times as long as solitary insects of a similar size.[58]
+
+Ants are active all year long in the tropics, but, in cooler regions, they survive the winter in a state of dormancy known as hibernation. The forms of inactivity are varied and some temperate species have larvae going into the inactive state (diapause), while in others, the adults alone pass the winter in a state of reduced activity.[59]
+
+A wide range of reproductive strategies have been noted in ant species. Females of many species are known to be capable of reproducing asexually through thelytokous parthenogenesis.[60] Secretions from the male accessory glands in some species can plug the female genital opening and prevent females from re-mating.[61] Most ant species have a system in which only the queen and breeding females have the ability to mate. Contrary to popular belief, some ant nests have multiple queens, while others may exist without queens. Workers with the ability to reproduce are called "gamergates" and colonies that lack queens are then called gamergate colonies; colonies with queens are said to be queen-right.[62]
+
+Drones can also mate with existing queens by entering a foreign colony. When the drone is initially attacked by the workers, it releases a mating pheromone. If recognized as a mate, it will be carried to the queen to mate.[63] Males may also patrol the nest and fight others by grabbing them with their mandibles, piercing their exoskeleton and then marking them with a pheromone. The marked male is interpreted as an invader by worker ants and is killed.[64]
+
+Most ants are univoltine, producing a new generation each year.[65] During the species-specific breeding period, winged females and winged males, known to entomologists as alates, leave the colony in what is called a nuptial flight. The nuptial flight usually takes place in the late spring or early summer when the weather is hot and humid. Heat makes flying easier and freshly fallen rain makes the ground softer for mated queens to dig nests.[66] Males typically take flight before the females. Males then use visual cues to find a common mating ground, for example, a landmark such as a pine tree to which other males in the area converge. Males secrete a mating pheromone that females follow. Males will mount females in the air, but the actual mating process usually takes place on the ground. Females of some species mate with just one male but in others they may mate with as many as ten or more different males, storing the sperm in their spermathecae.[67]
+
+Mated females then seek a suitable place to begin a colony. There, they break off their wings and begin to lay and care for eggs. The females can selectively fertilise future eggs with the sperm stored to produce diploid workers or lay unfertilized haploid eggs to produce drones. The first workers to hatch are known as nanitics,[68] and are weaker and smaller than later workers, but they begin to serve the colony immediately. They enlarge the nest, forage for food, and care for the other eggs. Species that have multiple queens may have a queen leaving the nest along with some workers to found a colony at a new site,[67] a process akin to swarming in honeybees.
+
+Ants communicate with each other using pheromones, sounds, and touch.[69] The use of pheromones as chemical signals is more developed in ants, such as the red harvester ant, than in other hymenopteran groups. Like other insects, ants perceive smells with their long, thin, and mobile antennae. The paired antennae provide information about the direction and intensity of scents. Since most ants live on the ground, they use the soil surface to leave pheromone trails that may be followed by other ants. In species that forage in groups, a forager that finds food marks a trail on the way back to the colony; this trail is followed by other ants, these ants then reinforce the trail when they head back with food to the colony. When the food source is exhausted, no new trails are marked by returning ants and the scent slowly dissipates. This behaviour helps ants deal with changes in their environment. For instance, when an established path to a food source is blocked by an obstacle, the foragers leave the path to explore new routes. If an ant is successful, it leaves a new trail marking the shortest route on its return. Successful trails are followed by more ants, reinforcing better routes and gradually identifying the best path.[70]
+
+Ants use pheromones for more than just making trails. A crushed ant emits an alarm pheromone that sends nearby ants into an attack frenzy and attracts more ants from farther away. Several ant species even use "propaganda pheromones" to confuse enemy ants and make them fight among themselves.[71] Pheromones are produced by a wide range of structures including Dufour's glands, poison glands and glands on the hindgut, pygidium, rectum, sternum, and hind tibia.[58] Pheromones also are exchanged, mixed with food, and passed by trophallaxis, transferring information within the colony.[72] This allows other ants to detect what task group (e.g., foraging or nest maintenance) other colony members belong to.[73] In ant species with queen castes, when the dominant queen stops producing a specific pheromone, workers begin to raise new queens in the colony.[74]
+
+Some ants produce sounds by stridulation, using the gaster segments and their mandibles. Sounds may be used to communicate with colony members or with other species.[75][76]
+
+Ants attack and defend themselves by biting and, in many species, by stinging, often injecting or spraying chemicals, such as formic acid in the case of formicine ants, alkaloids and piperidines in fire ants, and a variety of protein components in other ants. Bullet ants (Paraponera), located in Central and South America, are considered to have the most painful sting of any insect, although it is usually not fatal to humans. This sting is given the highest rating on the Schmidt sting pain index.[77]
+
+The sting of jack jumper ants can be fatal,[78] and an antivenom has been developed for it.[79]
+
+Fire ants, Solenopsis spp., are unique in having a venom sac containing piperidine alkaloids.[80] Their stings are painful and can be dangerous to hypersensitive people.[81]
+
+Trap-jaw ants of the genus Odontomachus are equipped with mandibles called trap-jaws, which snap shut faster than any other predatory appendages within the animal kingdom.[82] One study of Odontomachus bauri recorded peak speeds of between 126 and 230 km/h (78 and 143 mph), with the jaws closing within 130 microseconds on average.
+The ants were also observed to use their jaws as a catapult to eject intruders or fling themselves backward to escape a threat.[82] Before striking, the ant opens its mandibles extremely widely and locks them in this position by an internal mechanism. Energy is stored in a thick band of muscle and explosively released when triggered by the stimulation of sensory organs resembling hairs on the inside of the mandibles. The mandibles also permit slow and fine movements for other tasks. Trap-jaws also are seen in the following genera: Anochetus, Orectognathus, and Strumigenys,[82] plus some members of the Dacetini tribe,[83] which are viewed as examples of convergent evolution.
+
+A Malaysian species of ant in the Camponotus cylindricus group has enlarged mandibular glands that extend into their gaster. If combat takes a turn for the worse, a worker may perform a final act of suicidal altruism by rupturing the membrane of its gaster, causing the content of its mandibular glands to burst from the anterior region of its head, spraying a poisonous, corrosive secretion containing acetophenones and other chemicals that immobilise small insect attackers. The worker subsequently dies.[84]
+
+Suicidal defences by workers are also noted in a Brazilian ant, Forelius pusillus, where a small group of ants leaves the security of the nest after sealing the entrance from the outside each evening.[85]
+
+In addition to defence against predators, ants need to protect their colonies from pathogens. Some worker ants maintain the hygiene of the colony and their activities include undertaking or necrophory, the disposal of dead nest-mates.[86] Oleic acid has been identified as the compound released from dead ants that triggers necrophoric behaviour in Atta mexicana[87] while workers of Linepithema humile react to the absence of characteristic chemicals (dolichodial and iridomyrmecin) present on the cuticle of their living nestmates to trigger similar behaviour.[88]
+
+Nests may be protected from physical threats such as flooding and overheating by elaborate nest architecture.[89][90] Workers of Cataulacus muticus, an arboreal species that lives in plant hollows, respond to flooding by drinking water inside the nest, and excreting it outside.[91] Camponotus anderseni, which nests in the cavities of wood in mangrove habitats, deals with submergence under water by switching to anaerobic respiration.[92]
+
+Many animals can learn behaviours by imitation, but ants may be the only group apart from mammals where interactive teaching has been observed. A knowledgeable forager of Temnothorax albipennis can lead a naïve nest-mate to newly discovered food by the process of tandem running. The follower obtains knowledge through its leading tutor. The leader is acutely sensitive to the progress of the follower and slows down when the follower lags and speeds up when the follower gets too close.[93]
+
+Controlled experiments with colonies of Cerapachys biroi suggest that an individual may choose nest roles based on her previous experience. An entire generation of identical workers was divided into two groups whose outcome in food foraging was controlled. One group was continually rewarded with prey, while it was made certain that the other failed. As a result, members of the successful group intensified their foraging attempts while the unsuccessful group ventured out fewer and fewer times. A month later, the successful foragers continued in their role while the others had moved to specialise in brood care.[94]
+
+Complex nests are built by many ant species, but other species are nomadic and do not build permanent structures. Ants may form subterranean nests or build them on trees. These nests may be found in the ground, under stones or logs, inside logs, hollow stems, or even acorns. The materials used for construction include soil and plant matter,[67] and ants carefully select their nest sites; Temnothorax albipennis will avoid sites with dead ants, as these may indicate the presence of pests or disease. They are quick to abandon established nests at the first sign of threats.[95]
+
+The army ants of South America, such as the Eciton burchellii species, and the driver ants of Africa do not build permanent nests, but instead, alternate between nomadism and stages where the workers form a temporary nest (bivouac) from their own bodies, by holding each other together.[96]
+
+Weaver ant (Oecophylla spp.) workers build nests in trees by attaching leaves together, first pulling them together with bridges of workers and then inducing their larvae to produce silk as they are moved along the leaf edges. Similar forms of nest construction are seen in some species of Polyrhachis.[97]
+
+Formica polyctena, among other ant species, constructs nests that maintain a relatively constant interior temperature that aids in the development of larvae. The ants maintain the nest temperature by choosing the location, nest materials, controlling ventilation and maintaining the heat from solar radiation, worker activity and metabolism, and in some moist nests, microbial activity in the nest materials.[98]
+
+Some ant species, such as those that use natural cavities, can be opportunistic and make use of the controlled micro-climate provided inside human dwellings and other artificial structures to house their colonies and nest structures.[99][100]
+
+Most ants are generalist predators, scavengers, and indirect herbivores,[16] but a few have evolved specialised ways of obtaining nutrition. It is believed that many ant species that engage in indirect herbivory rely on specialized symbiosis with their gut microbes [101] to upgrade the nutritional value of the food they collect [102] and allow them to survive in nitrogen poor regions, such as rainforest canopies.[103] Leafcutter ants (Atta and Acromyrmex) feed exclusively on a fungus that grows only within their colonies. They continually collect leaves which are taken to the colony, cut into tiny pieces and placed in fungal gardens. Ergates specialise in related tasks according to their sizes. The largest ants cut stalks, smaller workers chew the leaves and the smallest tend the fungus. Leafcutter ants are sensitive enough to recognise the reaction of the fungus to different plant material, apparently detecting chemical signals from the fungus. If a particular type of leaf is found to be toxic to the fungus, the colony will no longer collect it. The ants feed on structures produced by the fungi called gongylidia. Symbiotic bacteria on the exterior surface of the ants produce antibiotics that kill bacteria introduced into the nest that may harm the fungi.[104]
+
+Foraging ants travel distances of up to 200 metres (700 ft) from their nest [105] and scent trails allow them to find their way back even in the dark. In hot and arid regions, day-foraging ants face death by desiccation, so the ability to find the shortest route back to the nest reduces that risk. Diurnal desert ants of the genus Cataglyphis such as the Sahara desert ant navigate by keeping track of direction as well as distance travelled. Distances travelled are measured using an internal pedometer that keeps count of the steps taken[106] and also by evaluating the movement of objects in their visual field (optical flow).[107] Directions are measured using the position of the sun.[108]
+They integrate this information to find the shortest route back to their nest.[109]
+Like all ants, they can also make use of visual landmarks when available[110] as well as olfactory and tactile cues to navigate.[111][112] Some species of ant are able to use the Earth's magnetic field for navigation.[113] The compound eyes of ants have specialised cells that detect polarised light from the Sun, which is used to determine direction.[114][115]
+These polarization detectors are sensitive in the ultraviolet region of the light spectrum.[116] In some army ant species, a group of foragers who become separated from the main column may sometimes turn back on themselves and form a circular ant mill. The workers may then run around continuously until they die of exhaustion.[117]
+
+The female worker ants do not have wings and reproductive females lose their wings after their mating flights in order to begin their colonies. Therefore, unlike their wasp ancestors, most ants travel by walking. Some species are capable of leaping. For example, Jerdon's jumping ant (Harpegnathos saltator) is able to jump by synchronising the action of its mid and hind pairs of legs.[118] There are several species of gliding ant including Cephalotes atratus; this may be a common trait among arboreal ants with small colonies. Ants with this ability are able to control their horizontal movement so as to catch tree trunks when they fall from atop the forest canopy.[119]
+
+Other species of ants can form chains to bridge gaps over water, underground, or through spaces in vegetation. Some species also form floating rafts that help them survive floods.[120]  These rafts may also have a role in allowing ants to colonise islands.[121] Polyrhachis sokolova, a species of ant found in Australian mangrove swamps, can swim and live in underwater nests. Since they lack gills, they go to trapped pockets of air in the submerged nests to breathe.[122]
+
+Not all ants have the same kind of societies. The Australian bulldog ants are among the biggest and most basal of ants. Like virtually all ants, they are eusocial, but their social behaviour is poorly developed compared to other species. Each individual hunts alone, using her large eyes instead of chemical senses to find prey.[123]
+
+Some species (such as Tetramorium caespitum) attack and take over neighbouring ant colonies. Others are less expansionist, but just as aggressive; they invade colonies to steal eggs or larvae, which they either eat or raise as workers or slaves. Extreme specialists among these slave-raiding ants, such as the Amazon ants, are incapable of feeding themselves and need captured workers to survive.[124] Captured workers of enslaved Temnothorax species have evolved a counter strategy, destroying just the female pupae of the slave-making Temnothorax americanus, but sparing the males (who don't take part in slave-raiding as adults).[125]
+
+Ants identify kin and nestmates through their scent, which comes from hydrocarbon-laced secretions that coat their exoskeletons. If an ant is separated from its original colony, it will eventually lose the colony scent. Any ant that enters a colony without a matching scent will be attacked.[126] Also, the reason why two separate colonies of ants will attack each other even if they are of the same species is because the genes responsible for pheromone production are different between them. The Argentine ant, however, does not have this characteristic, due to lack of genetic diversity, and has become a global pest because of it.
+
+Parasitic ant species enter the colonies of host ants and establish themselves as social parasites; species such as Strumigenys xenos are entirely parasitic and do not have workers, but instead, rely on the food gathered by their Strumigenys perplexa hosts.[127][128] This form of parasitism is seen across many ant genera, but the parasitic ant is usually a species that is closely related to its host. A variety of methods are employed to enter the nest of the host ant. A parasitic queen may enter the host nest before the first brood has hatched, establishing herself prior to development of a colony scent. Other species use pheromones to confuse the host ants or to trick them into carrying the parasitic queen into the nest. Some simply fight their way into the nest.[129]
+
+A conflict between the sexes of a species is seen in some species of ants with these reproducers apparently competing to produce offspring that are as closely related to them as possible. The most extreme form involves the production of clonal offspring. An extreme of sexual conflict is seen in Wasmannia auropunctata, where the queens produce diploid daughters by thelytokous parthenogenesis and males produce clones by a process whereby a diploid egg loses its maternal contribution to produce haploid males who are clones of the father.[130]
+
+Ants form symbiotic associations with a range of species, including other ant species, other insects, plants, and fungi. They also are preyed on by many animals and even certain fungi. Some arthropod species spend part of their lives within ant nests, either preying on ants, their larvae, and eggs, consuming the food stores of the ants, or avoiding predators. These inquilines may bear a close resemblance to ants. The nature of this ant mimicry (myrmecomorphy) varies, with some cases involving Batesian mimicry, where the mimic reduces the risk of predation. Others show Wasmannian mimicry, a form of mimicry seen only in inquilines.[131][132]
+
+Aphids and other hemipteran insects secrete a sweet liquid called honeydew, when they feed on plant sap. The sugars in honeydew are a high-energy food source, which many ant species collect.[133] In some cases, the aphids secrete the honeydew in response to ants tapping them with their antennae. The ants in turn keep predators away from the aphids and will move them from one feeding location to another. When migrating to a new area, many colonies will take the aphids with them, to ensure a continued supply of honeydew. Ants also tend mealybugs to harvest their honeydew. Mealybugs may become a serious pest of pineapples if ants are present to protect mealybugs from their natural enemies.[134]
+
+Myrmecophilous (ant-loving) caterpillars of the butterfly family Lycaenidae (e.g., blues, coppers, or hairstreaks) are herded by the ants, led to feeding areas in the daytime, and brought inside the ants' nest at night. The caterpillars have a gland which secretes honeydew when the ants massage them. Some caterpillars produce vibrations and sounds that are perceived by the ants.[135] A similar adaptation can be seen in Grizzled skipper butterflies that emit vibrations by expanding their wings in order to communicate with ants, which are natural predators of these butterflies.[136] Other caterpillars have evolved from ant-loving to ant-eating: these myrmecophagous caterpillars secrete a pheromone that makes the ants act as if the caterpillar is one of their own larvae. The caterpillar is then taken into the ant nest where it feeds on the ant larvae.[137] A number of specialized bacterial have been found as endosymbionts in ant guts. Some of the dominant bacteria belong to the order Rhizobiales whose members are known for being nitrogen-fixing symbionts in legumes but the species found in ant lack the ability to fix nitrogen.[138][139] Fungus-growing ants that make up the tribe Attini, including leafcutter ants, cultivate certain species of fungus in the genera Leucoagaricus or Leucocoprinus of the family Agaricaceae. In this ant-fungus mutualism, both species depend on each other for survival. The ant Allomerus decemarticulatus has evolved a three-way association with the host plant, Hirtella physophora (Chrysobalanaceae), and a sticky fungus which is used to trap their insect prey.[140]
+
+Lemon ants make devil's gardens by killing surrounding plants with their stings and leaving a pure patch of lemon ant trees, (Duroia hirsuta). This modification of the forest provides the ants with more nesting sites inside the stems of the Duroia trees.[141] Although some ants obtain nectar from flowers, pollination by ants is somewhat rare, one example being of the pollination of the orchid Leporella fimbriata which induces male Myrmecia urens to pseudocopulate with the flowers, transferring pollen in the process.[142] One theory that has been proposed for the rarity of pollination is that the secretions of the metapleural gland inactivate and reduce the viability of pollen.[143][144] Some plants have special nectar exuding structures, extrafloral nectaries, that provide food for ants, which in turn protect the plant from more damaging herbivorous insects.[145] Species such as the bullhorn acacia (Acacia cornigera) in Central America have hollow thorns that house colonies of stinging ants (Pseudomyrmex ferruginea) who defend the tree against insects, browsing mammals, and epiphytic vines. Isotopic labelling studies suggest that plants also obtain nitrogen from the ants.[146] In return, the ants obtain food from protein- and lipid-rich Beltian bodies. In Fiji Philidris nagasau (Dolichoderinae) are known to selectively grow species of epiphytic Squamellaria (Rubiaceae) which produce large domatia inside which the ant colonies nest. The ants plant the seeds and the domatia of young seedling are immediately occupied and the ant faeces in them contribute to rapid growth.[147] Similar dispersal associations are found with other dolichoderines in the region as well.[148] Another example of this type of ectosymbiosis comes from the Macaranga tree, which has stems adapted to house colonies of Crematogaster ants.[149]
+
+Many plant species have seeds that are adapted for dispersal by ants.[150] Seed dispersal by ants or myrmecochory is widespread, and new estimates suggest that nearly 9% of all plant species may have such ant associations.[151][150] Often, seed-dispersing ants perform directed dispersal, depositing the seeds in locations that increase the likelihood of seed survival to reproduction.[152] Some plants in arid, fire-prone systems are particularly dependent on ants for their survival and dispersal as the seeds are transported to safety below the ground.[153] Many ant-dispersed seeds have special external structures, elaiosomes, that are sought after by ants as food.[154]
+
+A convergence, possibly a form of mimicry, is seen in the eggs of stick insects. They have an edible elaiosome-like structure and are taken into the ant nest where the young hatch.[155]
+
+Most ants are predatory and some prey on and obtain food from other social insects including other ants. Some species specialise in preying on termites (Megaponera and Termitopone) while a few Cerapachyinae prey on other ants.[105] Some termites, including Nasutitermes corniger, form associations with certain ant species to keep away predatory ant species.[156] The tropical wasp Mischocyttarus drewseni coats the pedicel of its nest with an ant-repellent chemical.[157] It is suggested that many tropical wasps may build their nests in trees and cover them to protect themselves from ants. Other wasps, such as A. multipicta, defend against ants by blasting them off the nest with bursts of wing buzzing.[158] Stingless bees (Trigona and Melipona) use chemical defences against ants.[105]
+
+Flies in the Old World genus Bengalia (Calliphoridae) prey on ants and are kleptoparasites, snatching prey or brood from the mandibles of adult ants.[159] Wingless and legless females of the Malaysian phorid fly (Vestigipoda myrmolarvoidea) live in the nests of ants of the genus Aenictus and are cared for by the ants.[159]
+
+Fungi in the genera Cordyceps and Ophiocordyceps infect ants. Ants react to their infection by climbing up plants and sinking their mandibles into plant tissue. The fungus kills the ants, grows on their remains, and produces a fruiting body. It appears that the fungus alters the behaviour of the ant to help disperse its spores [160] in a microhabitat that best suits the fungus.[161] Strepsipteran parasites also manipulate their ant host to climb grass stems, to help the parasite find mates.[162]
+
+A nematode (Myrmeconema neotropicum) that infects canopy ants (Cephalotes atratus) causes the black-coloured gasters of workers to turn red. The parasite also alters the behaviour of the ant, causing them to carry their gasters high. The conspicuous red gasters are mistaken by birds for ripe fruits, such as Hyeronima alchorneoides, and eaten. The droppings of the bird are collected by other ants and fed to their young, leading to further spread of the nematode.[163]
+
+South American poison dart frogs in the genus Dendrobates feed mainly on ants, and the toxins in their skin may come from the ants.[164]
+
+Army ants forage in a wide roving column, attacking any animals in that path that are unable to escape. In Central and South America, Eciton burchellii is the swarming ant most commonly attended by "ant-following" birds such as antbirds and woodcreepers.[165][166] This behaviour was once considered mutualistic, but later studies found the birds to be parasitic. Direct kleptoparasitism (birds stealing food from the ants' grasp) is rare and has been noted in Inca doves which pick seeds at nest entrances as they are being transported by species of Pogonomyrmex.[167] Birds that follow ants eat many prey insects and thus decrease the foraging success of ants.[168] Birds indulge in a peculiar behaviour called anting that, as yet, is not fully understood. Here birds rest on ant nests, or pick and drop ants onto their wings and feathers; this may be a means to remove ectoparasites from the birds.
+
+Anteaters, aardvarks, pangolins, echidnas and numbats have special adaptations for living on a diet of ants. These adaptations include long, sticky tongues to capture ants and strong claws to break into ant nests. Brown bears (Ursus arctos) have been found to feed on ants. About 12%, 16%, and 4% of their faecal volume in spring, summer, and autumn, respectively, is composed of ants.[169]
+
+Ants perform many ecological roles that are beneficial to humans, including the suppression of pest populations and aeration of the soil. The use of weaver ants in citrus cultivation in southern China is considered one of the oldest known applications of biological control.[170] On the other hand, ants may become nuisances when they invade buildings, or cause economic losses.
+
+In some parts of the world (mainly Africa and South America), large ants, especially army ants, are used as surgical sutures. The wound is pressed together and ants are applied along it. The ant seizes the edges of the wound in its mandibles and locks in place. The body is then cut off and the head and mandibles remain in place to close the wound.[171][172][173] The large heads of the dinergates (soldiers) of the leafcutting ant Atta cephalotes are also used by native surgeons in closing wounds.[174]
+
+Some ants have toxic venom and are of medical importance. The species include Paraponera clavata (tocandira) and Dinoponera spp. (false tocandiras) of South America [175] and the Myrmecia ants of Australia.[176]
+
+In South Africa, ants are used to help harvest the seeds of rooibos (Aspalathus linearis), a plant used to make a herbal tea. The plant disperses its seeds widely, making manual collection difficult. Black ants collect and store these and other seeds in their nest, where humans can gather them en masse. Up to half a pound (200 g) of seeds may be collected from one ant-heap.[177][178]
+
+Although most ants survive attempts by humans to eradicate them, a few are highly endangered. These tend to be island species that have evolved specialized traits and risk being displaced by introduced ant species. Examples include the critically endangered Sri Lankan relict ant (Aneuretus simoni) and Adetomyrma venatrix of Madagascar.[179]
+
+It has been estimated by E.O. Wilson that the total number of individual ants alive in the world at any one time is between one and ten quadrillion (short scale) (i.e., between 1015 and 1016). According to this estimate, the total biomass of all the ants in the world is approximately equal to the total biomass of the entire human race.[180] Also, according to this estimate, there are approximately 1 million ants for every human on Earth.[181]
+
+Ants and their larvae are eaten in different parts of the world. The eggs of two species of ants are used in Mexican escamoles. They are considered a form of insect caviar and can sell for as much as US$40 per pound ($90/kg) because they are seasonal and hard to find. In the Colombian department of Santander, hormigas culonas (roughly interpreted as "large-bottomed ants") Atta laevigata are toasted alive and eaten.[182]
+
+In areas of India, and throughout Burma and Thailand, a paste of the green weaver ant (Oecophylla smaragdina) is served as a condiment with curry.[183] Weaver ant eggs and larvae, as well as the ants, may be used in a Thai salad, yam (Thai: ยำ), in a dish called yam khai mot daeng (Thai: ยำไข่มดแดง) or red ant egg salad, a dish that comes from the Issan or north-eastern region of Thailand. Saville-Kent, in the Naturalist in Australia wrote "Beauty, in the case of the green ant, is more than skin-deep. Their attractive, almost sweetmeat-like translucency possibly invited the first essays at their consumption by the human species". Mashed up in water, after the manner of lemon squash, "these ants form a pleasant acid drink which is held in high favor by the natives of North Queensland, and is even appreciated by many European palates".[184]
+
+In his First Summer in the Sierra, John Muir notes that the Digger Indians of California ate the tickling, acid gasters of the large jet-black carpenter ants. The Mexican Indians eat the replete workers, or living honey-pots, of the honey ant (Myrmecocystus).[184]
+
+Some ant species are considered as pests, primarily those that occur in human habitations, where their presence is often problematic. For example, the presence of ants would be undesirable in sterile places such as hospitals or kitchens. Some species or genera commonly categorized as pests include the Argentine ant, pavement ant, yellow crazy ant, banded sugar ant, pharaoh ant, red ant, carpenter ant, odorous house ant, red imported fire ant, and European fire ant. Some ants will raid stored food, some will seek water sources, others may damage indoor structures, some may damage agricultural crops directly (or by aiding sucking pests). Some will sting or bite.[185] The adaptive nature of ant colonies make it nearly impossible to eliminate entire colonies and most pest management practices aim to control local populations and tend to be temporary solutions. Ant populations are managed by a combination of approaches that make use of chemical, biological, and physical methods. Chemical methods include the use of insecticidal bait which is gathered by ants as food and brought back to the nest where the poison is inadvertently spread to other colony members through trophallaxis. Management is based on the species and techniques may vary according to the location and circumstance.[185]
+
+Observed by humans since the dawn of history, the behaviour of ants has been documented and the subject of early writings and fables passed from one century to another. Those using scientific methods, myrmecologists, study ants in the laboratory and in their natural conditions. Their complex and variable social structures have made ants ideal model organisms. Ultraviolet vision was first discovered in ants by Sir John Lubbock in 1881.[186] Studies on ants have tested hypotheses in ecology and sociobiology, and have been particularly important in examining the predictions of theories of kin selection and evolutionarily stable strategies.[187] Ant colonies may be studied by rearing or temporarily maintaining them in formicaria, specially constructed glass framed enclosures.[188] Individuals may be tracked for study by marking them with dots of colours.[189]
+
+The successful techniques used by ant colonies have been studied in computer science and robotics to produce distributed and fault-tolerant systems for solving problems, for example Ant colony optimization and Ant robotics. This area of biomimetics has led to studies of ant locomotion, search engines that make use of "foraging trails", fault-tolerant storage, and networking algorithms.[190]
+
+From the late 1950s through the late 1970s, ant farms were popular educational children's toys in the United States. Some later commercial versions use transparent gel instead of soil, allowing greater visibility at the cost of stressing the ants with unnatural light.[191]
+
+Anthropomorphised ants have often been used in fables and children's stories to represent industriousness and cooperative effort. They also are mentioned in religious texts.[192][193] In the Book of Proverbs in the Bible, ants are held up as a good example for humans for their hard work and cooperation.[194] Aesop did the same in his fable The Ant and the Grasshopper. In the Quran, Sulayman is said to have heard and understood an ant warning other ants to return home to avoid being accidentally crushed by Sulayman and his marching army.[Quran 27:18][195] In parts of Africa, ants are considered to be the messengers of the deities. Some Native American mythology, such as the Hopi mythology, considers ants as the very first animals. Ant bites are often said to have curative properties. The sting of some species of Pseudomyrmex is claimed to give fever relief.[196] Ant bites are used in the initiation ceremonies of some Amazon Indian cultures as a test of endurance.[197][198]
+
+Ant society has always fascinated humans and has been written about both humorously and seriously. Mark Twain wrote about ants in his 1880 book A Tramp Abroad.[199] Some modern authors have used the example of the ants to comment on the relationship between society and the individual. Examples are Robert Frost in his poem "Departmental" and T. H. White in his fantasy novel The Once and Future King. The plot in French entomologist and writer Bernard Werber's Les Fourmis science-fiction trilogy is divided between the worlds of ants and humans; ants and their behaviour is described using contemporary scientific knowledge. H.G. Wells wrote about intelligent ants destroying human settlements in Brazil and threatening human civilization in his 1905 science-fiction short story, The Empire of the Ants. In more recent times, animated cartoons and 3-D animated films featuring ants have been produced including Antz, A Bug's Life, The Ant Bully, The Ant and the Aardvark, Ferdy the Ant and Atom Ant. Renowned myrmecologist E. O. Wilson wrote a short story, "Trailhead" in 2010 for The New Yorker magazine, which describes the life and death of an ant-queen and the rise and fall of her colony, from an ants' point of view.[200] The French neuroanatomist, psychiatrist and eugenicist Auguste Forel believed that ant societies were models for human society. He published a five volume work from 1921 to 1923 that examined ant biology and society.[201]
+
+In the early 1990s, the video game SimAnt, which simulated an ant colony, won the 1992 Codie award for "Best Simulation Program".[202]
+
+Ants also are quite popular inspiration for many science-fiction insectoids, such as the Formics of Ender's Game, the Bugs of Starship Troopers, the giant ants in the films Them! and Empire of the Ants, Marvel Comics' super hero Ant-Man, and ants mutated into super-intelligence in Phase IV. In computer strategy games, ant-based species often benefit from increased production rates due to their single-minded focus, such as the Klackons in the Master of Orion series of games or the ChCht in Deadlock II. These characters are often credited with a hive mind, a common misconception about ant colonies.[203]
+

en/2053.html.txt

@@ -0,0 +1,238 @@
+
+
+
+
+Martialinae
+
+Leptanillinae
+
+Amblyoponinae
+
+Paraponerinae
+
+Agroecomyrmecinae
+
+Ponerinae
+
+Proceratiinae
+
+Ecitoninae‡
+
+Aenictinae‡
+
+Dorylini‡
+
+Aenictogitoninae‡
+
+Cerapachyinae‡*
+
+Leptanilloidinae‡
+
+Dolichoderinae
+
+Aneuretinae
+
+Pseudomyrmecinae
+
+Myrmeciinae
+
+Ectatomminae
+
+Heteroponerinae
+
+Myrmicinae
+
+Formicinae
+
+A phylogeny of the extant ant subfamilies.[2][3]
+*Cerapachyinae is paraphyletic
+‡ The previous dorylomorph subfamilies were synonymized under Dorylinae by Brady et al. in 2014[4]
+
+Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants appear in the fossil record across the globe in considerable diversity during the latest Early Cretaceous and early Late Cretaceous, suggesting an earlier origin. Ants evolved from vespoid wasp ancestors in the Cretaceous period, and diversified after the rise of flowering plants. More than 12,500 of an estimated total of 22,000 species have been classified. They are easily identified by their elbowed antennae and the distinctive node-like structure that forms their slender waists.
+
+Ants form colonies that range in size from a few dozen predatory individuals living in small natural cavities to highly organised colonies that may occupy large territories and consist of millions of individuals. Larger colonies consist of various castes of sterile, wingless females, most of which are workers (ergates), as well as soldiers (dinergates) and other specialised groups. Nearly all ant colonies also have some fertile males called "drones" (aner) and one or more fertile females called "queens" (gynes). The colonies are described as superorganisms because the ants appear to operate as a unified entity, collectively working together to support the colony.
+
+Ants have colonised almost every landmass on Earth. The only places lacking indigenous ants are Antarctica and a few remote or inhospitable islands. Ants thrive in most ecosystems and may form 15–25% of the terrestrial animal biomass. Their success in so many environments has been attributed to their social organisation and their ability to modify habitats, tap resources, and defend themselves. Their long co-evolution with other species has led to mimetic, commensal, parasitic, and mutualistic relationships.
+
+Ant societies have division of labour, communication between individuals, and an ability to solve complex problems. These parallels with human societies have long been an inspiration and subject of study. Many human cultures make use of ants in cuisine, medication, and rituals. Some species are valued in their role as biological pest control agents. Their ability to exploit resources may bring ants into conflict with humans, however, as they can damage crops and invade buildings. Some species, such as the red imported fire ant (Solenopsis invicta), are regarded as invasive species, establishing themselves in areas where they have been introduced accidentally.
+
+The word ant and its chiefly dialectal form emmet[5] come from ante, emete of Middle English, which come from ǣmette of Old English, and these are all related to the dialectal Dutch emt and the Old High German āmeiza, from which comes the modern German Ameise. All of these words come from West Germanic *ǣmaitjōn, and the original meaning of the word was "the biter" (from Proto-Germanic *ai-, "off, away" + *mait- "cut").[6][7] The family name Formicidae is derived from the Latin formīca ("ant")[8] from which the words in other Romance languages, such as the Portuguese formiga, Italian formica, Spanish hormiga, Romanian furnică, and French fourmi are derived. It has been hypothesised that a Proto-Indo-European word *morwi- was used, cf. Sanskrit vamrah, Latin formīca, Greek μύρμηξ mýrmēx, Old Church Slavonic mraviji, Old Irish moirb, Old Norse maurr, Dutch mier.[9]
+
+Chrysidoidea
+
+Vespidae
+
+Rhopalosomatidae
+
+Pompilidae
+
+Tiphiidae
+
+Scolioidea
+
+Apoidea
+
+Formicidae
+
+The family Formicidae belongs to the order Hymenoptera, which also includes sawflies, bees, and wasps. Ants evolved from a lineage within the stinging wasps, and a 2013 study suggests that they are a sister group of the Apoidea.[10] In 1966, E. O. Wilson and his colleagues identified the fossil remains of an ant (Sphecomyrma) that lived in the Cretaceous period. The specimen, trapped in amber dating back to around 92 million years ago, has features found in some wasps, but not found in modern ants.[11] Sphecomyrma was possibly a ground forager, while Haidomyrmex and Haidomyrmodes, related genera in subfamily Sphecomyrminae, are reconstructed as active arboreal predators.[12] Older ants in the genus Sphecomyrmodes have been found in 99 million year-old amber from Myanmar.[13][14] A 2006 study suggested that ants arose tens of millions of years earlier than previously thought, up to 168 million years ago.[1] After the rise of flowering plants about 100 million years ago they diversified and assumed ecological dominance around 60 million years ago.[15][1][16][17] Some groups, such as the Leptanillinae and Martialinae, are suggested to have diversified from early primitive ants that were likely to have been predators underneath the surface of the soil.[3][18]
+
+During the Cretaceous period, a few species of primitive ants ranged widely on the Laurasian supercontinent (the Northern Hemisphere). They were scarce in comparison to the populations of other insects, representing only about 1% of the entire insect population. Ants became dominant after adaptive radiation at the beginning of the Paleogene period. By the Oligocene and Miocene, ants had come to represent 20–40% of all insects found in major fossil deposits. Of the species that lived in the Eocene epoch, around one in 10 genera survive to the present. Genera surviving today comprise 56% of the genera in Baltic amber fossils (early Oligocene), and 92% of the genera in Dominican amber fossils (apparently early Miocene).[15][19]
+
+Termites live in colonies and are sometimes called ‘white ants’, but termites are not ants. They are the sub-order Isoptera, and together with cockroaches they form the order Blattodea. Blattodeans are related to mantids, crickets, and other winged insects that do not undergo full metamorphosis. Like ants, termites are eusocial, with sterile workers, but they differ greatly in the genetics of reproduction. The similarity of their social structure to that of ants is attributed to convergent evolution.[20] Velvet ants look like large ants, but are wingless female wasps.[21][22]
+
+Ants are found on all continents except Antarctica, and only a few large islands, such as Greenland, Iceland, parts of Polynesia and the Hawaiian Islands lack native ant species.[24][25] Ants occupy a wide range of ecological niches and exploit many different food resources as direct or indirect herbivores, predators and scavengers. Most ant species are omnivorous generalists, but a few are specialist feeders. Their ecological dominance is demonstrated by their biomass: ants are estimated to contribute 15–20 % (on average and nearly 25% in the tropics) of terrestrial animal biomass, exceeding that of the vertebrates.[26]
+
+Ants range in size from 0.75 to 52 millimetres (0.030–2.0 in),[27][28] the largest species being the fossil Titanomyrma giganteum, the queen of which was 6 centimetres (2.4 in) long with a wingspan of 15 centimetres (5.9 in).[29] Ants vary in colour; most ants are red or black, but a few species are green and some tropical species have a metallic lustre. More than 12,000 species are currently known (with upper estimates of the potential existence of about 22,000) (see the article List of ant genera), with the greatest diversity in the tropics. Taxonomic studies continue to resolve the classification and systematics of ants. Online databases of ant species, including AntBase and the Hymenoptera Name Server, help to keep track of the known and newly described species.[30] The relative ease with which ants may be sampled and studied in ecosystems has made them useful as indicator species in biodiversity studies.[31][32]
+
+Ants are distinct in their morphology from other insects in having elbowed antennae, metapleural glands, and a strong constriction of their second abdominal segment into a node-like petiole. The head, mesosoma, and metasoma are the three distinct body segments (formally tagmata). The petiole forms a narrow waist between their mesosoma (thorax plus the first abdominal segment, which is fused to it) and gaster (abdomen less the abdominal segments in the petiole). The petiole may be formed by one or two nodes (the second alone, or the second and third abdominal segments).[33]
+
+Like other insects, ants have an exoskeleton, an external covering that provides a protective casing around the body and a point of attachment for muscles, in contrast to the internal skeletons of humans and other vertebrates. Insects do not have lungs; oxygen and other gases, such as carbon dioxide, pass through their exoskeleton via tiny valves called spiracles. Insects also lack closed blood vessels; instead, they have a long, thin, perforated tube along the top of the body (called the "dorsal aorta") that functions like a heart, and pumps haemolymph toward the head, thus driving the circulation of the internal fluids. The nervous system consists of a ventral nerve cord that runs the length of the body, with several ganglia and branches along the way reaching into the extremities of the appendages.[34]
+
+An ant's head contains many sensory organs. Like most insects, ants have compound eyes made from numerous tiny lenses attached together. Ant eyes are good for acute movement detection, but do not offer a high resolution image. They also have three small ocelli (simple eyes) on the top of the head that detect light levels and polarization.[35] Compared to vertebrates, ants tend to have blurrier eyesight, particularly in smaller species,[36] and a few subterranean taxa are completely blind.[2] However, some ants, such as Australia's bulldog ant, have excellent vision and are capable of discriminating the distance and size of objects moving nearly a metre away.[37]
+
+Two antennae ("feelers") are attached to the head; these organs detect chemicals, air currents, and vibrations; they also are used to transmit and receive signals through touch. The head has two strong jaws, the mandibles, used to carry food, manipulate objects, construct nests, and for defence.[34] In some species, a small pocket (infrabuccal chamber) inside the mouth stores food, so it may be passed to other ants or their larvae.[38]
+
+Both the legs and wings of the ant are attached to the mesosoma ("thorax"). The legs terminate in a hooked claw which allows them to hook on and climb surfaces.[39] Only reproductive ants, queens, and males, have wings. Queens shed their wings after the nuptial flight, leaving visible stubs, a distinguishing feature of queens. In a few species, wingless queens (ergatoids) and males occur.[34]
+
+The metasoma (the "abdomen") of the ant houses important internal organs, including those of the reproductive, respiratory (tracheae), and excretory systems. Workers of many species have their egg-laying structures modified into stings that are used for subduing prey and defending their nests.[34]
+
+In the colonies of a few ant species, there are physical castes—workers in distinct size-classes, called minor, median, and major ergates. Often, the larger ants have disproportionately larger heads, and correspondingly stronger mandibles. These are known as macrergates while smaller workers are known as micrergates.[40] Although formally known as dinergates, such individuals are sometimes called "soldier" ants because their stronger mandibles make them more effective in fighting, although they still are workers and their "duties" typically do not vary greatly from the minor or median workers. In a few species, the median workers are absent, creating a sharp divide between the minors and majors.[41] Weaver ants, for example, have a distinct bimodal size distribution.[42][43] Some other species show continuous variation in the size of workers. The smallest and largest workers in Pheidologeton diversus show nearly a 500-fold difference in their dry-weights.[44]
+
+Workers cannot mate; however, because of the haplodiploid sex-determination system in ants, workers of a number of species can lay unfertilised eggs that become fully fertile, haploid males. The role of workers may change with their age and in some species, such as honeypot ants, young workers are fed until their gasters are distended, and act as living food storage vessels. These food storage workers are called repletes.[45] For instance, these replete workers develop in the North American honeypot ant Myrmecocystus mexicanus. Usually the largest workers in the colony develop into repletes; and, if repletes are removed from the colony, other workers become repletes, demonstrating the flexibility of this particular polymorphism.[46] This polymorphism in morphology and behaviour of workers initially was thought to be determined by environmental factors such as nutrition and hormones that led to different developmental paths; however, genetic differences between worker castes have been noted in Acromyrmex sp.[47] These polymorphisms are caused by relatively small genetic changes; differences in a single gene of Solenopsis invicta can decide whether the colony will have single or multiple queens.[48] The Australian jack jumper ant (Myrmecia pilosula) has only a single pair of chromosomes (with the males having just one chromosome as they are haploid), the lowest number known for any animal, making it an interesting subject for studies in the genetics and developmental biology of social insects.[49][50]
+
+The life of an ant starts from an egg; if the egg is fertilised, the progeny will be female diploid, if not, it will be male haploid. Ants develop by complete metamorphosis with the larva stages passing through a pupal stage before emerging as an adult. The larva is largely immobile and is fed and cared for by workers. Food is given to the larvae by trophallaxis, a process in which an ant regurgitates liquid food held in its crop. This is also how adults share food, stored in the "social stomach". Larvae, especially in the later stages, may also be provided solid food, such as trophic eggs, pieces of prey, and seeds brought by workers.[51]
+
+The larvae grow through a series of four or five moults and enter the pupal stage. The pupa has the appendages free and not fused to the body as in a butterfly pupa.[52] The differentiation into queens and workers (which are both female), and different castes of workers, is influenced in some species by the nutrition the larvae obtain. Genetic influences and the control of gene expression by the developmental environment are complex and the determination of caste continues to be a subject of research.[53] Winged male ants, called drones, emerge from pupae along with the usually winged breeding females. Some species, such as army ants, have wingless queens. Larvae and pupae need to be kept at fairly constant temperatures to ensure proper development, and so often are moved around among the various brood chambers within the colony.[54]
+
+A new ergate spends the first few days of its adult life caring for the queen and young. She then graduates to digging and other nest work, and later to defending the nest and foraging. These changes are sometimes fairly sudden, and define what are called temporal castes. An explanation for the sequence is suggested by the high casualties involved in foraging, making it an acceptable risk only for ants who are older and are likely to die soon of natural causes.[55][56]
+
+Ant colonies can be long-lived. The queens can live for up to 30 years, and workers live from 1 to 3 years. Males, however, are more transitory, being quite short-lived and surviving for only a few weeks.[57] Ant queens are estimated to live 100 times as long as solitary insects of a similar size.[58]
+
+Ants are active all year long in the tropics, but, in cooler regions, they survive the winter in a state of dormancy known as hibernation. The forms of inactivity are varied and some temperate species have larvae going into the inactive state (diapause), while in others, the adults alone pass the winter in a state of reduced activity.[59]
+
+A wide range of reproductive strategies have been noted in ant species. Females of many species are known to be capable of reproducing asexually through thelytokous parthenogenesis.[60] Secretions from the male accessory glands in some species can plug the female genital opening and prevent females from re-mating.[61] Most ant species have a system in which only the queen and breeding females have the ability to mate. Contrary to popular belief, some ant nests have multiple queens, while others may exist without queens. Workers with the ability to reproduce are called "gamergates" and colonies that lack queens are then called gamergate colonies; colonies with queens are said to be queen-right.[62]
+
+Drones can also mate with existing queens by entering a foreign colony. When the drone is initially attacked by the workers, it releases a mating pheromone. If recognized as a mate, it will be carried to the queen to mate.[63] Males may also patrol the nest and fight others by grabbing them with their mandibles, piercing their exoskeleton and then marking them with a pheromone. The marked male is interpreted as an invader by worker ants and is killed.[64]
+
+Most ants are univoltine, producing a new generation each year.[65] During the species-specific breeding period, winged females and winged males, known to entomologists as alates, leave the colony in what is called a nuptial flight. The nuptial flight usually takes place in the late spring or early summer when the weather is hot and humid. Heat makes flying easier and freshly fallen rain makes the ground softer for mated queens to dig nests.[66] Males typically take flight before the females. Males then use visual cues to find a common mating ground, for example, a landmark such as a pine tree to which other males in the area converge. Males secrete a mating pheromone that females follow. Males will mount females in the air, but the actual mating process usually takes place on the ground. Females of some species mate with just one male but in others they may mate with as many as ten or more different males, storing the sperm in their spermathecae.[67]
+
+Mated females then seek a suitable place to begin a colony. There, they break off their wings and begin to lay and care for eggs. The females can selectively fertilise future eggs with the sperm stored to produce diploid workers or lay unfertilized haploid eggs to produce drones. The first workers to hatch are known as nanitics,[68] and are weaker and smaller than later workers, but they begin to serve the colony immediately. They enlarge the nest, forage for food, and care for the other eggs. Species that have multiple queens may have a queen leaving the nest along with some workers to found a colony at a new site,[67] a process akin to swarming in honeybees.
+
+Ants communicate with each other using pheromones, sounds, and touch.[69] The use of pheromones as chemical signals is more developed in ants, such as the red harvester ant, than in other hymenopteran groups. Like other insects, ants perceive smells with their long, thin, and mobile antennae. The paired antennae provide information about the direction and intensity of scents. Since most ants live on the ground, they use the soil surface to leave pheromone trails that may be followed by other ants. In species that forage in groups, a forager that finds food marks a trail on the way back to the colony; this trail is followed by other ants, these ants then reinforce the trail when they head back with food to the colony. When the food source is exhausted, no new trails are marked by returning ants and the scent slowly dissipates. This behaviour helps ants deal with changes in their environment. For instance, when an established path to a food source is blocked by an obstacle, the foragers leave the path to explore new routes. If an ant is successful, it leaves a new trail marking the shortest route on its return. Successful trails are followed by more ants, reinforcing better routes and gradually identifying the best path.[70]
+
+Ants use pheromones for more than just making trails. A crushed ant emits an alarm pheromone that sends nearby ants into an attack frenzy and attracts more ants from farther away. Several ant species even use "propaganda pheromones" to confuse enemy ants and make them fight among themselves.[71] Pheromones are produced by a wide range of structures including Dufour's glands, poison glands and glands on the hindgut, pygidium, rectum, sternum, and hind tibia.[58] Pheromones also are exchanged, mixed with food, and passed by trophallaxis, transferring information within the colony.[72] This allows other ants to detect what task group (e.g., foraging or nest maintenance) other colony members belong to.[73] In ant species with queen castes, when the dominant queen stops producing a specific pheromone, workers begin to raise new queens in the colony.[74]
+
+Some ants produce sounds by stridulation, using the gaster segments and their mandibles. Sounds may be used to communicate with colony members or with other species.[75][76]
+
+Ants attack and defend themselves by biting and, in many species, by stinging, often injecting or spraying chemicals, such as formic acid in the case of formicine ants, alkaloids and piperidines in fire ants, and a variety of protein components in other ants. Bullet ants (Paraponera), located in Central and South America, are considered to have the most painful sting of any insect, although it is usually not fatal to humans. This sting is given the highest rating on the Schmidt sting pain index.[77]
+
+The sting of jack jumper ants can be fatal,[78] and an antivenom has been developed for it.[79]
+
+Fire ants, Solenopsis spp., are unique in having a venom sac containing piperidine alkaloids.[80] Their stings are painful and can be dangerous to hypersensitive people.[81]
+
+Trap-jaw ants of the genus Odontomachus are equipped with mandibles called trap-jaws, which snap shut faster than any other predatory appendages within the animal kingdom.[82] One study of Odontomachus bauri recorded peak speeds of between 126 and 230 km/h (78 and 143 mph), with the jaws closing within 130 microseconds on average.
+The ants were also observed to use their jaws as a catapult to eject intruders or fling themselves backward to escape a threat.[82] Before striking, the ant opens its mandibles extremely widely and locks them in this position by an internal mechanism. Energy is stored in a thick band of muscle and explosively released when triggered by the stimulation of sensory organs resembling hairs on the inside of the mandibles. The mandibles also permit slow and fine movements for other tasks. Trap-jaws also are seen in the following genera: Anochetus, Orectognathus, and Strumigenys,[82] plus some members of the Dacetini tribe,[83] which are viewed as examples of convergent evolution.
+
+A Malaysian species of ant in the Camponotus cylindricus group has enlarged mandibular glands that extend into their gaster. If combat takes a turn for the worse, a worker may perform a final act of suicidal altruism by rupturing the membrane of its gaster, causing the content of its mandibular glands to burst from the anterior region of its head, spraying a poisonous, corrosive secretion containing acetophenones and other chemicals that immobilise small insect attackers. The worker subsequently dies.[84]
+
+Suicidal defences by workers are also noted in a Brazilian ant, Forelius pusillus, where a small group of ants leaves the security of the nest after sealing the entrance from the outside each evening.[85]
+
+In addition to defence against predators, ants need to protect their colonies from pathogens. Some worker ants maintain the hygiene of the colony and their activities include undertaking or necrophory, the disposal of dead nest-mates.[86] Oleic acid has been identified as the compound released from dead ants that triggers necrophoric behaviour in Atta mexicana[87] while workers of Linepithema humile react to the absence of characteristic chemicals (dolichodial and iridomyrmecin) present on the cuticle of their living nestmates to trigger similar behaviour.[88]
+
+Nests may be protected from physical threats such as flooding and overheating by elaborate nest architecture.[89][90] Workers of Cataulacus muticus, an arboreal species that lives in plant hollows, respond to flooding by drinking water inside the nest, and excreting it outside.[91] Camponotus anderseni, which nests in the cavities of wood in mangrove habitats, deals with submergence under water by switching to anaerobic respiration.[92]
+
+Many animals can learn behaviours by imitation, but ants may be the only group apart from mammals where interactive teaching has been observed. A knowledgeable forager of Temnothorax albipennis can lead a naïve nest-mate to newly discovered food by the process of tandem running. The follower obtains knowledge through its leading tutor. The leader is acutely sensitive to the progress of the follower and slows down when the follower lags and speeds up when the follower gets too close.[93]
+
+Controlled experiments with colonies of Cerapachys biroi suggest that an individual may choose nest roles based on her previous experience. An entire generation of identical workers was divided into two groups whose outcome in food foraging was controlled. One group was continually rewarded with prey, while it was made certain that the other failed. As a result, members of the successful group intensified their foraging attempts while the unsuccessful group ventured out fewer and fewer times. A month later, the successful foragers continued in their role while the others had moved to specialise in brood care.[94]
+
+Complex nests are built by many ant species, but other species are nomadic and do not build permanent structures. Ants may form subterranean nests or build them on trees. These nests may be found in the ground, under stones or logs, inside logs, hollow stems, or even acorns. The materials used for construction include soil and plant matter,[67] and ants carefully select their nest sites; Temnothorax albipennis will avoid sites with dead ants, as these may indicate the presence of pests or disease. They are quick to abandon established nests at the first sign of threats.[95]
+
+The army ants of South America, such as the Eciton burchellii species, and the driver ants of Africa do not build permanent nests, but instead, alternate between nomadism and stages where the workers form a temporary nest (bivouac) from their own bodies, by holding each other together.[96]
+
+Weaver ant (Oecophylla spp.) workers build nests in trees by attaching leaves together, first pulling them together with bridges of workers and then inducing their larvae to produce silk as they are moved along the leaf edges. Similar forms of nest construction are seen in some species of Polyrhachis.[97]
+
+Formica polyctena, among other ant species, constructs nests that maintain a relatively constant interior temperature that aids in the development of larvae. The ants maintain the nest temperature by choosing the location, nest materials, controlling ventilation and maintaining the heat from solar radiation, worker activity and metabolism, and in some moist nests, microbial activity in the nest materials.[98]
+
+Some ant species, such as those that use natural cavities, can be opportunistic and make use of the controlled micro-climate provided inside human dwellings and other artificial structures to house their colonies and nest structures.[99][100]
+
+Most ants are generalist predators, scavengers, and indirect herbivores,[16] but a few have evolved specialised ways of obtaining nutrition. It is believed that many ant species that engage in indirect herbivory rely on specialized symbiosis with their gut microbes [101] to upgrade the nutritional value of the food they collect [102] and allow them to survive in nitrogen poor regions, such as rainforest canopies.[103] Leafcutter ants (Atta and Acromyrmex) feed exclusively on a fungus that grows only within their colonies. They continually collect leaves which are taken to the colony, cut into tiny pieces and placed in fungal gardens. Ergates specialise in related tasks according to their sizes. The largest ants cut stalks, smaller workers chew the leaves and the smallest tend the fungus. Leafcutter ants are sensitive enough to recognise the reaction of the fungus to different plant material, apparently detecting chemical signals from the fungus. If a particular type of leaf is found to be toxic to the fungus, the colony will no longer collect it. The ants feed on structures produced by the fungi called gongylidia. Symbiotic bacteria on the exterior surface of the ants produce antibiotics that kill bacteria introduced into the nest that may harm the fungi.[104]
+
+Foraging ants travel distances of up to 200 metres (700 ft) from their nest [105] and scent trails allow them to find their way back even in the dark. In hot and arid regions, day-foraging ants face death by desiccation, so the ability to find the shortest route back to the nest reduces that risk. Diurnal desert ants of the genus Cataglyphis such as the Sahara desert ant navigate by keeping track of direction as well as distance travelled. Distances travelled are measured using an internal pedometer that keeps count of the steps taken[106] and also by evaluating the movement of objects in their visual field (optical flow).[107] Directions are measured using the position of the sun.[108]
+They integrate this information to find the shortest route back to their nest.[109]
+Like all ants, they can also make use of visual landmarks when available[110] as well as olfactory and tactile cues to navigate.[111][112] Some species of ant are able to use the Earth's magnetic field for navigation.[113] The compound eyes of ants have specialised cells that detect polarised light from the Sun, which is used to determine direction.[114][115]
+These polarization detectors are sensitive in the ultraviolet region of the light spectrum.[116] In some army ant species, a group of foragers who become separated from the main column may sometimes turn back on themselves and form a circular ant mill. The workers may then run around continuously until they die of exhaustion.[117]
+
+The female worker ants do not have wings and reproductive females lose their wings after their mating flights in order to begin their colonies. Therefore, unlike their wasp ancestors, most ants travel by walking. Some species are capable of leaping. For example, Jerdon's jumping ant (Harpegnathos saltator) is able to jump by synchronising the action of its mid and hind pairs of legs.[118] There are several species of gliding ant including Cephalotes atratus; this may be a common trait among arboreal ants with small colonies. Ants with this ability are able to control their horizontal movement so as to catch tree trunks when they fall from atop the forest canopy.[119]
+
+Other species of ants can form chains to bridge gaps over water, underground, or through spaces in vegetation. Some species also form floating rafts that help them survive floods.[120]  These rafts may also have a role in allowing ants to colonise islands.[121] Polyrhachis sokolova, a species of ant found in Australian mangrove swamps, can swim and live in underwater nests. Since they lack gills, they go to trapped pockets of air in the submerged nests to breathe.[122]
+
+Not all ants have the same kind of societies. The Australian bulldog ants are among the biggest and most basal of ants. Like virtually all ants, they are eusocial, but their social behaviour is poorly developed compared to other species. Each individual hunts alone, using her large eyes instead of chemical senses to find prey.[123]
+
+Some species (such as Tetramorium caespitum) attack and take over neighbouring ant colonies. Others are less expansionist, but just as aggressive; they invade colonies to steal eggs or larvae, which they either eat or raise as workers or slaves. Extreme specialists among these slave-raiding ants, such as the Amazon ants, are incapable of feeding themselves and need captured workers to survive.[124] Captured workers of enslaved Temnothorax species have evolved a counter strategy, destroying just the female pupae of the slave-making Temnothorax americanus, but sparing the males (who don't take part in slave-raiding as adults).[125]
+
+Ants identify kin and nestmates through their scent, which comes from hydrocarbon-laced secretions that coat their exoskeletons. If an ant is separated from its original colony, it will eventually lose the colony scent. Any ant that enters a colony without a matching scent will be attacked.[126] Also, the reason why two separate colonies of ants will attack each other even if they are of the same species is because the genes responsible for pheromone production are different between them. The Argentine ant, however, does not have this characteristic, due to lack of genetic diversity, and has become a global pest because of it.
+
+Parasitic ant species enter the colonies of host ants and establish themselves as social parasites; species such as Strumigenys xenos are entirely parasitic and do not have workers, but instead, rely on the food gathered by their Strumigenys perplexa hosts.[127][128] This form of parasitism is seen across many ant genera, but the parasitic ant is usually a species that is closely related to its host. A variety of methods are employed to enter the nest of the host ant. A parasitic queen may enter the host nest before the first brood has hatched, establishing herself prior to development of a colony scent. Other species use pheromones to confuse the host ants or to trick them into carrying the parasitic queen into the nest. Some simply fight their way into the nest.[129]
+
+A conflict between the sexes of a species is seen in some species of ants with these reproducers apparently competing to produce offspring that are as closely related to them as possible. The most extreme form involves the production of clonal offspring. An extreme of sexual conflict is seen in Wasmannia auropunctata, where the queens produce diploid daughters by thelytokous parthenogenesis and males produce clones by a process whereby a diploid egg loses its maternal contribution to produce haploid males who are clones of the father.[130]
+
+Ants form symbiotic associations with a range of species, including other ant species, other insects, plants, and fungi. They also are preyed on by many animals and even certain fungi. Some arthropod species spend part of their lives within ant nests, either preying on ants, their larvae, and eggs, consuming the food stores of the ants, or avoiding predators. These inquilines may bear a close resemblance to ants. The nature of this ant mimicry (myrmecomorphy) varies, with some cases involving Batesian mimicry, where the mimic reduces the risk of predation. Others show Wasmannian mimicry, a form of mimicry seen only in inquilines.[131][132]
+
+Aphids and other hemipteran insects secrete a sweet liquid called honeydew, when they feed on plant sap. The sugars in honeydew are a high-energy food source, which many ant species collect.[133] In some cases, the aphids secrete the honeydew in response to ants tapping them with their antennae. The ants in turn keep predators away from the aphids and will move them from one feeding location to another. When migrating to a new area, many colonies will take the aphids with them, to ensure a continued supply of honeydew. Ants also tend mealybugs to harvest their honeydew. Mealybugs may become a serious pest of pineapples if ants are present to protect mealybugs from their natural enemies.[134]
+
+Myrmecophilous (ant-loving) caterpillars of the butterfly family Lycaenidae (e.g., blues, coppers, or hairstreaks) are herded by the ants, led to feeding areas in the daytime, and brought inside the ants' nest at night. The caterpillars have a gland which secretes honeydew when the ants massage them. Some caterpillars produce vibrations and sounds that are perceived by the ants.[135] A similar adaptation can be seen in Grizzled skipper butterflies that emit vibrations by expanding their wings in order to communicate with ants, which are natural predators of these butterflies.[136] Other caterpillars have evolved from ant-loving to ant-eating: these myrmecophagous caterpillars secrete a pheromone that makes the ants act as if the caterpillar is one of their own larvae. The caterpillar is then taken into the ant nest where it feeds on the ant larvae.[137] A number of specialized bacterial have been found as endosymbionts in ant guts. Some of the dominant bacteria belong to the order Rhizobiales whose members are known for being nitrogen-fixing symbionts in legumes but the species found in ant lack the ability to fix nitrogen.[138][139] Fungus-growing ants that make up the tribe Attini, including leafcutter ants, cultivate certain species of fungus in the genera Leucoagaricus or Leucocoprinus of the family Agaricaceae. In this ant-fungus mutualism, both species depend on each other for survival. The ant Allomerus decemarticulatus has evolved a three-way association with the host plant, Hirtella physophora (Chrysobalanaceae), and a sticky fungus which is used to trap their insect prey.[140]
+
+Lemon ants make devil's gardens by killing surrounding plants with their stings and leaving a pure patch of lemon ant trees, (Duroia hirsuta). This modification of the forest provides the ants with more nesting sites inside the stems of the Duroia trees.[141] Although some ants obtain nectar from flowers, pollination by ants is somewhat rare, one example being of the pollination of the orchid Leporella fimbriata which induces male Myrmecia urens to pseudocopulate with the flowers, transferring pollen in the process.[142] One theory that has been proposed for the rarity of pollination is that the secretions of the metapleural gland inactivate and reduce the viability of pollen.[143][144] Some plants have special nectar exuding structures, extrafloral nectaries, that provide food for ants, which in turn protect the plant from more damaging herbivorous insects.[145] Species such as the bullhorn acacia (Acacia cornigera) in Central America have hollow thorns that house colonies of stinging ants (Pseudomyrmex ferruginea) who defend the tree against insects, browsing mammals, and epiphytic vines. Isotopic labelling studies suggest that plants also obtain nitrogen from the ants.[146] In return, the ants obtain food from protein- and lipid-rich Beltian bodies. In Fiji Philidris nagasau (Dolichoderinae) are known to selectively grow species of epiphytic Squamellaria (Rubiaceae) which produce large domatia inside which the ant colonies nest. The ants plant the seeds and the domatia of young seedling are immediately occupied and the ant faeces in them contribute to rapid growth.[147] Similar dispersal associations are found with other dolichoderines in the region as well.[148] Another example of this type of ectosymbiosis comes from the Macaranga tree, which has stems adapted to house colonies of Crematogaster ants.[149]
+
+Many plant species have seeds that are adapted for dispersal by ants.[150] Seed dispersal by ants or myrmecochory is widespread, and new estimates suggest that nearly 9% of all plant species may have such ant associations.[151][150] Often, seed-dispersing ants perform directed dispersal, depositing the seeds in locations that increase the likelihood of seed survival to reproduction.[152] Some plants in arid, fire-prone systems are particularly dependent on ants for their survival and dispersal as the seeds are transported to safety below the ground.[153] Many ant-dispersed seeds have special external structures, elaiosomes, that are sought after by ants as food.[154]
+
+A convergence, possibly a form of mimicry, is seen in the eggs of stick insects. They have an edible elaiosome-like structure and are taken into the ant nest where the young hatch.[155]
+
+Most ants are predatory and some prey on and obtain food from other social insects including other ants. Some species specialise in preying on termites (Megaponera and Termitopone) while a few Cerapachyinae prey on other ants.[105] Some termites, including Nasutitermes corniger, form associations with certain ant species to keep away predatory ant species.[156] The tropical wasp Mischocyttarus drewseni coats the pedicel of its nest with an ant-repellent chemical.[157] It is suggested that many tropical wasps may build their nests in trees and cover them to protect themselves from ants. Other wasps, such as A. multipicta, defend against ants by blasting them off the nest with bursts of wing buzzing.[158] Stingless bees (Trigona and Melipona) use chemical defences against ants.[105]
+
+Flies in the Old World genus Bengalia (Calliphoridae) prey on ants and are kleptoparasites, snatching prey or brood from the mandibles of adult ants.[159] Wingless and legless females of the Malaysian phorid fly (Vestigipoda myrmolarvoidea) live in the nests of ants of the genus Aenictus and are cared for by the ants.[159]
+
+Fungi in the genera Cordyceps and Ophiocordyceps infect ants. Ants react to their infection by climbing up plants and sinking their mandibles into plant tissue. The fungus kills the ants, grows on their remains, and produces a fruiting body. It appears that the fungus alters the behaviour of the ant to help disperse its spores [160] in a microhabitat that best suits the fungus.[161] Strepsipteran parasites also manipulate their ant host to climb grass stems, to help the parasite find mates.[162]
+
+A nematode (Myrmeconema neotropicum) that infects canopy ants (Cephalotes atratus) causes the black-coloured gasters of workers to turn red. The parasite also alters the behaviour of the ant, causing them to carry their gasters high. The conspicuous red gasters are mistaken by birds for ripe fruits, such as Hyeronima alchorneoides, and eaten. The droppings of the bird are collected by other ants and fed to their young, leading to further spread of the nematode.[163]
+
+South American poison dart frogs in the genus Dendrobates feed mainly on ants, and the toxins in their skin may come from the ants.[164]
+
+Army ants forage in a wide roving column, attacking any animals in that path that are unable to escape. In Central and South America, Eciton burchellii is the swarming ant most commonly attended by "ant-following" birds such as antbirds and woodcreepers.[165][166] This behaviour was once considered mutualistic, but later studies found the birds to be parasitic. Direct kleptoparasitism (birds stealing food from the ants' grasp) is rare and has been noted in Inca doves which pick seeds at nest entrances as they are being transported by species of Pogonomyrmex.[167] Birds that follow ants eat many prey insects and thus decrease the foraging success of ants.[168] Birds indulge in a peculiar behaviour called anting that, as yet, is not fully understood. Here birds rest on ant nests, or pick and drop ants onto their wings and feathers; this may be a means to remove ectoparasites from the birds.
+
+Anteaters, aardvarks, pangolins, echidnas and numbats have special adaptations for living on a diet of ants. These adaptations include long, sticky tongues to capture ants and strong claws to break into ant nests. Brown bears (Ursus arctos) have been found to feed on ants. About 12%, 16%, and 4% of their faecal volume in spring, summer, and autumn, respectively, is composed of ants.[169]
+
+Ants perform many ecological roles that are beneficial to humans, including the suppression of pest populations and aeration of the soil. The use of weaver ants in citrus cultivation in southern China is considered one of the oldest known applications of biological control.[170] On the other hand, ants may become nuisances when they invade buildings, or cause economic losses.
+
+In some parts of the world (mainly Africa and South America), large ants, especially army ants, are used as surgical sutures. The wound is pressed together and ants are applied along it. The ant seizes the edges of the wound in its mandibles and locks in place. The body is then cut off and the head and mandibles remain in place to close the wound.[171][172][173] The large heads of the dinergates (soldiers) of the leafcutting ant Atta cephalotes are also used by native surgeons in closing wounds.[174]
+
+Some ants have toxic venom and are of medical importance. The species include Paraponera clavata (tocandira) and Dinoponera spp. (false tocandiras) of South America [175] and the Myrmecia ants of Australia.[176]
+
+In South Africa, ants are used to help harvest the seeds of rooibos (Aspalathus linearis), a plant used to make a herbal tea. The plant disperses its seeds widely, making manual collection difficult. Black ants collect and store these and other seeds in their nest, where humans can gather them en masse. Up to half a pound (200 g) of seeds may be collected from one ant-heap.[177][178]
+
+Although most ants survive attempts by humans to eradicate them, a few are highly endangered. These tend to be island species that have evolved specialized traits and risk being displaced by introduced ant species. Examples include the critically endangered Sri Lankan relict ant (Aneuretus simoni) and Adetomyrma venatrix of Madagascar.[179]
+
+It has been estimated by E.O. Wilson that the total number of individual ants alive in the world at any one time is between one and ten quadrillion (short scale) (i.e., between 1015 and 1016). According to this estimate, the total biomass of all the ants in the world is approximately equal to the total biomass of the entire human race.[180] Also, according to this estimate, there are approximately 1 million ants for every human on Earth.[181]
+
+Ants and their larvae are eaten in different parts of the world. The eggs of two species of ants are used in Mexican escamoles. They are considered a form of insect caviar and can sell for as much as US$40 per pound ($90/kg) because they are seasonal and hard to find. In the Colombian department of Santander, hormigas culonas (roughly interpreted as "large-bottomed ants") Atta laevigata are toasted alive and eaten.[182]
+
+In areas of India, and throughout Burma and Thailand, a paste of the green weaver ant (Oecophylla smaragdina) is served as a condiment with curry.[183] Weaver ant eggs and larvae, as well as the ants, may be used in a Thai salad, yam (Thai: ยำ), in a dish called yam khai mot daeng (Thai: ยำไข่มดแดง) or red ant egg salad, a dish that comes from the Issan or north-eastern region of Thailand. Saville-Kent, in the Naturalist in Australia wrote "Beauty, in the case of the green ant, is more than skin-deep. Their attractive, almost sweetmeat-like translucency possibly invited the first essays at their consumption by the human species". Mashed up in water, after the manner of lemon squash, "these ants form a pleasant acid drink which is held in high favor by the natives of North Queensland, and is even appreciated by many European palates".[184]
+
+In his First Summer in the Sierra, John Muir notes that the Digger Indians of California ate the tickling, acid gasters of the large jet-black carpenter ants. The Mexican Indians eat the replete workers, or living honey-pots, of the honey ant (Myrmecocystus).[184]
+
+Some ant species are considered as pests, primarily those that occur in human habitations, where their presence is often problematic. For example, the presence of ants would be undesirable in sterile places such as hospitals or kitchens. Some species or genera commonly categorized as pests include the Argentine ant, pavement ant, yellow crazy ant, banded sugar ant, pharaoh ant, red ant, carpenter ant, odorous house ant, red imported fire ant, and European fire ant. Some ants will raid stored food, some will seek water sources, others may damage indoor structures, some may damage agricultural crops directly (or by aiding sucking pests). Some will sting or bite.[185] The adaptive nature of ant colonies make it nearly impossible to eliminate entire colonies and most pest management practices aim to control local populations and tend to be temporary solutions. Ant populations are managed by a combination of approaches that make use of chemical, biological, and physical methods. Chemical methods include the use of insecticidal bait which is gathered by ants as food and brought back to the nest where the poison is inadvertently spread to other colony members through trophallaxis. Management is based on the species and techniques may vary according to the location and circumstance.[185]
+
+Observed by humans since the dawn of history, the behaviour of ants has been documented and the subject of early writings and fables passed from one century to another. Those using scientific methods, myrmecologists, study ants in the laboratory and in their natural conditions. Their complex and variable social structures have made ants ideal model organisms. Ultraviolet vision was first discovered in ants by Sir John Lubbock in 1881.[186] Studies on ants have tested hypotheses in ecology and sociobiology, and have been particularly important in examining the predictions of theories of kin selection and evolutionarily stable strategies.[187] Ant colonies may be studied by rearing or temporarily maintaining them in formicaria, specially constructed glass framed enclosures.[188] Individuals may be tracked for study by marking them with dots of colours.[189]
+
+The successful techniques used by ant colonies have been studied in computer science and robotics to produce distributed and fault-tolerant systems for solving problems, for example Ant colony optimization and Ant robotics. This area of biomimetics has led to studies of ant locomotion, search engines that make use of "foraging trails", fault-tolerant storage, and networking algorithms.[190]
+
+From the late 1950s through the late 1970s, ant farms were popular educational children's toys in the United States. Some later commercial versions use transparent gel instead of soil, allowing greater visibility at the cost of stressing the ants with unnatural light.[191]
+
+Anthropomorphised ants have often been used in fables and children's stories to represent industriousness and cooperative effort. They also are mentioned in religious texts.[192][193] In the Book of Proverbs in the Bible, ants are held up as a good example for humans for their hard work and cooperation.[194] Aesop did the same in his fable The Ant and the Grasshopper. In the Quran, Sulayman is said to have heard and understood an ant warning other ants to return home to avoid being accidentally crushed by Sulayman and his marching army.[Quran 27:18][195] In parts of Africa, ants are considered to be the messengers of the deities. Some Native American mythology, such as the Hopi mythology, considers ants as the very first animals. Ant bites are often said to have curative properties. The sting of some species of Pseudomyrmex is claimed to give fever relief.[196] Ant bites are used in the initiation ceremonies of some Amazon Indian cultures as a test of endurance.[197][198]
+
+Ant society has always fascinated humans and has been written about both humorously and seriously. Mark Twain wrote about ants in his 1880 book A Tramp Abroad.[199] Some modern authors have used the example of the ants to comment on the relationship between society and the individual. Examples are Robert Frost in his poem "Departmental" and T. H. White in his fantasy novel The Once and Future King. The plot in French entomologist and writer Bernard Werber's Les Fourmis science-fiction trilogy is divided between the worlds of ants and humans; ants and their behaviour is described using contemporary scientific knowledge. H.G. Wells wrote about intelligent ants destroying human settlements in Brazil and threatening human civilization in his 1905 science-fiction short story, The Empire of the Ants. In more recent times, animated cartoons and 3-D animated films featuring ants have been produced including Antz, A Bug's Life, The Ant Bully, The Ant and the Aardvark, Ferdy the Ant and Atom Ant. Renowned myrmecologist E. O. Wilson wrote a short story, "Trailhead" in 2010 for The New Yorker magazine, which describes the life and death of an ant-queen and the rise and fall of her colony, from an ants' point of view.[200] The French neuroanatomist, psychiatrist and eugenicist Auguste Forel believed that ant societies were models for human society. He published a five volume work from 1921 to 1923 that examined ant biology and society.[201]
+
+In the early 1990s, the video game SimAnt, which simulated an ant colony, won the 1992 Codie award for "Best Simulation Program".[202]
+
+Ants also are quite popular inspiration for many science-fiction insectoids, such as the Formics of Ender's Game, the Bugs of Starship Troopers, the giant ants in the films Them! and Empire of the Ants, Marvel Comics' super hero Ant-Man, and ants mutated into super-intelligence in Phase IV. In computer strategy games, ant-based species often benefit from increased production rates due to their single-minded focus, such as the Klackons in the Master of Orion series of games or the ChCht in Deadlock II. These characters are often credited with a hive mind, a common misconception about ant colonies.[203]
+

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+Fra Angelico (born Guido di Pietro; c. 1395[2] – February 18, 1455) was an Italian painter of the Early Renaissance, described by Vasari in his Lives of the Artists as having "a rare and perfect talent".[3] He earned his reputation primarily for with the series of frescoes he made for his own friary, San Marco, in Florence.[4]
+
+He was known to contemporaries as Fra Giovanni da Fiesole (Brother John of Fiesole) and Fra Giovanni Angelico (Angelic Brother John). In modern Italian he is called Beato Angelico (Blessed Angelic One);[5] the common English name Fra Angelico means the "Angelic friar".
+
+In 1982, Pope John Paul II proclaimed his beatification[6] in recognition of the holiness of his life, thereby making the title of "Blessed" official. Fiesole is sometimes misinterpreted as being part of his formal name, but it was merely the name of the town where he took his vows as a Dominican friar,[7] and was used by contemporaries to separate him from others who were also known as Fra Giovanni. He is listed in the Roman Martyrology[8] as Beatus Ioannes Faesulanus, cognomento Angelicus—"Blessed Giovanni of Fiesole, surnamed 'the Angelic' ".
+
+Vasari wrote of Fra Angelico that "it is impossible to bestow too much praise on this holy father, who was so humble and modest in all that he did and said and whose pictures were painted with such facility and piety."[3]
+
+Fra Angelico was born Guido di Pietro at Rupecanina[9] in the Tuscan area of Mugello near Fiesole towards the end of the 14th century. Nothing is known of his parents. He was baptized Guido or Guidolino.  The earliest recorded document concerning Fra Angelico dates from October 17, 1417 when he joined a religious confraternity or guild at the Carmine Church, still under the name of Guido di Pietro.  This record reveals that he was already a painter, a fact that is subsequently confirmed by two records of payment to Guido di Pietro in January and February 1418 for work done in the church of Santo Stefano del Ponte.[10]  The first record of Angelico as a friar dates from 1423, when he is first referred to as Fra Giovanni (Friar John), following the custom of those entering one of the older religious orders of taking a new name.[11]  He was a member of the local community at Fiesole, not far from Florence, of the Dominican Order; one of the medieval Orders belonging to a category known as mendicant Orders because they generally lived not from the income of estates but from begging or donations. Fra, a contraction of frater (Latin for 'brother'), is a conventional title for a mendicant friar.
+
+According to Vasari, Fra Angelico initially received training as an illuminator, possibly working with his older brother Benedetto who was also a Dominican and an illuminator. The former Dominican convent of San Marco in Florence, now a state museum, holds several manuscripts that are thought to be entirely or partly by his hand.[3] The painter Lorenzo Monaco may have contributed to his art training, and the influence of the Sienese school is discernible in his work. He also trained with master Varricho in Milan[12] He had several important charges in the convents he lived in, but this did not limit his art, which very soon became famous.  According to Vasari, the first paintings of this artist were an altarpiece and a painted screen for the Charterhouse (Carthusian monastery) of Florence; none such exist there now.[3]
+
+From 1408 to 1418, Fra Angelico was at the Dominican friary of Cortona, where he painted frescoes, now mostly destroyed, in the Dominican Church and may have been assistant to Gherardo Starnina or a follower of his.[13] Between 1418 and 1436 he was at the convent of Fiesole, where he also executed a number of frescoes for the church and the Altarpiece, which was deteriorated but has since been restored. A predella of the Altarpiece remains intact and is conserved in the National Gallery, London, and is a great example of Fra Angelico's ability. It shows Christ in Glory surrounded by more than 250 figures, including beatified Dominicans. In this period he painted some of his masterpieces including a version of  The Madonna of Humility, well preserved and property of the Thyssen-Bornemisza Museum but on loan to the MNAC of Barcelona, an Annunciation along with a Madonna of the Pomegranate, at the Prado Museum.
+
+In 1436, Fra Angelico was one of a number of the friars from Fiesole who moved to the newly built convent or friary of San Marco in Florence. This was an important move which put him in the centre of artistic activity of the region and brought about the patronage of Cosimo de' Medici, one of the wealthiest and most powerful members of the city's governing authority (or "Signoria") and founder of the dynasty that would dominate Florentine politics for much of the Renaissance. Cosimo had a cell reserved for himself at the friary in order that he might retreat from the world. 
+It was, according to Vasari, at Cosimo's urging that Fra Angelico set about the task of decorating the convent, including the magnificent fresco of the Chapter House, the often-reproduced Annunciation at the top of the stairs leading to the cells, the Maesta (or Coronation of the Madonna) with Saints (cell 9) and the many other devotional frescoes, of smaller format but remarkable luminous quality, depicting aspects of the Life of Christ that adorn the walls of each cell.[3]
+
+In 1439 Fra Angelico completed one of his most famous works, the San Marco Altarpiece at Florence. The result was unusual for its time. Images of the enthroned Madonna and Child surrounded by saints were common, but they usually depicted a setting that was clearly heaven-like, in which saints and angels hovered about as divine presences rather than people. But in this instance, the saints stand squarely within the space, grouped in a natural way as if they were able to converse about the shared experience of witnessing the Virgin in glory. Paintings such as this, known as Sacred Conversations, were to become the major commissions of Giovanni Bellini, Perugino and Raphael.[14]
+
+In 1445 Pope Eugene IV summoned him to Rome to paint the frescoes of the Chapel of the Holy Sacrament at St Peter's, later demolished by Pope Paul III. Vasari claims that at this time Fra Angelico was offered the Archbishopric of Florence by Pope Nicholas V, and that he refused it, recommending another friar for the position. The story seems possible and even likely. However, if Vasari's date is correct, then the pope must have been Eugene IV and not Nicholas, who was elected Pope only on 6 March 1447. Moreover, the archbishop in 1446–1459 was the Dominican Antoninus of Florence (Antonio Pierozzi), canonized by Pope Adrian VI in 1523. In 1447 Fra Angelico was in Orvieto with his pupil, Benozzo Gozzoli, executing works for the Cathedral. Among his other pupils were Zanobi Strozzi.[15]
+
+From 1447 to 1449 Fra Angelico was back at the Vatican, designing the frescoes for the Niccoline Chapel for Nicholas V. The scenes from the lives of the two martyred deacons of the Early Christian Church, St. Stephen and St. Lawrence may have been executed wholly or in part by assistants. The small chapel, with its brightly frescoed walls and gold leaf decorations gives the impression of a jewel box.  From 1449 until 1452, Fra Angelico returned to his old convent of Fiesole, where he was the Prior.[3][16]
+
+In 1455, Fra Angelico died while staying at a Dominican convent in Rome, perhaps on an order to work on Pope Nicholas' chapel. He was buried in the church of Santa Maria sopra Minerva.[3][16][17]
+
+When singing my praise, don't liken my talents to those of Apelles.  Say, rather, that, in the name of Christ, I gave all I had to the poor.
+
+The deeds that count on Earth are not the ones that count in Heaven.
+
+I, Giovanni, am the flower of Tuscany.
+
+The English writer and critic William Michael Rossetti wrote of the friar:
+
+From various accounts of Fra Angelico’s life, it is possible to gain some sense of why he was deserving of canonization. He led the devout and ascetic life of a Dominican friar, and never rose above that rank; he followed the dictates of the order in caring for the poor; he was always good-humored. All of his many paintings were of divine subjects, and it seems that he never altered or retouched them, perhaps from a religious conviction that, because his paintings were divinely inspired, they should retain their original form. He was wont to say that he who illustrates the acts of Christ should be with Christ. It is averred that he never handled a brush without fervent prayer and he wept when he painted a Crucifixion. The Last Judgment and the Annunciation were two of the subjects he most frequently treated.[18][16]
+
+Pope John Paul II beatified Fra Angelico on October 3, 1982, and in 1984 declared him patron of Catholic artists.[6]
+
+Angelico was reported to say "He who does Christ's work must stay with Christ always". This motto earned him the epithet "Blessed Angelico", because of the perfect integrity of his life and the almost divine beauty of the images he painted, to a superlative extent those of the Blessed Virgin Mary.
+
+Fra Angelico was working at a time when the style of painting was in a state of change. This process of change had begun a hundred years previous with the works of Giotto and several of his contemporaries, notably Giusto de' Menabuoi, both of whom had created their major works in Padua, although Giotto was trained in Florence by the great Gothic artist, Cimabue, and painted a fresco cycle of St Francis in the Bardi Chapel in the Basilica di Santa Croce. Giotto had many enthusiastic followers, who imitated his style in fresco, some of them, notably the Lorenzetti, achieving great success.[14]
+
+The patrons of these artists were most often monastic establishments or wealthy families endowing a church. Because the paintings often had devotional purpose, the clients tended to be conservative. Frequently, it would seem, the wealthier the client, the more conservative the painting. There was a very good reason for this. The paintings that were commissioned made a statement about the patron. Thus the more gold leaf  it displayed, the more it spoke to the patron's glory. The other valuable commodities in the paint-box were lapis lazuli and vermilion. Paint made from these colours did not lend itself to a tonal treatment. The azure blue made of powdered lapis lazuli went on flat, the depth and brilliance of colour being, like the gold leaf, a sign of the patron's ability to provide well. For these reasons, altarpieces are often much more conservatively painted than frescoes, which were often of almost life-sized figures and relied upon a stage-set quality rather than lavish display in order to achieve effect.[19]
+
+Fra Angelico was the contemporary of Gentile da Fabriano. Gentile's altarpiece of the Adoration of the Magi, 1423, in the Uffizi is regarded as one of the greatest works of the style known as International Gothic. At the time it was painted, another young artist, known as Masaccio, was working on the frescoes for the Brancacci Chapel at the church of the Carmine. Masaccio had fully grasped the implications of the art of Giotto. Few painters in Florence saw his sturdy, lifelike and emotional figures and were not affected by them. His work partner was an older painter, Masolino, of the same generation as Fra Angelico. Masaccio died at 27, leaving the work unfinished.[14]
+
+The works of Fra Angelico reveal elements that are both conservatively Gothic and progressively Renaissance. In the altarpiece of the Coronation of the Virgin, painted for the Florentine church of Santa Maria Novella, are all the elements that a very expensive altarpiece of the 14th century was expected to provide; a precisely tooled gold background, much azure, much vermilion and an obvious display of arsenic green. The workmanship of the gilded haloes and gold-edged robes is exquisite and all very Gothic. What makes this a Renaissance painting, as against Gentile da Fabriano's masterpiece, is the solidity, the three-dimensionality and naturalism of the figures and the realistic way in which their garments hang or drape around them. Even though it is clouds these figures stand upon, and not the earth, they do so with weight.[14]
+
+The series of frescoes that Fra Angelico painted for the Dominican friars at San Marcos realise the advancements made by Masaccio and carry them further. Away from the constraints of wealthy clients and the limitations of panel painting, Fra Angelico was able to express his deep reverence for his God and his knowledge and love of humanity. The meditational frescoes in the cells of the convent have a quieting quality about them. They are humble works in simple colours. There is more mauvish-pink than there is red, and the brilliant and expensive blue is almost totally lacking. In its place is dull green and the black and white of Dominican robes. There is nothing lavish, nothing to distract from the spiritual experiences of the humble people who are depicted within the frescoes. Each one has the effect of bringing an incident of the life of Christ into the presence of the viewer. They are like windows into a parallel world. These frescoes remain a powerful witness to the piety of the man who created them.[14]
+Vasari relates that Cosimo de' Medici seeing these works, inspired Fra Angelico to create a large Crucifixion scene with many saints for the Chapter House. As with the other frescoes, the wealthy patronage did not influence the Friar's artistic expression with displays of wealth.[3]
+
+Masaccio ventured into perspective with his creation of a realistically painted niche at Santa Maria Novella. Subsequently, Fra Angelico demonstrated an understanding of linear perspective particularly in his Annunciation paintings set inside the sort of arcades that Michelozzo and Brunelleschi created at San’ Marco's and the square in front of it.[14]
+
+When Fra Angelico and his assistants went to the Vatican to decorate the chapel of Pope Nicholas, the artist was again confronted with the need to please the very wealthiest of clients. In consequence, walking into the small chapel is like stepping into a jewel box. The walls are decked with the brilliance of colour and gold that one sees in the most lavish creations of the Gothic painter Simone Martini at the Lower Church of St Francis of Assisi, a hundred years earlier. Yet Fra Angelico has succeeded in creating designs which continue to reveal his own preoccupation with humanity, with humility and with piety. The figures, in their lavish gilded robes, have the sweetness and gentleness for which his works are famous. According to Vasari:
+
+In their bearing and expression, the saints painted by Fra Angelico come nearer to the truth than the figures done by any other artist.[3]
+
+It is probable that much of the actual painting was done by his assistants to his design. Both Benozzo Gozzoli and Gentile da Fabriano were highly accomplished painters. Benozzo took his art further towards the fully developed Renaissance style with his expressive and lifelike portraits in his masterpiece depicting the Journey of the Magi, painted in the Medici's private chapel at their palazzo.[20]
+
+Through Fra Angelico's pupil Benozzo Gozzoli's careful portraiture and technical expertise in the art of fresco we see a link to Domenico Ghirlandaio, who in turn painted extensive schemes for the wealthy patrons of Florence, and through Ghirlandaio to his pupil Michelangelo and the High Renaissance.
+
+Apart from the lineal connection, superficially there may seem little to link the humble priest with his sweetly pretty Madonnas and timeless Crucifixions to the dynamic expressions of Michelangelo's larger-than-life creations. But both these artists received their most important commissions from the wealthiest and most powerful of all patrons, the Vatican.
+
+When Michelangelo took up the Sistine Chapel commission, he was working within a space that had already been extensively decorated by other artists. Around the walls the Life of Christ and Life of Moses were depicted by a range of artists including his teacher Ghirlandaio, Raphael's teacher Perugino and Botticelli. They were works of large scale and exactly the sort of lavish treatment to be expected in a Vatican commission, vying with each other in complexity of design, number of figures, elaboration of detail and skillful use of gold leaf. Above these works stood a row of painted Popes in brilliant brocades and gold tiaras. None of these splendours have any place in the work which Michelangelo created. Michelangelo, when asked by Pope Julius II to ornament the robes of the Apostles in the usual way, responded that they were very poor men.[14]
+
+Within the cells of San’Marco, Fra Angelico had demonstrated that painterly skill and the artist's personal interpretation were sufficient to create memorable works of art, without the expensive trappings of blue and gold. In the use of the unadorned fresco technique, the clear bright pastel colours, the careful arrangement of a few significant figures and the skillful use of expression, motion and gesture, Michelangelo showed himself to be the artistic descendant of Fra Angelico. Frederick Hartt describes Fra Angelico as "prophetic of the mysticism" of painters such as Rembrandt, El Greco and Zurbarán.[14]
+
+Rome
+
+Cortona
+
+Fiesole
+
+Florence, Santa Trinita
+
+Florence, Santa Maria degli Angeli
+
+Florence, Santa Maria Novella
+
+Each cell is decorated with a fresco which matches in size and shape the single round-headed window beside it. The frescoes are apparently for contemplative purpose. They have a pale, serene, unearthly beauty. Many of Fra Angelico's finest and most reproduced works are among them. There are, particularly in the inner row of cells, some of less inspiring quality and of more repetitive subject, perhaps completed by assistants.[14] Many pictures include Dominican saints as witnesses of scene each in one of the nine traditional prayer postures depicted in De Modo Orandi. The friar using the cell could place himself in the scene.
+
+Orvieto Cathedral
+
+Three segments of the ceiling in the Cappella Nuova, with the assistance of Benozzo Gozzoli.
+
+Niccoline Chapel
+
+The Chapel of Pope Nicholas V, at the Vatican, was probably painted with much assistance from Benozzo Gozzoli and Gentile da Fabriano. The entire surface of wall and ceiling is sumptuously painted. There is much gold leaf for borders and decoration, and a great use of brilliant blue made from lapis lazuli.
+
+Worldwide press coverage reported in November 2006 that two missing masterpieces by Fra Angelico had turned up, having hung in the spare room of the late Jean Preston, in her terrace house in Oxford, England. Her father had bought them for £100 each in the 1960s then bequeathed them to her when he died.[23] Preston, an expert medievalist, recognised them as being high quality Florentine renaissance, but did not realize that they were works by Fra Angelico until they were identified in 2005 by Michael Liversidge of Bristol University.[24]  There was almost no demand at all for medieval art during the 1960s and no dealers showed any interest, so Preston's father bought them almost as an afterthought along with some manuscripts. Coincidentally the manuscripts turned out to be high quality Victorian forgeries by The Spanish Forger.[citation needed]  The paintings are two of eight side panels of a large altarpiece painted in 1439 for Fra Angelico's monastery at San Marco, which was later split up by Napoleon's army. While the centre section is still at the monastery, the other six small panels are in German and US museums. These two panels were presumed lost forever. The Italian Government had hoped to purchase them but they were outbid at auction on 20 April 2007 by a private collector for £1.7M.[23] Both panels are now restored and exhibited in the San Marco Museum in Florence.

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+A fraction (from Latin fractus, "broken") represents a part of a whole or, more generally, any number of equal parts. When spoken in everyday English, a fraction describes how many parts of a certain size there are, for example, one-half, eight-fifths, three-quarters. A common, vulgar, or simple fraction (examples: 
+
+
+
+
+
+
+1
+2
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}}
+
+ and 
+
+
+
+
+
+
+17
+3
+
+
+
+
+
+{\displaystyle {\tfrac {17}{3}}}
+
+) consists of a numerator displayed above a line (or before a slash), and a non-zero denominator, displayed below (or after) that line. Numerators and denominators are also used in fractions that are not common, including compound fractions, complex fractions, and mixed numerals.
+
+In positive common fractions, the numerator and denominator are natural numbers. The numerator represents a number of equal parts, and the denominator indicates how many of those parts make up a unit or a whole. The denominator cannot be zero because zero parts can never make up a whole. For example, in the fraction 3⁄4, the numerator, 3, tells us that the fraction represents 3 equal parts, and the denominator, 4, tells us that 4 parts make up a whole. The picture to the right illustrates 
+
+
+
+
+
+
+3
+4
+
+
+
+
+
+{\displaystyle {\tfrac {3}{4}}}
+
+or ​3⁄4 of a cake.
+
+A common fraction is a numeral which represents a rational number. That same number can also be represented as a decimal, a percent, or with a negative exponent. For example, 0.01, 1%, and 10−2 all equal the fraction 1/100. An integer such as the number 7 can be thought of as having an implicit denominator of one: 7 equals 7/1.
+
+Other uses for fractions are to represent ratios and division.[1] Thus the fraction 3/4 is also used to represent the ratio 3:4 (the ratio of the part to the whole) and the division 3 ÷ 4 (three divided by four). The non-zero denominator in the case using a fraction to represent division is an example of the rule that division by zero is undefined.
+
+We can also write negative fractions, which represent the opposite of a positive fraction. For example, if 1/2 represents a half dollar profit, then −1/2 represents a half dollar loss. Because of the rules of division of signed numbers, which require that, for example, negative divided by positive is negative, −1/2, –1/2 and 1/–2, all represent the same fraction, negative one-half. Because a negative divided by a negative produces a positive, –1/–2 represents positive one-half.
+
+In mathematics the set of all numbers that can be expressed in the form a/b, where a and b are integers and b is not zero, is called the set of rational numbers and is represented by the symbol Q, which stands for quotient. The test for a number being a rational number is that it can be written in that form (i.e., as a common fraction). However, the word fraction is also used to describe mathematical expressions that are not rational numbers, for example algebraic fractions (quotients of algebraic expressions), and expressions that contain irrational numbers, such as √2/2 (see square root of 2) and π/4 (see proof that π is irrational).
+
+In a fraction, the number of equal parts being described is the numerator (from Latin numerātor, "counter" or "numberer"), and the type or variety of the parts is the denominator (from Latin dēnōminātor, "thing that names or designates").[2] As an example, the fraction ​8⁄5 amounts to eight parts, each of which is of the type named "fifth". In terms of division, the numerator corresponds to the dividend, and the denominator corresponds to the divisor.
+
+Informally, the numerator and denominator may be distinguished by placement alone but in formal contexts they are usually separated by a fraction bar. The fraction bar may be horizontal (as in 1/3), oblique (as in 2/5), or diagonal (as in ​4⁄9).[3] These marks are respectively known as the horizontal bar; the virgule, slash (US), or stroke (UK); and the fraction bar, solidus, or fraction slash.[n 1] In typography, fractions stacked vertically are also known as "en" or "nut fractions", and diagonal ones as "em" or "mutton fractions", based on whether a fraction with a single-digit numerator and denominator occupies the proportion of a narrow en square, or a wider em square.[3] In traditional typefounding, a piece of type bearing a complete fraction (e.g. 1/2) was known as a "case fraction," while those representing only part of fraction were called "piece fractions."
+
+The denominators of English fractions are generally expressed as ordinal numbers, in the plural if the numerator is not one. (For example, ​2⁄5 and ​3⁄5 are both read as a number of "fifths".) Exceptions include the denominator 2, which is always read "half" or "halves", the denominator 4, which may be alternatively expressed as "quarter"/"quarters" or as "fourth"/"fourths", and the denominator 100, which may be alternatively expressed as "hundredth"/"hundredths" or "percent". When the denominator is 1, it may be expressed in terms of "wholes" but is more commonly ignored, with the numerator read out as a whole number. (For example, 3/1 may be described as "three wholes" or as simply "three".) When the numerator is one, it may be omitted. (For example, "a tenth" or "each quarter".)
+
+The entire fraction may be expressed as a single composition, in which case it is hyphenated, or as a number of fractions with a numerator of one, in which case they are not. (For example, "two-fifths" is the fraction 2/5 and "two fifths" is the same fraction understood as 2 instances of ​1⁄5.) Fractions should always be hyphenated when used as adjectives. Alternatively, a fraction may be described by reading it out as the numerator "over" the denominator, with the denominator expressed as a cardinal number. (For example, 3/1 may also be expressed as "three over one".) The term "over" is used even in the case of solidus fractions, where the numbers are placed left and right of a slash mark. (For example, 1/2 may be read "one-half", "one half", or "one over two".) Fractions with large denominators that are not powers of ten are often rendered in this fashion (e.g., 1/117 as "one over one hundred seventeen") while those with denominators divisible by ten are typically read in the normal ordinal fashion (e.g., 6/1000000 as "six-millionths", "six millionths", or "six one-millionths").
+
+A simple fraction (also known as a common fraction or vulgar fraction) is a rational number written as a/b or 
+
+
+
+
+
+
+a
+b
+
+
+
+
+
+{\displaystyle {\tfrac {a}{b}}}
+
+, where a and b are both integers.[7] As with other fractions, the denominator (b) cannot be zero. Examples include 
+
+
+
+
+
+
+1
+2
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}}
+
+, 
+
+
+
+−
+
+
+
+8
+5
+
+
+
+
+
+{\displaystyle -{\tfrac {8}{5}}}
+
+, 
+
+
+
+
+
+
+
+−
+8
+
+5
+
+
+
+
+
+{\displaystyle {\tfrac {-8}{5}}}
+
+, and 
+
+
+
+
+
+
+8
+
+−
+5
+
+
+
+
+
+
+{\displaystyle {\tfrac {8}{-5}}}
+
+. Simple fractions can be positive or negative, and they can be proper or improper (see below). Compound fractions, complex fractions, mixed numerals, and decimals (see below) are not simple fractions; though, unless irrational, they can be evaluated to a simple fraction.
+
+Common fractions can be classified as either proper or improper. When the numerator and the denominator are both positive, the fraction is called proper if the numerator is less than the denominator, and improper otherwise.[8][9] In general, a common fraction is said to be a proper fraction if the absolute value of the fraction is strictly less than one—that is, if the fraction is greater than −1 and less than 1.[10][11] It is said to be an improper fraction, or sometimes top-heavy fraction,[12] if the absolute value of the fraction is greater than or equal to 1. Examples of proper fractions are 2/3, –3/4, and 4/9; examples of improper fractions are 9/4, –4/3, and 3/3.
+
+The reciprocal of a fraction is another fraction with the numerator and denominator exchanged. The reciprocal of 
+
+
+
+
+
+
+3
+7
+
+
+
+
+
+{\displaystyle {\tfrac {3}{7}}}
+
+, for instance, is 
+
+
+
+
+
+
+7
+3
+
+
+
+
+
+{\displaystyle {\tfrac {7}{3}}}
+
+. The product of a fraction and its reciprocal is 1, hence the reciprocal is the multiplicative inverse of a fraction. The reciprocal of a proper fraction is improper, and the reciprocal of an improper fraction not equal to 1 (that is, numerator and denominator are not equal) is a proper fraction.
+
+When the numerator and denominator of a fraction are equal (
+
+
+
+
+
+
+7
+7
+
+
+
+
+
+{\displaystyle {\tfrac {7}{7}}}
+
+, for example), its value is 1, and the fraction therefore is improper. Its reciprocal also has the value 1, and is improper, too.
+
+Any integer can be written as a fraction with the number one as denominator. For example, 17 can be written as 
+
+
+
+
+
+
+17
+1
+
+
+
+
+
+{\displaystyle {\tfrac {17}{1}}}
+
+, where 1 is sometimes referred to as the invisible denominator. Therefore, every fraction or integer, except for zero, has a reciprocal. The reciprocal of 17 is 
+
+
+
+
+
+
+1
+17
+
+
+
+
+
+{\displaystyle {\tfrac {1}{17}}}
+
+.
+
+A ratio is a relationship between two or more numbers that can be sometimes expressed as a fraction. Typically, a number of items are grouped and compared in a ratio, specifying numerically the relationship between each group. Ratios are expressed as "group 1 to group 2 ... to group n". For example, if a car lot had 12 vehicles, of which
+
+then the ratio of red to white to yellow cars is 6 to 2 to 4. The ratio of yellow cars to white cars is 4 to 2 and may be expressed as 4:2 or 2:1.
+
+A ratio is often converted to a fraction when it is expressed as a ratio to the whole. In the above example, the ratio of yellow cars to all the cars on the lot is 4:12 or 1:3. We can convert these ratios to a fraction and say that 4/12 of the cars or ⅓ of the cars in the lot are yellow. Therefore, if a person randomly chose one car on the lot, then there is a one in three chance or probability that it would be yellow.
+
+A decimal fraction is a fraction whose denominator is not given explicitly, but is understood to be an integer power of ten. Decimal fractions are commonly expressed using decimal notation in which the implied denominator is determined by the number of digits to the right of a decimal separator, the appearance of which (e.g., a period, a raised period (•), a comma) depends on the locale (for examples, see decimal separator). Thus for 0.75 the numerator is 75 and the implied denominator is 10 to the second power, viz. 100, because there are two digits to the right of the decimal separator. In decimal numbers greater than 1 (such as 3.75), the fractional part of the number is expressed by the digits to the right of the decimal (with a value of 0.75 in this case). 3.75 can be written either as an improper fraction, 375/100, or as a mixed number, 
+
+
+
+3
+
+
+
+75
+100
+
+
+
+
+
+{\displaystyle 3{\tfrac {75}{100}}}
+
+.
+
+Decimal fractions can also be expressed using scientific notation with negative exponents, such as 6.023×10−7, which represents 0.0000006023. The 10−7 represents a denominator of 107. Dividing by 107 moves the decimal point 7 places to the left.
+
+Decimal fractions with infinitely many digits to the right of the decimal separator represent an infinite series. For example, 1/3 = 0.333... represents the infinite series 3/10 + 3/100 + 3/1000 + ... .
+
+Another kind of fraction is the percentage (Latin per centum meaning "per hundred", represented by the symbol %), in which the implied denominator is always 100. Thus, 51% means 51/100. Percentages greater than 100 or less than zero are treated in the same way, e.g. 311% equals 311/100, and −27% equals −27/100.
+
+The related concept of permille or parts per thousand (ppt) has an implied denominator of 1000, while the more general parts-per notation, as in 75 parts per million (ppm), means that the proportion is 75/1,000,000.
+
+Whether common fractions or decimal fractions are used is often a matter of taste and context. Common fractions are used most often when the denominator is relatively small. By mental calculation, it is easier to multiply 16 by 3/16 than to do the same calculation using the fraction's decimal equivalent (0.1875). And it is more accurate to multiply 15 by 1/3, for example, than it is to multiply 15 by any decimal approximation of one third. Monetary values are commonly expressed as decimal fractions with denominator 100, i.e., with two decimals, for example $3.75. However, as noted above, in pre-decimal British currency, shillings and pence were often given the form (but not the meaning) of a fraction, as, for example 3/6 (read "three and six") meaning 3 shillings and 6 pence, and having no relationship to the fraction 3/6.
+
+A mixed numeral (also called a mixed fraction or mixed number) is a traditional denotation of the sum of a non-zero integer and a proper fraction (having the same sign). It is used primarily in measurement: 
+
+
+
+2
+
+
+
+3
+16
+
+
+
+
+
+{\displaystyle 2{\tfrac {3}{16}}}
+
+inches, for example. Scientific measurements almost invariably use decimal notation rather than mixed numbers. The sum is implied without the use of a visible operator such as the appropriate "+". For example, in referring to two entire cakes and three quarters of another cake, the numerals denoting the integer part and the fractional part of the cakes are written next to each other as 
+
+
+
+2
+
+
+
+3
+4
+
+
+
+
+
+{\displaystyle 2{\tfrac {3}{4}}}
+
+instead of the unambiguous notation 
+
+
+
+2
++
+
+
+
+3
+4
+
+
+
+.
+
+
+{\displaystyle 2+{\tfrac {3}{4}}.}
+
+ Negative mixed numerals, as in 
+
+
+
+−
+2
+
+
+
+3
+4
+
+
+
+
+
+{\displaystyle -2{\tfrac {3}{4}}}
+
+, are treated like 
+
+
+
+−
+(
+2
++
+
+
+
+3
+4
+
+
+
+)
+.
+
+
+{\displaystyle -(2+{\tfrac {3}{4}}).}
+
+ Any such sum of a whole plus a part can be converted to an improper fraction by applying the rules of adding unlike quantities.
+
+This tradition is, formally, in conflict with the notation in algebra where adjacent factors, without an explicit infix operator, denote a product. When two algebraic expressions are written next to each other, the operation of multiplication is implied by this general rule: 
+
+
+
+2
+x
+
+
+{\displaystyle 2x}
+
+ always means the product of 
+
+
+
+2
+
+
+{\displaystyle 2}
+
+ and 
+
+
+
+x
+
+
+{\textstyle x}
+
+, even if the value of 
+
+
+
+x
+
+
+{\displaystyle x}
+
+ is a fraction. The expression 
+
+
+
+2
+
+
+
+b
+c
+
+
+
+
+
+{\displaystyle 2{\tfrac {b}{c}}}
+
+ for example is not a mixed number; instead, multiplication is expressly required, where 
+
+
+
+2
+
+
+
+b
+c
+
+
+
+=
+2
+⋅
+
+
+
+b
+c
+
+
+
+.
+
+
+{\displaystyle 2{\tfrac {b}{c}}=2\cdot {\tfrac {b}{c}}.}
+
+For better readability, the multiplication is sometimes made explicit or parentheses are added. So, 
+
+
+
+2
+
+
+
+b
+c
+
+
+
+
+
+{\displaystyle 2{\tfrac {b}{c}}}
+
+ may be written as
+
+An improper fraction can be converted to a mixed number as follows:
+
+An Egyptian fraction is the sum of distinct positive unit fractions, for example 
+
+
+
+
+
+
+1
+2
+
+
+
++
+
+
+
+1
+3
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}+{\tfrac {1}{3}}}
+
+. This definition derives from the fact that the ancient Egyptians expressed all fractions except 
+
+
+
+
+
+
+1
+2
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}}
+
+, 
+
+
+
+
+
+
+2
+3
+
+
+
+
+
+{\displaystyle {\tfrac {2}{3}}}
+
+ and 
+
+
+
+
+
+
+3
+4
+
+
+
+
+
+{\displaystyle {\tfrac {3}{4}}}
+
+ in this manner. Every positive rational number can be expanded as an Egyptian fraction. For example, 
+
+
+
+
+
+
+5
+7
+
+
+
+
+
+{\displaystyle {\tfrac {5}{7}}}
+
+ can be written as 
+
+
+
+
+
+
+1
+2
+
+
+
++
+
+
+
+1
+6
+
+
+
++
+
+
+
+1
+21
+
+
+
+.
+
+
+{\displaystyle {\tfrac {1}{2}}+{\tfrac {1}{6}}+{\tfrac {1}{21}}.}
+
+ Any positive rational number can be written as a sum of unit fractions in infinitely many ways. Two ways to write 
+
+
+
+
+
+
+13
+17
+
+
+
+
+
+{\displaystyle {\tfrac {13}{17}}}
+
+ are 
+
+
+
+
+
+
+1
+2
+
+
+
++
+
+
+
+1
+4
+
+
+
++
+
+
+
+1
+68
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}+{\tfrac {1}{4}}+{\tfrac {1}{68}}}
+
+ and 
+
+
+
+
+
+
+1
+3
+
+
+
++
+
+
+
+1
+4
+
+
+
++
+
+
+
+1
+6
+
+
+
++
+
+
+
+1
+68
+
+
+
+
+
+{\displaystyle {\tfrac {1}{3}}+{\tfrac {1}{4}}+{\tfrac {1}{6}}+{\tfrac {1}{68}}}
+
+.
+
+The notions ‘complex fraction’ and ‘compound fraction’ are both outdated[13] and nowadays used in no well-defined manner, partly even taken synonymously for each other[14] or for mixed numerals.[15] They lost their meaning as technical terms and the attributes "complex" and "compound" tend to be used in their every day meaning of "consisting of parts".
+
+In a complex fraction, either the numerator, or the denominator, or both, is a fraction or a mixed number,[16][17] corresponding to division of fractions. For example, 
+
+
+
+
+
+
+
+1
+2
+
+
+
+
+1
+3
+
+
+
+
+
+
+{\displaystyle {\frac {\tfrac {1}{2}}{\tfrac {1}{3}}}}
+
+ and 
+
+
+
+
+
+
+12
+
+
+
+3
+4
+
+
+
+
+26
+
+
+
+
+{\displaystyle {\frac {12{\tfrac {3}{4}}}{26}}}
+
+ are complex fractions. To reduce a complex fraction to a simple fraction, treat the longest fraction line as representing division. For example:
+
+If, in a complex fraction, there is no unique way to tell which fraction lines takes precedence, then this expression is improperly formed, because of ambiguity. So 5/10/20/40 is not a valid mathematical expression, because of multiple possible interpretations, e.g. as
+
+A compound fraction is a fraction of a fraction, or any number of fractions connected with the word of,[16][17] corresponding to multiplication of fractions. To reduce a compound fraction to a simple fraction, just carry out the multiplication (see the section on multiplication). For example, 
+
+
+
+
+
+
+3
+4
+
+
+
+
+
+{\displaystyle {\tfrac {3}{4}}}
+
+ of 
+
+
+
+
+
+
+5
+7
+
+
+
+
+
+{\displaystyle {\tfrac {5}{7}}}
+
+ is a compound fraction, corresponding to 
+
+
+
+
+
+
+3
+4
+
+
+
+×
+
+
+
+5
+7
+
+
+
+=
+
+
+
+15
+28
+
+
+
+
+
+{\displaystyle {\tfrac {3}{4}}\times {\tfrac {5}{7}}={\tfrac {15}{28}}}
+
+. The terms compound fraction and complex fraction are closely related and sometimes one is used as a synonym for the other. (For example, the compound fraction 
+
+
+
+
+
+
+3
+4
+
+
+
+×
+
+
+
+5
+7
+
+
+
+
+
+{\displaystyle {\tfrac {3}{4}}\times {\tfrac {5}{7}}}
+
+ is equivalent to the complex fraction 
+
+
+
+
+
+
+
+3
+
+/
+
+4
+
+
+7
+
+/
+
+5
+
+
+
+
+
+
+{\displaystyle {\tfrac {3/4}{7/5}}}
+
+.)
+
+Like whole numbers, fractions obey the commutative, associative, and distributive laws, and the rule against division by zero.
+
+Multiplying the numerator and denominator of a fraction by the same (non-zero) number results in a fraction that is equivalent to the original fraction. This is true because for any non-zero number 
+
+
+
+n
+
+
+{\displaystyle n}
+
+, the fraction 
+
+
+
+
+
+
+n
+n
+
+
+
+=
+1
+
+
+{\displaystyle {\tfrac {n}{n}}=1}
+
+. Therefore, multiplying by 
+
+
+
+
+
+
+n
+n
+
+
+
+
+
+{\displaystyle {\tfrac {n}{n}}}
+
+is equivalent to multiplying by one, and any number multiplied by one has the same value as the original number. By way of an example, start with the fraction 
+
+
+
+
+
+
+1
+2
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}}
+
+. When the numerator and denominator are both multiplied by 2, the result is 
+
+
+
+
+
+
+2
+4
+
+
+
+
+
+{\displaystyle {\tfrac {2}{4}}}
+
+, which has the same value (0.5) as 
+
+
+
+
+
+
+1
+2
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}}
+
+. To picture this visually, imagine cutting a cake into four pieces; two of the pieces together (
+
+
+
+
+
+
+2
+4
+
+
+
+
+
+{\displaystyle {\tfrac {2}{4}}}
+
+) make up half the cake (
+
+
+
+
+
+
+1
+2
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}}
+
+).
+
+Dividing the numerator and denominator of a fraction by the same non-zero number will also yield an equivalent fraction. If the numerator and the denominator of a fraction are both divisible by a number (called a factor) greater than 1, then the fraction can be reduced to an equal fraction with a smaller numerator and a smaller denominator. To do this, the greatest common factor is identified, and both the numerator and the denominator are divided by this factor. For example, if both the numerator and the denominator of the fraction 
+
+
+
+
+
+
+a
+b
+
+
+
+
+
+{\displaystyle {\tfrac {a}{b}}}
+
+are divisible by 
+
+
+
+c
+,
+
+
+{\displaystyle c,}
+
+ then they can be written as 
+
+
+
+a
+=
+c
+d
+
+
+{\displaystyle a=cd}
+
+ and 
+
+
+
+b
+=
+c
+e
+,
+
+
+{\displaystyle b=ce,}
+
+ so the fraction becomes 
+
+
+
+
+
+
+
+c
+d
+
+
+c
+e
+
+
+
+
+
+
+{\displaystyle {\tfrac {cd}{ce}}}
+
+, which can be reduced by dividing both the numerator and denominator by 
+
+
+
+c
+
+
+{\displaystyle c}
+
+ to give the reduced fraction 
+
+
+
+
+
+
+d
+e
+
+
+
+.
+
+
+{\displaystyle {\tfrac {d}{e}}.}
+
+If the numerator and the denominator do not share any factor greater than 1, then the fraction is said to be irreducible, in lowest terms, or in simplest terms. For example, 
+
+
+
+
+
+
+3
+9
+
+
+
+
+
+{\displaystyle {\tfrac {3}{9}}}
+
+is not in lowest terms because both 3 and 9 can be exactly divided by 3. In contrast, 
+
+
+
+
+
+
+3
+8
+
+
+
+
+
+{\displaystyle {\tfrac {3}{8}}}
+
+ is in lowest terms—the only positive integer that goes into both 3 and 8 evenly is 1.
+
+Using these rules, we can show that 
+
+
+
+
+
+
+5
+10
+
+
+
+
+
+{\displaystyle {\tfrac {5}{10}}}
+
+= 
+
+
+
+
+
+
+1
+2
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}}
+
+= 
+
+
+
+
+
+
+10
+20
+
+
+
+
+
+{\displaystyle {\tfrac {10}{20}}}
+
+= 
+
+
+
+
+
+
+50
+100
+
+
+
+
+
+{\displaystyle {\tfrac {50}{100}}}
+
+.
+
+As another example, since the greatest common divisor of 63 and 462 is 21, the fraction 
+
+
+
+
+
+
+63
+462
+
+
+
+
+
+{\displaystyle {\tfrac {63}{462}}}
+
+can be reduced to lowest terms by dividing the numerator and denominator by 21:
+
+The Euclidean algorithm gives a method for finding the greatest common divisor of any two positive integers.
+
+Comparing fractions with the same positive denominator yields the same result as comparing the numerators:
+
+If the equal denominators are negative, then the opposite result of comparing the numerators holds for the fractions:
+
+If two positive fractions have the same numerator, then the fraction with the smaller denominator is the larger number. When a whole is divided into equal pieces, if fewer equal pieces are needed to make up the whole, then each piece must be larger. When two positive fractions have the same numerator, they represent the same number of parts, but in the fraction with the smaller denominator, the parts are larger.
+
+One way to compare fractions with different numerators and denominators is to find a common denominator. To compare 
+
+
+
+
+
+
+a
+b
+
+
+
+
+
+{\displaystyle {\tfrac {a}{b}}}
+
+ and 
+
+
+
+
+
+
+c
+d
+
+
+
+
+
+{\displaystyle {\tfrac {c}{d}}}
+
+, these are converted to 
+
+
+
+
+
+
+
+a
+⋅
+d
+
+
+b
+⋅
+d
+
+
+
+
+
+
+{\displaystyle {\tfrac {a\cdot d}{b\cdot d}}}
+
+ and 
+
+
+
+
+
+
+
+b
+⋅
+c
+
+
+b
+⋅
+d
+
+
+
+
+
+
+{\displaystyle {\tfrac {b\cdot c}{b\cdot d}}}
+
+ (where the dot signifies multiplication and is an alternative symbol to ×). Then bd is a common denominator and the numerators ad and bc can be compared. It is not necessary to determine the value of the common denominator to compare fractions – one can just compare ad and bc, without evaluating bd, e.g., comparing 
+
+
+
+
+
+
+2
+3
+
+
+
+
+
+{\displaystyle {\tfrac {2}{3}}}
+
+ ? 
+
+
+
+
+
+
+1
+2
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}}
+
+ gives 
+
+
+
+
+
+
+4
+6
+
+
+
+>
+
+
+
+3
+6
+
+
+
+
+
+{\displaystyle {\tfrac {4}{6}}>{\tfrac {3}{6}}}
+
+.
+
+For the more laborious question 
+
+
+
+
+
+
+5
+18
+
+
+
+
+
+{\displaystyle {\tfrac {5}{18}}}
+
+ ? 
+
+
+
+
+
+
+4
+17
+
+
+
+,
+
+
+{\displaystyle {\tfrac {4}{17}},}
+
+ multiply top and bottom of each fraction by the denominator of the other fraction, to get a common denominator, yielding 
+
+
+
+
+
+
+
+5
+×
+17
+
+
+18
+×
+17
+
+
+
+
+
+
+{\displaystyle {\tfrac {5\times 17}{18\times 17}}}
+
+ ? 
+
+
+
+
+
+
+
+18
+×
+4
+
+
+18
+×
+17
+
+
+
+
+
+
+{\displaystyle {\tfrac {18\times 4}{18\times 17}}}
+
+. It is not necessary to calculate 
+
+
+
+18
+×
+17
+
+
+{\displaystyle 18\times 17}
+
+ – only the numerators need to be compared. Since 5×17 (= 85) is greater than 4×18 (= 72), the result of comparing is 
+
+
+
+
+
+
+5
+18
+
+
+
+>
+
+
+
+4
+17
+
+
+
+
+
+{\displaystyle {\tfrac {5}{18}}>{\tfrac {4}{17}}}
+
+.
+
+Because every negative number, including negative fractions, is less than zero, and every positive number, including positive fractions, is greater than zero, it follows that any negative fraction is less than any positive fraction. This allows, together with the above rules, to compare all possible fractions.
+
+The first rule of addition is that only like quantities can be added; for example, various quantities of quarters. Unlike quantities, such as adding thirds to quarters, must first be converted to like quantities as described below: Imagine a pocket containing two quarters, and another pocket containing three quarters; in total, there are five quarters. Since four quarters is equivalent to one (dollar), this can be represented as follows:
+
+To add fractions containing unlike quantities (e.g. quarters and thirds), it is necessary to convert all amounts to like quantities. It is easy to work out the chosen type of fraction to convert to; simply multiply together the two denominators (bottom number) of each fraction. In case of an integer number apply the invisible denominator 
+
+
+
+1.
+
+
+{\displaystyle 1.}
+
+For adding quarters to thirds, both types of fraction are converted to twelfths, thus:
+
+Consider adding the following two quantities:
+
+First, convert 
+
+
+
+
+
+
+3
+5
+
+
+
+
+
+{\displaystyle {\tfrac {3}{5}}}
+
+ into fifteenths by multiplying both the numerator and denominator by three: 
+
+
+
+
+
+
+3
+5
+
+
+
+×
+
+
+
+3
+3
+
+
+
+=
+
+
+
+9
+15
+
+
+
+
+
+{\displaystyle {\tfrac {3}{5}}\times {\tfrac {3}{3}}={\tfrac {9}{15}}}
+
+. Since 
+
+
+
+
+
+
+3
+3
+
+
+
+
+
+{\displaystyle {\tfrac {3}{3}}}
+
+ equals 1, multiplication by 
+
+
+
+
+
+
+3
+3
+
+
+
+
+
+{\displaystyle {\tfrac {3}{3}}}
+
+ does not change the value of the fraction.
+
+Second, convert 
+
+
+
+
+
+
+2
+3
+
+
+
+
+
+{\displaystyle {\tfrac {2}{3}}}
+
+ into fifteenths by multiplying both the numerator and denominator by five: 
+
+
+
+
+
+
+2
+3
+
+
+
+×
+
+
+
+5
+5
+
+
+
+=
+
+
+
+10
+15
+
+
+
+
+
+{\displaystyle {\tfrac {2}{3}}\times {\tfrac {5}{5}}={\tfrac {10}{15}}}
+
+.
+
+Now it can be seen that:
+
+is equivalent to:
+
+This method can be expressed algebraically:
+
+This algebraic method always works, thereby guaranteeing that the sum of simple fractions is always again a simple fraction. However, if the single denominators contain a common factor, a smaller denominator than the product of these can be used. For example, when adding 
+
+
+
+
+
+
+3
+4
+
+
+
+
+
+{\displaystyle {\tfrac {3}{4}}}
+
+ and 
+
+
+
+
+
+
+5
+6
+
+
+
+
+
+{\displaystyle {\tfrac {5}{6}}}
+
+ the single denominators have a common factor 
+
+
+
+2
+,
+
+
+{\displaystyle 2,}
+
+ and therefore, instead of the denominator 24 (4 × 6), the halved denominator 12 may be used, not only reducing the denominator in the result, but also the factors in the numerator.
+
+The smallest possible denominator is given by the least common multiple of the single denominators, which results from dividing the rote multiple by all common factors of the single denominators. This is called the least common denominator.
+
+The process for subtracting fractions is, in essence, the same as that of adding them: find a common denominator, and change each fraction to an equivalent fraction with the chosen common denominator. The resulting fraction will have that denominator, and its numerator will be the result of subtracting the numerators of the original fractions. For instance,
+
+To multiply fractions, multiply the numerators and multiply the denominators. Thus:
+
+To explain the process, consider one third of one quarter. Using the example of a cake, if three small slices of equal size make up a quarter, and four quarters make up a whole, twelve of these small, equal slices make up a whole. Therefore, a third of a quarter is a twelfth. Now consider the numerators. The first fraction, two thirds, is twice as large as one third. Since one third of a quarter is one twelfth, two thirds of a quarter is two twelfth. The second fraction, three quarters, is three times as large as one quarter, so two thirds of three quarters is three times as large as two thirds of one quarter. Thus two thirds times three quarters is six twelfths.
+
+A short cut for multiplying fractions is called "cancellation". Effectively the answer is reduced to lowest terms during multiplication. For example:
+
+A two is a common factor in both the numerator of the left fraction and the denominator of the right and is divided out of both. Three is a common factor of the left denominator and right numerator and is divided out of both.
+
+Since a whole number can be rewritten as itself divided by 1, normal fraction multiplication rules can still apply.
+
+This method works because the fraction 6/1 means six equal parts, each one of which is a whole.
+
+When multiplying mixed numbers, it is considered preferable[citation needed] to convert the mixed number into an improper fraction. For example:
+
+In other words, 
+
+
+
+2
+
+
+
+3
+4
+
+
+
+
+
+{\displaystyle 2{\tfrac {3}{4}}}
+
+ is the same as 
+
+
+
+
+
+
+8
+4
+
+
+
++
+
+
+
+3
+4
+
+
+
+
+
+{\displaystyle {\tfrac {8}{4}}+{\tfrac {3}{4}}}
+
+, making 11 quarters in total (because 2 cakes, each split into quarters makes 8 quarters total) and 33 quarters is 
+
+
+
+8
+
+
+
+1
+4
+
+
+
+
+
+{\displaystyle 8{\tfrac {1}{4}}}
+
+, since 8 cakes, each made of quarters, is 32 quarters in total.
+
+To divide a fraction by a whole number, you may either divide the numerator by the number, if it goes evenly into the numerator, or multiply the denominator by the number. For example, 
+
+
+
+
+
+
+10
+3
+
+
+
+÷
+5
+
+
+{\displaystyle {\tfrac {10}{3}}\div 5}
+
+ equals 
+
+
+
+
+
+
+2
+3
+
+
+
+
+
+{\displaystyle {\tfrac {2}{3}}}
+
+ and also equals 
+
+
+
+
+
+
+10
+
+3
+⋅
+5
+
+
+
+
+=
+
+
+
+10
+15
+
+
+
+
+
+{\displaystyle {\tfrac {10}{3\cdot 5}}={\tfrac {10}{15}}}
+
+, which reduces to 
+
+
+
+
+
+
+2
+3
+
+
+
+
+
+{\displaystyle {\tfrac {2}{3}}}
+
+. To divide a number by a fraction, multiply that number by the reciprocal of that fraction. Thus, 
+
+
+
+
+
+
+1
+2
+
+
+
+÷
+
+
+
+3
+4
+
+
+
+=
+
+
+
+1
+2
+
+
+
+×
+
+
+
+4
+3
+
+
+
+=
+
+
+
+
+1
+⋅
+4
+
+
+2
+⋅
+3
+
+
+
+
+=
+
+
+
+2
+3
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}\div {\tfrac {3}{4}}={\tfrac {1}{2}}\times {\tfrac {4}{3}}={\tfrac {1\cdot 4}{2\cdot 3}}={\tfrac {2}{3}}}
+
+.
+
+To change a common fraction to a decimal, do a long division of the decimal representations of the numerator by the denominator (this is idiomatically also phrased as "divide the denominator into the numerator"), and round the answer to the desired accuracy. For example, to change ¼ to a decimal, divide 
+
+
+
+1.00
+
+
+{\displaystyle 1.00}
+
+ by 
+
+
+
+4
+
+
+{\displaystyle 4}
+
+ ("
+
+
+
+4
+
+
+{\displaystyle 4}
+
+ into 
+
+
+
+1.00
+
+
+{\displaystyle 1.00}
+
+"), to obtain 
+
+
+
+0.25
+
+
+{\displaystyle 0.25}
+
+. To change ⅓ to a decimal, divide 
+
+
+
+1.000...
+
+
+{\displaystyle 1.000...}
+
+ by 
+
+
+
+3
+
+
+{\displaystyle 3}
+
+ ("
+
+
+
+3
+
+
+{\displaystyle 3}
+
+ into 
+
+
+
+1.0000...
+
+
+{\displaystyle 1.0000...}
+
+"), and stop when the desired accuracy is obtained, e.g., at 
+
+
+
+4
+
+
+{\displaystyle 4}
+
+ decimals with 
+
+
+
+0.3333
+
+
+{\displaystyle 0.3333}
+
+. The fraction ¼ can be written exactly with two decimal digits, while the fraction ⅓ cannot be written exactly as a decimal with a finite number of digits. To change a decimal to a fraction, write in the denominator a 
+
+
+
+1
+
+
+{\displaystyle 1}
+
+ followed by as many zeroes as there are digits to the right of the decimal point, and write in the numerator all the digits of the original decimal, just omitting the decimal point. Thus 
+
+
+
+12.3456
+=
+
+
+
+123456
+10000
+
+
+
+.
+
+
+{\displaystyle 12.3456={\tfrac {123456}{10000}}.}
+
+Decimal numbers, while arguably more useful to work with when performing calculations, sometimes lack the precision that common fractions have. Sometimes an infinite repeating decimal is required to reach the same precision. Thus, it is often useful to convert repeating decimals into fractions.
+
+The preferred[by whom?] way to indicate a repeating decimal is to place a bar (known as a vinculum) over the digits that repeat, for example 0.789 = 0.789789789... For repeating patterns where the repeating pattern begins immediately after the decimal point, a simple division of the pattern by the same number of nines as numbers it has will suffice. For example:
+
+In case leading zeros precede the pattern, the nines are suffixed by the same number of trailing zeros:
+
+In case a non-repeating set of decimals precede the pattern (such as 0.1523987), we can write it as the sum of the non-repeating and repeating parts, respectively:
+
+Then, convert both parts to fractions, and add them using the methods described above:
+
+Alternatively, algebra can be used, such as below:
+
+In addition to being of great practical importance, fractions are also studied by mathematicians, who check that the rules for fractions given above are consistent and reliable. Mathematicians define a fraction as an ordered pair 
+
+
+
+(
+a
+,
+b
+)
+
+
+{\displaystyle (a,b)}
+
+of integers 
+
+
+
+a
+
+
+{\displaystyle a}
+
+and 
+
+
+
+b
+≠
+0
+,
+
+
+{\displaystyle b\neq 0,}
+
+ for which the operations addition, subtraction, multiplication, and division are defined as follows:[18]
+
+These definitions agree in every case with the definitions given above; only the notation is different. Alternatively, instead of defining subtraction and division as operations, the "inverse" fractions with respect to addition and multiplication might be defined as:
+
+Furthermore, the relation, specified as
+
+is an equivalence relation of fractions. Each fraction from one equivalence class may be considered as a representative for the whole class, and each whole class may be considered as one abstract fraction. This equivalence is preserved by the above defined operations, i.e., the results of operating on fractions are independent of the selection of representatives from their equivalence class. Formally, for addition of fractions
+
+and similarly for the other operations.
+
+In case of fractions of integers the fractions with 
+
+
+
+(
+a
+,
+b
+)
+
+
+{\displaystyle (a,b)}
+
+coprime are often taken as uniquely determined representatives for their equivalent fractions, which are considered to be the same rational number. This way the fractions of integers make up the field of the rational numbers.
+
+More generally, a and b may be elements of any integral domain R, in which case a fraction is an element of the field of fractions of R. For example, polynomials in one indeterminate, with coefficients from some integral domain D, are themselves an integral domain, call it P. So for a and b elements of P, the generated field of fractions is the field of rational fractions (also known as the field of rational functions).
+
+An algebraic fraction is the indicated quotient of two algebraic expressions. As with fractions of integers, the denominator of an algebraic fraction cannot be zero. Two examples of algebraic fractions are 
+
+
+
+
+
+
+3
+x
+
+
+
+x
+
+2
+
+
++
+2
+x
+−
+3
+
+
+
+
+
+{\displaystyle {\frac {3x}{x^{2}+2x-3}}}
+
+ and 
+
+
+
+
+
+
+x
++
+2
+
+
+
+x
+
+2
+
+
+−
+3
+
+
+
+
+
+{\displaystyle {\frac {\sqrt {x+2}}{x^{2}-3}}}
+
+. Algebraic fractions are subject to the same field properties as arithmetic fractions.
+
+If the numerator and the denominator are polynomials, as in 
+
+
+
+
+
+
+3
+x
+
+
+
+x
+
+2
+
+
++
+2
+x
+−
+3
+
+
+
+
+
+{\displaystyle {\frac {3x}{x^{2}+2x-3}}}
+
+, the algebraic fraction is called a rational fraction (or rational expression). An irrational fraction is one that is not rational, as, for example, one that contains the variable under a fractional exponent or root, as in 
+
+
+
+
+
+
+x
++
+2
+
+
+
+x
+
+2
+
+
+−
+3
+
+
+
+
+
+{\displaystyle {\frac {\sqrt {x+2}}{x^{2}-3}}}
+
+.
+
+The terminology used to describe algebraic fractions is similar to that used for ordinary fractions. For example, an algebraic fraction is in lowest terms if the only factors common to the numerator and the denominator are 1 and −1. An algebraic fraction whose numerator or denominator, or both, contain a fraction, such as 
+
+
+
+
+
+
+1
++
+
+
+
+1
+x
+
+
+
+
+
+1
+−
+
+
+
+1
+x
+
+
+
+
+
+
+
+
+{\displaystyle {\frac {1+{\tfrac {1}{x}}}{1-{\tfrac {1}{x}}}}}
+
+, is called a complex fraction.
+
+The field of rational numbers is the field of fractions of the integers, while the integers themselves are not a field but rather an integral domain. Similarly, the rational fractions with coefficients in a field form the field of fractions of polynomials with coefficient in that field. Considering the rational fractions with real coefficients, radical expressions representing numbers, such as 
+
+
+
+
+
+
+2
+
+
+
+/
+
+2
+,
+
+
+
+{\displaystyle \textstyle {\sqrt {2}}/2,}
+
+ are also rational fractions, as are a transcendental numbers such as 
+
+
+
+π
+
+/
+
+2
+,
+
+
+{\textstyle \pi /2,}
+
+ since all of 
+
+
+
+
+
+2
+
+
+,
+π
+,
+
+
+{\displaystyle {\sqrt {2}},\pi ,}
+
+ and 
+
+
+
+2
+
+
+{\displaystyle 2}
+
+ are real numbers, and thus considered as coefficients. These same numbers, however, are not rational fractions with integer coefficients.
+
+The term partial fraction is used when decomposing rational fractions into sums of simpler fractions. For example, the rational fraction 
+
+
+
+
+
+
+2
+x
+
+
+
+x
+
+2
+
+
+−
+1
+
+
+
+
+
+{\displaystyle {\frac {2x}{x^{2}-1}}}
+
+ can be decomposed as the sum of two fractions: 
+
+
+
+
+
+1
+
+x
++
+1
+
+
+
++
+
+
+1
+
+x
+−
+1
+
+
+
+.
+
+
+{\displaystyle {\frac {1}{x+1}}+{\frac {1}{x-1}}.}
+
+ This is useful for the computation of antiderivatives of rational functions.
+
+A fraction may also contain radicals in the numerator and/or the denominator. If the denominator contains radicals, it can be helpful to rationalize it (compare Simplified form of a radical expression), especially if further operations, such as adding or comparing that fraction to another, are to be carried out. It is also more convenient if division is to be done manually. When the denominator is a monomial square root, it can be rationalized by multiplying both the top and the bottom of the fraction by the denominator:
+
+The process of rationalization of binomial denominators involves multiplying the top and the bottom of a fraction by the conjugate of the denominator so that the denominator becomes a rational number. For example:
+
+Even if this process results in the numerator being irrational, like in the examples above, the process may still facilitate subsequent manipulations by reducing the number of irrationals one has to work with in the denominator.
+
+In computer displays and typography, simple fractions are sometimes printed as a single character, e.g. ½ (one half). See the article on Number Forms for information on doing this in Unicode.
+
+Scientific publishing distinguishes four ways to set fractions, together with guidelines on use:[19]
+
+The earliest fractions were reciprocals of integers: ancient symbols representing one part of two, one part of three, one part of four, and so on.[22] The Egyptians used Egyptian fractions c. 1000 BC. About 4000 years ago, Egyptians divided with fractions using slightly different methods. They used least common multiples with unit fractions. Their methods gave the same answer as modern methods.[23] The Egyptians also had a different notation for dyadic fractions in the Akhmim Wooden Tablet and several Rhind Mathematical Papyrus problems.
+
+The Greeks used unit fractions and (later) continued fractions. Followers of the Greek philosopher Pythagoras (c. 530 BC) discovered that the square root of two cannot be expressed as a fraction of integers. (This is commonly though probably erroneously ascribed to Hippasus of Metapontum, who is said to have been executed for revealing this fact.) In 150 BC Jain mathematicians in India wrote the "Sthananga Sutra", which contains work on the theory of numbers, arithmetical operations, and operations with fractions.
+
+A modern expression of fractions known as bhinnarasi seems to have originated in India in the work of Aryabhatta (c. AD 500),[citation needed] Brahmagupta (c. 628), and Bhaskara (c. 1150).[24] Their works form fractions by placing the numerators (Sanskrit: amsa) over the denominators (cheda), but without a bar between them.[24] In Sanskrit literature, fractions were always expressed as an addition to or subtraction from an integer.[citation needed] The integer was written on one line and the fraction in its two parts on the next line. If the fraction was marked by a small circle ⟨०⟩ or cross ⟨+⟩, it is subtracted from the integer; if no such sign appears, it is understood to be added. For example, Bhaskara I writes[25]
+
+which is the equivalent of
+
+and would be written in modern notation as 61/4, 11/5, and 2 − 1/9 (i.e., 18/9).
+
+The horizontal fraction bar is first attested in the work of Al-Hassār (fl. 1200),[24] a Muslim mathematician from Fez, Morocco, who specialized in Islamic inheritance jurisprudence. In his discussion he writes, "... for example, if you are told to write three-fifths and a third of a fifth, write thus, 
+
+
+
+
+
+
+3
+
+1
+
+
+5
+
+3
+
+
+
+
+
+{\displaystyle {\frac {3\quad 1}{5\quad 3}}}
+
+."[26] The same fractional notation—with the fraction given before the integer[24]—appears soon after in the work of Leonardo Fibonacci in the 13th century.[27]
+
+In discussing the origins of decimal fractions, Dirk Jan Struik states:[28]
+
+"The introduction of decimal fractions as a common computational practice can be dated back to the Flemish pamphlet De Thiende, published at Leyden in 1585, together with a French translation, La Disme, by the Flemish mathematician Simon Stevin (1548–1620), then settled in the Northern Netherlands. It is true that decimal fractions were used by the Chinese many centuries before Stevin and that the Persian astronomer Al-Kāshī used both decimal and sexagesimal fractions with great ease in his Key to arithmetic (Samarkand, early fifteenth century)."[29]
+
+While the Persian mathematician Jamshīd al-Kāshī claimed to have discovered decimal fractions himself in the 15th century, J. Lennart Berggren notes that he was mistaken, as decimal fractions were first used five centuries before him by the Baghdadi mathematician Abu'l-Hasan al-Uqlidisi as early as the 10th century.[30][n 2]
+
+In primary schools, fractions have been demonstrated through Cuisenaire rods, Fraction Bars, fraction strips, fraction circles, paper (for folding or cutting), pattern blocks, pie-shaped pieces, plastic rectangles, grid paper, dot paper, geoboards, counters and computer software.
+
+Several states in the United States have adopted learning trajectories from the Common Core State Standards Initiative's guidelines for mathematics education. Aside from sequencing the learning of fractions and operations with fractions, the document provides the following definition of a fraction: "A number expressible in the form ​
+
+
+
+a
+
+
+{\displaystyle a}
+
+⁄
+
+
+
+b
+
+
+{\displaystyle b}
+
+ where 
+
+
+
+a
+
+
+{\displaystyle a}
+
+ is a whole number and 
+
+
+
+b
+
+
+{\displaystyle b}
+
+ is a positive whole number. (The word fraction in these standards always refers to a non-negative number.)"[32] The document itself also refers to negative fractions.

en/2056.html.txt

@@ -0,0 +1,2477 @@
+A fraction (from Latin fractus, "broken") represents a part of a whole or, more generally, any number of equal parts. When spoken in everyday English, a fraction describes how many parts of a certain size there are, for example, one-half, eight-fifths, three-quarters. A common, vulgar, or simple fraction (examples: 
+
+
+
+
+
+
+1
+2
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}}
+
+ and 
+
+
+
+
+
+
+17
+3
+
+
+
+
+
+{\displaystyle {\tfrac {17}{3}}}
+
+) consists of a numerator displayed above a line (or before a slash), and a non-zero denominator, displayed below (or after) that line. Numerators and denominators are also used in fractions that are not common, including compound fractions, complex fractions, and mixed numerals.
+
+In positive common fractions, the numerator and denominator are natural numbers. The numerator represents a number of equal parts, and the denominator indicates how many of those parts make up a unit or a whole. The denominator cannot be zero because zero parts can never make up a whole. For example, in the fraction 3⁄4, the numerator, 3, tells us that the fraction represents 3 equal parts, and the denominator, 4, tells us that 4 parts make up a whole. The picture to the right illustrates 
+
+
+
+
+
+
+3
+4
+
+
+
+
+
+{\displaystyle {\tfrac {3}{4}}}
+
+or ​3⁄4 of a cake.
+
+A common fraction is a numeral which represents a rational number. That same number can also be represented as a decimal, a percent, or with a negative exponent. For example, 0.01, 1%, and 10−2 all equal the fraction 1/100. An integer such as the number 7 can be thought of as having an implicit denominator of one: 7 equals 7/1.
+
+Other uses for fractions are to represent ratios and division.[1] Thus the fraction 3/4 is also used to represent the ratio 3:4 (the ratio of the part to the whole) and the division 3 ÷ 4 (three divided by four). The non-zero denominator in the case using a fraction to represent division is an example of the rule that division by zero is undefined.
+
+We can also write negative fractions, which represent the opposite of a positive fraction. For example, if 1/2 represents a half dollar profit, then −1/2 represents a half dollar loss. Because of the rules of division of signed numbers, which require that, for example, negative divided by positive is negative, −1/2, –1/2 and 1/–2, all represent the same fraction, negative one-half. Because a negative divided by a negative produces a positive, –1/–2 represents positive one-half.
+
+In mathematics the set of all numbers that can be expressed in the form a/b, where a and b are integers and b is not zero, is called the set of rational numbers and is represented by the symbol Q, which stands for quotient. The test for a number being a rational number is that it can be written in that form (i.e., as a common fraction). However, the word fraction is also used to describe mathematical expressions that are not rational numbers, for example algebraic fractions (quotients of algebraic expressions), and expressions that contain irrational numbers, such as √2/2 (see square root of 2) and π/4 (see proof that π is irrational).
+
+In a fraction, the number of equal parts being described is the numerator (from Latin numerātor, "counter" or "numberer"), and the type or variety of the parts is the denominator (from Latin dēnōminātor, "thing that names or designates").[2] As an example, the fraction ​8⁄5 amounts to eight parts, each of which is of the type named "fifth". In terms of division, the numerator corresponds to the dividend, and the denominator corresponds to the divisor.
+
+Informally, the numerator and denominator may be distinguished by placement alone but in formal contexts they are usually separated by a fraction bar. The fraction bar may be horizontal (as in 1/3), oblique (as in 2/5), or diagonal (as in ​4⁄9).[3] These marks are respectively known as the horizontal bar; the virgule, slash (US), or stroke (UK); and the fraction bar, solidus, or fraction slash.[n 1] In typography, fractions stacked vertically are also known as "en" or "nut fractions", and diagonal ones as "em" or "mutton fractions", based on whether a fraction with a single-digit numerator and denominator occupies the proportion of a narrow en square, or a wider em square.[3] In traditional typefounding, a piece of type bearing a complete fraction (e.g. 1/2) was known as a "case fraction," while those representing only part of fraction were called "piece fractions."
+
+The denominators of English fractions are generally expressed as ordinal numbers, in the plural if the numerator is not one. (For example, ​2⁄5 and ​3⁄5 are both read as a number of "fifths".) Exceptions include the denominator 2, which is always read "half" or "halves", the denominator 4, which may be alternatively expressed as "quarter"/"quarters" or as "fourth"/"fourths", and the denominator 100, which may be alternatively expressed as "hundredth"/"hundredths" or "percent". When the denominator is 1, it may be expressed in terms of "wholes" but is more commonly ignored, with the numerator read out as a whole number. (For example, 3/1 may be described as "three wholes" or as simply "three".) When the numerator is one, it may be omitted. (For example, "a tenth" or "each quarter".)
+
+The entire fraction may be expressed as a single composition, in which case it is hyphenated, or as a number of fractions with a numerator of one, in which case they are not. (For example, "two-fifths" is the fraction 2/5 and "two fifths" is the same fraction understood as 2 instances of ​1⁄5.) Fractions should always be hyphenated when used as adjectives. Alternatively, a fraction may be described by reading it out as the numerator "over" the denominator, with the denominator expressed as a cardinal number. (For example, 3/1 may also be expressed as "three over one".) The term "over" is used even in the case of solidus fractions, where the numbers are placed left and right of a slash mark. (For example, 1/2 may be read "one-half", "one half", or "one over two".) Fractions with large denominators that are not powers of ten are often rendered in this fashion (e.g., 1/117 as "one over one hundred seventeen") while those with denominators divisible by ten are typically read in the normal ordinal fashion (e.g., 6/1000000 as "six-millionths", "six millionths", or "six one-millionths").
+
+A simple fraction (also known as a common fraction or vulgar fraction) is a rational number written as a/b or 
+
+
+
+
+
+
+a
+b
+
+
+
+
+
+{\displaystyle {\tfrac {a}{b}}}
+
+, where a and b are both integers.[7] As with other fractions, the denominator (b) cannot be zero. Examples include 
+
+
+
+
+
+
+1
+2
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}}
+
+, 
+
+
+
+−
+
+
+
+8
+5
+
+
+
+
+
+{\displaystyle -{\tfrac {8}{5}}}
+
+, 
+
+
+
+
+
+
+
+−
+8
+
+5
+
+
+
+
+
+{\displaystyle {\tfrac {-8}{5}}}
+
+, and 
+
+
+
+
+
+
+8
+
+−
+5
+
+
+
+
+
+
+{\displaystyle {\tfrac {8}{-5}}}
+
+. Simple fractions can be positive or negative, and they can be proper or improper (see below). Compound fractions, complex fractions, mixed numerals, and decimals (see below) are not simple fractions; though, unless irrational, they can be evaluated to a simple fraction.
+
+Common fractions can be classified as either proper or improper. When the numerator and the denominator are both positive, the fraction is called proper if the numerator is less than the denominator, and improper otherwise.[8][9] In general, a common fraction is said to be a proper fraction if the absolute value of the fraction is strictly less than one—that is, if the fraction is greater than −1 and less than 1.[10][11] It is said to be an improper fraction, or sometimes top-heavy fraction,[12] if the absolute value of the fraction is greater than or equal to 1. Examples of proper fractions are 2/3, –3/4, and 4/9; examples of improper fractions are 9/4, –4/3, and 3/3.
+
+The reciprocal of a fraction is another fraction with the numerator and denominator exchanged. The reciprocal of 
+
+
+
+
+
+
+3
+7
+
+
+
+
+
+{\displaystyle {\tfrac {3}{7}}}
+
+, for instance, is 
+
+
+
+
+
+
+7
+3
+
+
+
+
+
+{\displaystyle {\tfrac {7}{3}}}
+
+. The product of a fraction and its reciprocal is 1, hence the reciprocal is the multiplicative inverse of a fraction. The reciprocal of a proper fraction is improper, and the reciprocal of an improper fraction not equal to 1 (that is, numerator and denominator are not equal) is a proper fraction.
+
+When the numerator and denominator of a fraction are equal (
+
+
+
+
+
+
+7
+7
+
+
+
+
+
+{\displaystyle {\tfrac {7}{7}}}
+
+, for example), its value is 1, and the fraction therefore is improper. Its reciprocal also has the value 1, and is improper, too.
+
+Any integer can be written as a fraction with the number one as denominator. For example, 17 can be written as 
+
+
+
+
+
+
+17
+1
+
+
+
+
+
+{\displaystyle {\tfrac {17}{1}}}
+
+, where 1 is sometimes referred to as the invisible denominator. Therefore, every fraction or integer, except for zero, has a reciprocal. The reciprocal of 17 is 
+
+
+
+
+
+
+1
+17
+
+
+
+
+
+{\displaystyle {\tfrac {1}{17}}}
+
+.
+
+A ratio is a relationship between two or more numbers that can be sometimes expressed as a fraction. Typically, a number of items are grouped and compared in a ratio, specifying numerically the relationship between each group. Ratios are expressed as "group 1 to group 2 ... to group n". For example, if a car lot had 12 vehicles, of which
+
+then the ratio of red to white to yellow cars is 6 to 2 to 4. The ratio of yellow cars to white cars is 4 to 2 and may be expressed as 4:2 or 2:1.
+
+A ratio is often converted to a fraction when it is expressed as a ratio to the whole. In the above example, the ratio of yellow cars to all the cars on the lot is 4:12 or 1:3. We can convert these ratios to a fraction and say that 4/12 of the cars or ⅓ of the cars in the lot are yellow. Therefore, if a person randomly chose one car on the lot, then there is a one in three chance or probability that it would be yellow.
+
+A decimal fraction is a fraction whose denominator is not given explicitly, but is understood to be an integer power of ten. Decimal fractions are commonly expressed using decimal notation in which the implied denominator is determined by the number of digits to the right of a decimal separator, the appearance of which (e.g., a period, a raised period (•), a comma) depends on the locale (for examples, see decimal separator). Thus for 0.75 the numerator is 75 and the implied denominator is 10 to the second power, viz. 100, because there are two digits to the right of the decimal separator. In decimal numbers greater than 1 (such as 3.75), the fractional part of the number is expressed by the digits to the right of the decimal (with a value of 0.75 in this case). 3.75 can be written either as an improper fraction, 375/100, or as a mixed number, 
+
+
+
+3
+
+
+
+75
+100
+
+
+
+
+
+{\displaystyle 3{\tfrac {75}{100}}}
+
+.
+
+Decimal fractions can also be expressed using scientific notation with negative exponents, such as 6.023×10−7, which represents 0.0000006023. The 10−7 represents a denominator of 107. Dividing by 107 moves the decimal point 7 places to the left.
+
+Decimal fractions with infinitely many digits to the right of the decimal separator represent an infinite series. For example, 1/3 = 0.333... represents the infinite series 3/10 + 3/100 + 3/1000 + ... .
+
+Another kind of fraction is the percentage (Latin per centum meaning "per hundred", represented by the symbol %), in which the implied denominator is always 100. Thus, 51% means 51/100. Percentages greater than 100 or less than zero are treated in the same way, e.g. 311% equals 311/100, and −27% equals −27/100.
+
+The related concept of permille or parts per thousand (ppt) has an implied denominator of 1000, while the more general parts-per notation, as in 75 parts per million (ppm), means that the proportion is 75/1,000,000.
+
+Whether common fractions or decimal fractions are used is often a matter of taste and context. Common fractions are used most often when the denominator is relatively small. By mental calculation, it is easier to multiply 16 by 3/16 than to do the same calculation using the fraction's decimal equivalent (0.1875). And it is more accurate to multiply 15 by 1/3, for example, than it is to multiply 15 by any decimal approximation of one third. Monetary values are commonly expressed as decimal fractions with denominator 100, i.e., with two decimals, for example $3.75. However, as noted above, in pre-decimal British currency, shillings and pence were often given the form (but not the meaning) of a fraction, as, for example 3/6 (read "three and six") meaning 3 shillings and 6 pence, and having no relationship to the fraction 3/6.
+
+A mixed numeral (also called a mixed fraction or mixed number) is a traditional denotation of the sum of a non-zero integer and a proper fraction (having the same sign). It is used primarily in measurement: 
+
+
+
+2
+
+
+
+3
+16
+
+
+
+
+
+{\displaystyle 2{\tfrac {3}{16}}}
+
+inches, for example. Scientific measurements almost invariably use decimal notation rather than mixed numbers. The sum is implied without the use of a visible operator such as the appropriate "+". For example, in referring to two entire cakes and three quarters of another cake, the numerals denoting the integer part and the fractional part of the cakes are written next to each other as 
+
+
+
+2
+
+
+
+3
+4
+
+
+
+
+
+{\displaystyle 2{\tfrac {3}{4}}}
+
+instead of the unambiguous notation 
+
+
+
+2
++
+
+
+
+3
+4
+
+
+
+.
+
+
+{\displaystyle 2+{\tfrac {3}{4}}.}
+
+ Negative mixed numerals, as in 
+
+
+
+−
+2
+
+
+
+3
+4
+
+
+
+
+
+{\displaystyle -2{\tfrac {3}{4}}}
+
+, are treated like 
+
+
+
+−
+(
+2
++
+
+
+
+3
+4
+
+
+
+)
+.
+
+
+{\displaystyle -(2+{\tfrac {3}{4}}).}
+
+ Any such sum of a whole plus a part can be converted to an improper fraction by applying the rules of adding unlike quantities.
+
+This tradition is, formally, in conflict with the notation in algebra where adjacent factors, without an explicit infix operator, denote a product. When two algebraic expressions are written next to each other, the operation of multiplication is implied by this general rule: 
+
+
+
+2
+x
+
+
+{\displaystyle 2x}
+
+ always means the product of 
+
+
+
+2
+
+
+{\displaystyle 2}
+
+ and 
+
+
+
+x
+
+
+{\textstyle x}
+
+, even if the value of 
+
+
+
+x
+
+
+{\displaystyle x}
+
+ is a fraction. The expression 
+
+
+
+2
+
+
+
+b
+c
+
+
+
+
+
+{\displaystyle 2{\tfrac {b}{c}}}
+
+ for example is not a mixed number; instead, multiplication is expressly required, where 
+
+
+
+2
+
+
+
+b
+c
+
+
+
+=
+2
+⋅
+
+
+
+b
+c
+
+
+
+.
+
+
+{\displaystyle 2{\tfrac {b}{c}}=2\cdot {\tfrac {b}{c}}.}
+
+For better readability, the multiplication is sometimes made explicit or parentheses are added. So, 
+
+
+
+2
+
+
+
+b
+c
+
+
+
+
+
+{\displaystyle 2{\tfrac {b}{c}}}
+
+ may be written as
+
+An improper fraction can be converted to a mixed number as follows:
+
+An Egyptian fraction is the sum of distinct positive unit fractions, for example 
+
+
+
+
+
+
+1
+2
+
+
+
++
+
+
+
+1
+3
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}+{\tfrac {1}{3}}}
+
+. This definition derives from the fact that the ancient Egyptians expressed all fractions except 
+
+
+
+
+
+
+1
+2
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}}
+
+, 
+
+
+
+
+
+
+2
+3
+
+
+
+
+
+{\displaystyle {\tfrac {2}{3}}}
+
+ and 
+
+
+
+
+
+
+3
+4
+
+
+
+
+
+{\displaystyle {\tfrac {3}{4}}}
+
+ in this manner. Every positive rational number can be expanded as an Egyptian fraction. For example, 
+
+
+
+
+
+
+5
+7
+
+
+
+
+
+{\displaystyle {\tfrac {5}{7}}}
+
+ can be written as 
+
+
+
+
+
+
+1
+2
+
+
+
++
+
+
+
+1
+6
+
+
+
++
+
+
+
+1
+21
+
+
+
+.
+
+
+{\displaystyle {\tfrac {1}{2}}+{\tfrac {1}{6}}+{\tfrac {1}{21}}.}
+
+ Any positive rational number can be written as a sum of unit fractions in infinitely many ways. Two ways to write 
+
+
+
+
+
+
+13
+17
+
+
+
+
+
+{\displaystyle {\tfrac {13}{17}}}
+
+ are 
+
+
+
+
+
+
+1
+2
+
+
+
++
+
+
+
+1
+4
+
+
+
++
+
+
+
+1
+68
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}+{\tfrac {1}{4}}+{\tfrac {1}{68}}}
+
+ and 
+
+
+
+
+
+
+1
+3
+
+
+
++
+
+
+
+1
+4
+
+
+
++
+
+
+
+1
+6
+
+
+
++
+
+
+
+1
+68
+
+
+
+
+
+{\displaystyle {\tfrac {1}{3}}+{\tfrac {1}{4}}+{\tfrac {1}{6}}+{\tfrac {1}{68}}}
+
+.
+
+The notions ‘complex fraction’ and ‘compound fraction’ are both outdated[13] and nowadays used in no well-defined manner, partly even taken synonymously for each other[14] or for mixed numerals.[15] They lost their meaning as technical terms and the attributes "complex" and "compound" tend to be used in their every day meaning of "consisting of parts".
+
+In a complex fraction, either the numerator, or the denominator, or both, is a fraction or a mixed number,[16][17] corresponding to division of fractions. For example, 
+
+
+
+
+
+
+
+1
+2
+
+
+
+
+1
+3
+
+
+
+
+
+
+{\displaystyle {\frac {\tfrac {1}{2}}{\tfrac {1}{3}}}}
+
+ and 
+
+
+
+
+
+
+12
+
+
+
+3
+4
+
+
+
+
+26
+
+
+
+
+{\displaystyle {\frac {12{\tfrac {3}{4}}}{26}}}
+
+ are complex fractions. To reduce a complex fraction to a simple fraction, treat the longest fraction line as representing division. For example:
+
+If, in a complex fraction, there is no unique way to tell which fraction lines takes precedence, then this expression is improperly formed, because of ambiguity. So 5/10/20/40 is not a valid mathematical expression, because of multiple possible interpretations, e.g. as
+
+A compound fraction is a fraction of a fraction, or any number of fractions connected with the word of,[16][17] corresponding to multiplication of fractions. To reduce a compound fraction to a simple fraction, just carry out the multiplication (see the section on multiplication). For example, 
+
+
+
+
+
+
+3
+4
+
+
+
+
+
+{\displaystyle {\tfrac {3}{4}}}
+
+ of 
+
+
+
+
+
+
+5
+7
+
+
+
+
+
+{\displaystyle {\tfrac {5}{7}}}
+
+ is a compound fraction, corresponding to 
+
+
+
+
+
+
+3
+4
+
+
+
+×
+
+
+
+5
+7
+
+
+
+=
+
+
+
+15
+28
+
+
+
+
+
+{\displaystyle {\tfrac {3}{4}}\times {\tfrac {5}{7}}={\tfrac {15}{28}}}
+
+. The terms compound fraction and complex fraction are closely related and sometimes one is used as a synonym for the other. (For example, the compound fraction 
+
+
+
+
+
+
+3
+4
+
+
+
+×
+
+
+
+5
+7
+
+
+
+
+
+{\displaystyle {\tfrac {3}{4}}\times {\tfrac {5}{7}}}
+
+ is equivalent to the complex fraction 
+
+
+
+
+
+
+
+3
+
+/
+
+4
+
+
+7
+
+/
+
+5
+
+
+
+
+
+
+{\displaystyle {\tfrac {3/4}{7/5}}}
+
+.)
+
+Like whole numbers, fractions obey the commutative, associative, and distributive laws, and the rule against division by zero.
+
+Multiplying the numerator and denominator of a fraction by the same (non-zero) number results in a fraction that is equivalent to the original fraction. This is true because for any non-zero number 
+
+
+
+n
+
+
+{\displaystyle n}
+
+, the fraction 
+
+
+
+
+
+
+n
+n
+
+
+
+=
+1
+
+
+{\displaystyle {\tfrac {n}{n}}=1}
+
+. Therefore, multiplying by 
+
+
+
+
+
+
+n
+n
+
+
+
+
+
+{\displaystyle {\tfrac {n}{n}}}
+
+is equivalent to multiplying by one, and any number multiplied by one has the same value as the original number. By way of an example, start with the fraction 
+
+
+
+
+
+
+1
+2
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}}
+
+. When the numerator and denominator are both multiplied by 2, the result is 
+
+
+
+
+
+
+2
+4
+
+
+
+
+
+{\displaystyle {\tfrac {2}{4}}}
+
+, which has the same value (0.5) as 
+
+
+
+
+
+
+1
+2
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}}
+
+. To picture this visually, imagine cutting a cake into four pieces; two of the pieces together (
+
+
+
+
+
+
+2
+4
+
+
+
+
+
+{\displaystyle {\tfrac {2}{4}}}
+
+) make up half the cake (
+
+
+
+
+
+
+1
+2
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}}
+
+).
+
+Dividing the numerator and denominator of a fraction by the same non-zero number will also yield an equivalent fraction. If the numerator and the denominator of a fraction are both divisible by a number (called a factor) greater than 1, then the fraction can be reduced to an equal fraction with a smaller numerator and a smaller denominator. To do this, the greatest common factor is identified, and both the numerator and the denominator are divided by this factor. For example, if both the numerator and the denominator of the fraction 
+
+
+
+
+
+
+a
+b
+
+
+
+
+
+{\displaystyle {\tfrac {a}{b}}}
+
+are divisible by 
+
+
+
+c
+,
+
+
+{\displaystyle c,}
+
+ then they can be written as 
+
+
+
+a
+=
+c
+d
+
+
+{\displaystyle a=cd}
+
+ and 
+
+
+
+b
+=
+c
+e
+,
+
+
+{\displaystyle b=ce,}
+
+ so the fraction becomes 
+
+
+
+
+
+
+
+c
+d
+
+
+c
+e
+
+
+
+
+
+
+{\displaystyle {\tfrac {cd}{ce}}}
+
+, which can be reduced by dividing both the numerator and denominator by 
+
+
+
+c
+
+
+{\displaystyle c}
+
+ to give the reduced fraction 
+
+
+
+
+
+
+d
+e
+
+
+
+.
+
+
+{\displaystyle {\tfrac {d}{e}}.}
+
+If the numerator and the denominator do not share any factor greater than 1, then the fraction is said to be irreducible, in lowest terms, or in simplest terms. For example, 
+
+
+
+
+
+
+3
+9
+
+
+
+
+
+{\displaystyle {\tfrac {3}{9}}}
+
+is not in lowest terms because both 3 and 9 can be exactly divided by 3. In contrast, 
+
+
+
+
+
+
+3
+8
+
+
+
+
+
+{\displaystyle {\tfrac {3}{8}}}
+
+ is in lowest terms—the only positive integer that goes into both 3 and 8 evenly is 1.
+
+Using these rules, we can show that 
+
+
+
+
+
+
+5
+10
+
+
+
+
+
+{\displaystyle {\tfrac {5}{10}}}
+
+= 
+
+
+
+
+
+
+1
+2
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}}
+
+= 
+
+
+
+
+
+
+10
+20
+
+
+
+
+
+{\displaystyle {\tfrac {10}{20}}}
+
+= 
+
+
+
+
+
+
+50
+100
+
+
+
+
+
+{\displaystyle {\tfrac {50}{100}}}
+
+.
+
+As another example, since the greatest common divisor of 63 and 462 is 21, the fraction 
+
+
+
+
+
+
+63
+462
+
+
+
+
+
+{\displaystyle {\tfrac {63}{462}}}
+
+can be reduced to lowest terms by dividing the numerator and denominator by 21:
+
+The Euclidean algorithm gives a method for finding the greatest common divisor of any two positive integers.
+
+Comparing fractions with the same positive denominator yields the same result as comparing the numerators:
+
+If the equal denominators are negative, then the opposite result of comparing the numerators holds for the fractions:
+
+If two positive fractions have the same numerator, then the fraction with the smaller denominator is the larger number. When a whole is divided into equal pieces, if fewer equal pieces are needed to make up the whole, then each piece must be larger. When two positive fractions have the same numerator, they represent the same number of parts, but in the fraction with the smaller denominator, the parts are larger.
+
+One way to compare fractions with different numerators and denominators is to find a common denominator. To compare 
+
+
+
+
+
+
+a
+b
+
+
+
+
+
+{\displaystyle {\tfrac {a}{b}}}
+
+ and 
+
+
+
+
+
+
+c
+d
+
+
+
+
+
+{\displaystyle {\tfrac {c}{d}}}
+
+, these are converted to 
+
+
+
+
+
+
+
+a
+⋅
+d
+
+
+b
+⋅
+d
+
+
+
+
+
+
+{\displaystyle {\tfrac {a\cdot d}{b\cdot d}}}
+
+ and 
+
+
+
+
+
+
+
+b
+⋅
+c
+
+
+b
+⋅
+d
+
+
+
+
+
+
+{\displaystyle {\tfrac {b\cdot c}{b\cdot d}}}
+
+ (where the dot signifies multiplication and is an alternative symbol to ×). Then bd is a common denominator and the numerators ad and bc can be compared. It is not necessary to determine the value of the common denominator to compare fractions – one can just compare ad and bc, without evaluating bd, e.g., comparing 
+
+
+
+
+
+
+2
+3
+
+
+
+
+
+{\displaystyle {\tfrac {2}{3}}}
+
+ ? 
+
+
+
+
+
+
+1
+2
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}}
+
+ gives 
+
+
+
+
+
+
+4
+6
+
+
+
+>
+
+
+
+3
+6
+
+
+
+
+
+{\displaystyle {\tfrac {4}{6}}>{\tfrac {3}{6}}}
+
+.
+
+For the more laborious question 
+
+
+
+
+
+
+5
+18
+
+
+
+
+
+{\displaystyle {\tfrac {5}{18}}}
+
+ ? 
+
+
+
+
+
+
+4
+17
+
+
+
+,
+
+
+{\displaystyle {\tfrac {4}{17}},}
+
+ multiply top and bottom of each fraction by the denominator of the other fraction, to get a common denominator, yielding 
+
+
+
+
+
+
+
+5
+×
+17
+
+
+18
+×
+17
+
+
+
+
+
+
+{\displaystyle {\tfrac {5\times 17}{18\times 17}}}
+
+ ? 
+
+
+
+
+
+
+
+18
+×
+4
+
+
+18
+×
+17
+
+
+
+
+
+
+{\displaystyle {\tfrac {18\times 4}{18\times 17}}}
+
+. It is not necessary to calculate 
+
+
+
+18
+×
+17
+
+
+{\displaystyle 18\times 17}
+
+ – only the numerators need to be compared. Since 5×17 (= 85) is greater than 4×18 (= 72), the result of comparing is 
+
+
+
+
+
+
+5
+18
+
+
+
+>
+
+
+
+4
+17
+
+
+
+
+
+{\displaystyle {\tfrac {5}{18}}>{\tfrac {4}{17}}}
+
+.
+
+Because every negative number, including negative fractions, is less than zero, and every positive number, including positive fractions, is greater than zero, it follows that any negative fraction is less than any positive fraction. This allows, together with the above rules, to compare all possible fractions.
+
+The first rule of addition is that only like quantities can be added; for example, various quantities of quarters. Unlike quantities, such as adding thirds to quarters, must first be converted to like quantities as described below: Imagine a pocket containing two quarters, and another pocket containing three quarters; in total, there are five quarters. Since four quarters is equivalent to one (dollar), this can be represented as follows:
+
+To add fractions containing unlike quantities (e.g. quarters and thirds), it is necessary to convert all amounts to like quantities. It is easy to work out the chosen type of fraction to convert to; simply multiply together the two denominators (bottom number) of each fraction. In case of an integer number apply the invisible denominator 
+
+
+
+1.
+
+
+{\displaystyle 1.}
+
+For adding quarters to thirds, both types of fraction are converted to twelfths, thus:
+
+Consider adding the following two quantities:
+
+First, convert 
+
+
+
+
+
+
+3
+5
+
+
+
+
+
+{\displaystyle {\tfrac {3}{5}}}
+
+ into fifteenths by multiplying both the numerator and denominator by three: 
+
+
+
+
+
+
+3
+5
+
+
+
+×
+
+
+
+3
+3
+
+
+
+=
+
+
+
+9
+15
+
+
+
+
+
+{\displaystyle {\tfrac {3}{5}}\times {\tfrac {3}{3}}={\tfrac {9}{15}}}
+
+. Since 
+
+
+
+
+
+
+3
+3
+
+
+
+
+
+{\displaystyle {\tfrac {3}{3}}}
+
+ equals 1, multiplication by 
+
+
+
+
+
+
+3
+3
+
+
+
+
+
+{\displaystyle {\tfrac {3}{3}}}
+
+ does not change the value of the fraction.
+
+Second, convert 
+
+
+
+
+
+
+2
+3
+
+
+
+
+
+{\displaystyle {\tfrac {2}{3}}}
+
+ into fifteenths by multiplying both the numerator and denominator by five: 
+
+
+
+
+
+
+2
+3
+
+
+
+×
+
+
+
+5
+5
+
+
+
+=
+
+
+
+10
+15
+
+
+
+
+
+{\displaystyle {\tfrac {2}{3}}\times {\tfrac {5}{5}}={\tfrac {10}{15}}}
+
+.
+
+Now it can be seen that:
+
+is equivalent to:
+
+This method can be expressed algebraically:
+
+This algebraic method always works, thereby guaranteeing that the sum of simple fractions is always again a simple fraction. However, if the single denominators contain a common factor, a smaller denominator than the product of these can be used. For example, when adding 
+
+
+
+
+
+
+3
+4
+
+
+
+
+
+{\displaystyle {\tfrac {3}{4}}}
+
+ and 
+
+
+
+
+
+
+5
+6
+
+
+
+
+
+{\displaystyle {\tfrac {5}{6}}}
+
+ the single denominators have a common factor 
+
+
+
+2
+,
+
+
+{\displaystyle 2,}
+
+ and therefore, instead of the denominator 24 (4 × 6), the halved denominator 12 may be used, not only reducing the denominator in the result, but also the factors in the numerator.
+
+The smallest possible denominator is given by the least common multiple of the single denominators, which results from dividing the rote multiple by all common factors of the single denominators. This is called the least common denominator.
+
+The process for subtracting fractions is, in essence, the same as that of adding them: find a common denominator, and change each fraction to an equivalent fraction with the chosen common denominator. The resulting fraction will have that denominator, and its numerator will be the result of subtracting the numerators of the original fractions. For instance,
+
+To multiply fractions, multiply the numerators and multiply the denominators. Thus:
+
+To explain the process, consider one third of one quarter. Using the example of a cake, if three small slices of equal size make up a quarter, and four quarters make up a whole, twelve of these small, equal slices make up a whole. Therefore, a third of a quarter is a twelfth. Now consider the numerators. The first fraction, two thirds, is twice as large as one third. Since one third of a quarter is one twelfth, two thirds of a quarter is two twelfth. The second fraction, three quarters, is three times as large as one quarter, so two thirds of three quarters is three times as large as two thirds of one quarter. Thus two thirds times three quarters is six twelfths.
+
+A short cut for multiplying fractions is called "cancellation". Effectively the answer is reduced to lowest terms during multiplication. For example:
+
+A two is a common factor in both the numerator of the left fraction and the denominator of the right and is divided out of both. Three is a common factor of the left denominator and right numerator and is divided out of both.
+
+Since a whole number can be rewritten as itself divided by 1, normal fraction multiplication rules can still apply.
+
+This method works because the fraction 6/1 means six equal parts, each one of which is a whole.
+
+When multiplying mixed numbers, it is considered preferable[citation needed] to convert the mixed number into an improper fraction. For example:
+
+In other words, 
+
+
+
+2
+
+
+
+3
+4
+
+
+
+
+
+{\displaystyle 2{\tfrac {3}{4}}}
+
+ is the same as 
+
+
+
+
+
+
+8
+4
+
+
+
++
+
+
+
+3
+4
+
+
+
+
+
+{\displaystyle {\tfrac {8}{4}}+{\tfrac {3}{4}}}
+
+, making 11 quarters in total (because 2 cakes, each split into quarters makes 8 quarters total) and 33 quarters is 
+
+
+
+8
+
+
+
+1
+4
+
+
+
+
+
+{\displaystyle 8{\tfrac {1}{4}}}
+
+, since 8 cakes, each made of quarters, is 32 quarters in total.
+
+To divide a fraction by a whole number, you may either divide the numerator by the number, if it goes evenly into the numerator, or multiply the denominator by the number. For example, 
+
+
+
+
+
+
+10
+3
+
+
+
+÷
+5
+
+
+{\displaystyle {\tfrac {10}{3}}\div 5}
+
+ equals 
+
+
+
+
+
+
+2
+3
+
+
+
+
+
+{\displaystyle {\tfrac {2}{3}}}
+
+ and also equals 
+
+
+
+
+
+
+10
+
+3
+⋅
+5
+
+
+
+
+=
+
+
+
+10
+15
+
+
+
+
+
+{\displaystyle {\tfrac {10}{3\cdot 5}}={\tfrac {10}{15}}}
+
+, which reduces to 
+
+
+
+
+
+
+2
+3
+
+
+
+
+
+{\displaystyle {\tfrac {2}{3}}}
+
+. To divide a number by a fraction, multiply that number by the reciprocal of that fraction. Thus, 
+
+
+
+
+
+
+1
+2
+
+
+
+÷
+
+
+
+3
+4
+
+
+
+=
+
+
+
+1
+2
+
+
+
+×
+
+
+
+4
+3
+
+
+
+=
+
+
+
+
+1
+⋅
+4
+
+
+2
+⋅
+3
+
+
+
+
+=
+
+
+
+2
+3
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}\div {\tfrac {3}{4}}={\tfrac {1}{2}}\times {\tfrac {4}{3}}={\tfrac {1\cdot 4}{2\cdot 3}}={\tfrac {2}{3}}}
+
+.
+
+To change a common fraction to a decimal, do a long division of the decimal representations of the numerator by the denominator (this is idiomatically also phrased as "divide the denominator into the numerator"), and round the answer to the desired accuracy. For example, to change ¼ to a decimal, divide 
+
+
+
+1.00
+
+
+{\displaystyle 1.00}
+
+ by 
+
+
+
+4
+
+
+{\displaystyle 4}
+
+ ("
+
+
+
+4
+
+
+{\displaystyle 4}
+
+ into 
+
+
+
+1.00
+
+
+{\displaystyle 1.00}
+
+"), to obtain 
+
+
+
+0.25
+
+
+{\displaystyle 0.25}
+
+. To change ⅓ to a decimal, divide 
+
+
+
+1.000...
+
+
+{\displaystyle 1.000...}
+
+ by 
+
+
+
+3
+
+
+{\displaystyle 3}
+
+ ("
+
+
+
+3
+
+
+{\displaystyle 3}
+
+ into 
+
+
+
+1.0000...
+
+
+{\displaystyle 1.0000...}
+
+"), and stop when the desired accuracy is obtained, e.g., at 
+
+
+
+4
+
+
+{\displaystyle 4}
+
+ decimals with 
+
+
+
+0.3333
+
+
+{\displaystyle 0.3333}
+
+. The fraction ¼ can be written exactly with two decimal digits, while the fraction ⅓ cannot be written exactly as a decimal with a finite number of digits. To change a decimal to a fraction, write in the denominator a 
+
+
+
+1
+
+
+{\displaystyle 1}
+
+ followed by as many zeroes as there are digits to the right of the decimal point, and write in the numerator all the digits of the original decimal, just omitting the decimal point. Thus 
+
+
+
+12.3456
+=
+
+
+
+123456
+10000
+
+
+
+.
+
+
+{\displaystyle 12.3456={\tfrac {123456}{10000}}.}
+
+Decimal numbers, while arguably more useful to work with when performing calculations, sometimes lack the precision that common fractions have. Sometimes an infinite repeating decimal is required to reach the same precision. Thus, it is often useful to convert repeating decimals into fractions.
+
+The preferred[by whom?] way to indicate a repeating decimal is to place a bar (known as a vinculum) over the digits that repeat, for example 0.789 = 0.789789789... For repeating patterns where the repeating pattern begins immediately after the decimal point, a simple division of the pattern by the same number of nines as numbers it has will suffice. For example:
+
+In case leading zeros precede the pattern, the nines are suffixed by the same number of trailing zeros:
+
+In case a non-repeating set of decimals precede the pattern (such as 0.1523987), we can write it as the sum of the non-repeating and repeating parts, respectively:
+
+Then, convert both parts to fractions, and add them using the methods described above:
+
+Alternatively, algebra can be used, such as below:
+
+In addition to being of great practical importance, fractions are also studied by mathematicians, who check that the rules for fractions given above are consistent and reliable. Mathematicians define a fraction as an ordered pair 
+
+
+
+(
+a
+,
+b
+)
+
+
+{\displaystyle (a,b)}
+
+of integers 
+
+
+
+a
+
+
+{\displaystyle a}
+
+and 
+
+
+
+b
+≠
+0
+,
+
+
+{\displaystyle b\neq 0,}
+
+ for which the operations addition, subtraction, multiplication, and division are defined as follows:[18]
+
+These definitions agree in every case with the definitions given above; only the notation is different. Alternatively, instead of defining subtraction and division as operations, the "inverse" fractions with respect to addition and multiplication might be defined as:
+
+Furthermore, the relation, specified as
+
+is an equivalence relation of fractions. Each fraction from one equivalence class may be considered as a representative for the whole class, and each whole class may be considered as one abstract fraction. This equivalence is preserved by the above defined operations, i.e., the results of operating on fractions are independent of the selection of representatives from their equivalence class. Formally, for addition of fractions
+
+and similarly for the other operations.
+
+In case of fractions of integers the fractions with 
+
+
+
+(
+a
+,
+b
+)
+
+
+{\displaystyle (a,b)}
+
+coprime are often taken as uniquely determined representatives for their equivalent fractions, which are considered to be the same rational number. This way the fractions of integers make up the field of the rational numbers.
+
+More generally, a and b may be elements of any integral domain R, in which case a fraction is an element of the field of fractions of R. For example, polynomials in one indeterminate, with coefficients from some integral domain D, are themselves an integral domain, call it P. So for a and b elements of P, the generated field of fractions is the field of rational fractions (also known as the field of rational functions).
+
+An algebraic fraction is the indicated quotient of two algebraic expressions. As with fractions of integers, the denominator of an algebraic fraction cannot be zero. Two examples of algebraic fractions are 
+
+
+
+
+
+
+3
+x
+
+
+
+x
+
+2
+
+
++
+2
+x
+−
+3
+
+
+
+
+
+{\displaystyle {\frac {3x}{x^{2}+2x-3}}}
+
+ and 
+
+
+
+
+
+
+x
++
+2
+
+
+
+x
+
+2
+
+
+−
+3
+
+
+
+
+
+{\displaystyle {\frac {\sqrt {x+2}}{x^{2}-3}}}
+
+. Algebraic fractions are subject to the same field properties as arithmetic fractions.
+
+If the numerator and the denominator are polynomials, as in 
+
+
+
+
+
+
+3
+x
+
+
+
+x
+
+2
+
+
++
+2
+x
+−
+3
+
+
+
+
+
+{\displaystyle {\frac {3x}{x^{2}+2x-3}}}
+
+, the algebraic fraction is called a rational fraction (or rational expression). An irrational fraction is one that is not rational, as, for example, one that contains the variable under a fractional exponent or root, as in 
+
+
+
+
+
+
+x
++
+2
+
+
+
+x
+
+2
+
+
+−
+3
+
+
+
+
+
+{\displaystyle {\frac {\sqrt {x+2}}{x^{2}-3}}}
+
+.
+
+The terminology used to describe algebraic fractions is similar to that used for ordinary fractions. For example, an algebraic fraction is in lowest terms if the only factors common to the numerator and the denominator are 1 and −1. An algebraic fraction whose numerator or denominator, or both, contain a fraction, such as 
+
+
+
+
+
+
+1
++
+
+
+
+1
+x
+
+
+
+
+
+1
+−
+
+
+
+1
+x
+
+
+
+
+
+
+
+
+{\displaystyle {\frac {1+{\tfrac {1}{x}}}{1-{\tfrac {1}{x}}}}}
+
+, is called a complex fraction.
+
+The field of rational numbers is the field of fractions of the integers, while the integers themselves are not a field but rather an integral domain. Similarly, the rational fractions with coefficients in a field form the field of fractions of polynomials with coefficient in that field. Considering the rational fractions with real coefficients, radical expressions representing numbers, such as 
+
+
+
+
+
+
+2
+
+
+
+/
+
+2
+,
+
+
+
+{\displaystyle \textstyle {\sqrt {2}}/2,}
+
+ are also rational fractions, as are a transcendental numbers such as 
+
+
+
+π
+
+/
+
+2
+,
+
+
+{\textstyle \pi /2,}
+
+ since all of 
+
+
+
+
+
+2
+
+
+,
+π
+,
+
+
+{\displaystyle {\sqrt {2}},\pi ,}
+
+ and 
+
+
+
+2
+
+
+{\displaystyle 2}
+
+ are real numbers, and thus considered as coefficients. These same numbers, however, are not rational fractions with integer coefficients.
+
+The term partial fraction is used when decomposing rational fractions into sums of simpler fractions. For example, the rational fraction 
+
+
+
+
+
+
+2
+x
+
+
+
+x
+
+2
+
+
+−
+1
+
+
+
+
+
+{\displaystyle {\frac {2x}{x^{2}-1}}}
+
+ can be decomposed as the sum of two fractions: 
+
+
+
+
+
+1
+
+x
++
+1
+
+
+
++
+
+
+1
+
+x
+−
+1
+
+
+
+.
+
+
+{\displaystyle {\frac {1}{x+1}}+{\frac {1}{x-1}}.}
+
+ This is useful for the computation of antiderivatives of rational functions.
+
+A fraction may also contain radicals in the numerator and/or the denominator. If the denominator contains radicals, it can be helpful to rationalize it (compare Simplified form of a radical expression), especially if further operations, such as adding or comparing that fraction to another, are to be carried out. It is also more convenient if division is to be done manually. When the denominator is a monomial square root, it can be rationalized by multiplying both the top and the bottom of the fraction by the denominator:
+
+The process of rationalization of binomial denominators involves multiplying the top and the bottom of a fraction by the conjugate of the denominator so that the denominator becomes a rational number. For example:
+
+Even if this process results in the numerator being irrational, like in the examples above, the process may still facilitate subsequent manipulations by reducing the number of irrationals one has to work with in the denominator.
+
+In computer displays and typography, simple fractions are sometimes printed as a single character, e.g. ½ (one half). See the article on Number Forms for information on doing this in Unicode.
+
+Scientific publishing distinguishes four ways to set fractions, together with guidelines on use:[19]
+
+The earliest fractions were reciprocals of integers: ancient symbols representing one part of two, one part of three, one part of four, and so on.[22] The Egyptians used Egyptian fractions c. 1000 BC. About 4000 years ago, Egyptians divided with fractions using slightly different methods. They used least common multiples with unit fractions. Their methods gave the same answer as modern methods.[23] The Egyptians also had a different notation for dyadic fractions in the Akhmim Wooden Tablet and several Rhind Mathematical Papyrus problems.
+
+The Greeks used unit fractions and (later) continued fractions. Followers of the Greek philosopher Pythagoras (c. 530 BC) discovered that the square root of two cannot be expressed as a fraction of integers. (This is commonly though probably erroneously ascribed to Hippasus of Metapontum, who is said to have been executed for revealing this fact.) In 150 BC Jain mathematicians in India wrote the "Sthananga Sutra", which contains work on the theory of numbers, arithmetical operations, and operations with fractions.
+
+A modern expression of fractions known as bhinnarasi seems to have originated in India in the work of Aryabhatta (c. AD 500),[citation needed] Brahmagupta (c. 628), and Bhaskara (c. 1150).[24] Their works form fractions by placing the numerators (Sanskrit: amsa) over the denominators (cheda), but without a bar between them.[24] In Sanskrit literature, fractions were always expressed as an addition to or subtraction from an integer.[citation needed] The integer was written on one line and the fraction in its two parts on the next line. If the fraction was marked by a small circle ⟨०⟩ or cross ⟨+⟩, it is subtracted from the integer; if no such sign appears, it is understood to be added. For example, Bhaskara I writes[25]
+
+which is the equivalent of
+
+and would be written in modern notation as 61/4, 11/5, and 2 − 1/9 (i.e., 18/9).
+
+The horizontal fraction bar is first attested in the work of Al-Hassār (fl. 1200),[24] a Muslim mathematician from Fez, Morocco, who specialized in Islamic inheritance jurisprudence. In his discussion he writes, "... for example, if you are told to write three-fifths and a third of a fifth, write thus, 
+
+
+
+
+
+
+3
+
+1
+
+
+5
+
+3
+
+
+
+
+
+{\displaystyle {\frac {3\quad 1}{5\quad 3}}}
+
+."[26] The same fractional notation—with the fraction given before the integer[24]—appears soon after in the work of Leonardo Fibonacci in the 13th century.[27]
+
+In discussing the origins of decimal fractions, Dirk Jan Struik states:[28]
+
+"The introduction of decimal fractions as a common computational practice can be dated back to the Flemish pamphlet De Thiende, published at Leyden in 1585, together with a French translation, La Disme, by the Flemish mathematician Simon Stevin (1548–1620), then settled in the Northern Netherlands. It is true that decimal fractions were used by the Chinese many centuries before Stevin and that the Persian astronomer Al-Kāshī used both decimal and sexagesimal fractions with great ease in his Key to arithmetic (Samarkand, early fifteenth century)."[29]
+
+While the Persian mathematician Jamshīd al-Kāshī claimed to have discovered decimal fractions himself in the 15th century, J. Lennart Berggren notes that he was mistaken, as decimal fractions were first used five centuries before him by the Baghdadi mathematician Abu'l-Hasan al-Uqlidisi as early as the 10th century.[30][n 2]
+
+In primary schools, fractions have been demonstrated through Cuisenaire rods, Fraction Bars, fraction strips, fraction circles, paper (for folding or cutting), pattern blocks, pie-shaped pieces, plastic rectangles, grid paper, dot paper, geoboards, counters and computer software.
+
+Several states in the United States have adopted learning trajectories from the Common Core State Standards Initiative's guidelines for mathematics education. Aside from sequencing the learning of fractions and operations with fractions, the document provides the following definition of a fraction: "A number expressible in the form ​
+
+
+
+a
+
+
+{\displaystyle a}
+
+⁄
+
+
+
+b
+
+
+{\displaystyle b}
+
+ where 
+
+
+
+a
+
+
+{\displaystyle a}
+
+ is a whole number and 
+
+
+
+b
+
+
+{\displaystyle b}
+
+ is a positive whole number. (The word fraction in these standards always refers to a non-negative number.)"[32] The document itself also refers to negative fractions.

en/2057.html.txt

@@ -0,0 +1,2477 @@
+A fraction (from Latin fractus, "broken") represents a part of a whole or, more generally, any number of equal parts. When spoken in everyday English, a fraction describes how many parts of a certain size there are, for example, one-half, eight-fifths, three-quarters. A common, vulgar, or simple fraction (examples: 
+
+
+
+
+
+
+1
+2
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}}
+
+ and 
+
+
+
+
+
+
+17
+3
+
+
+
+
+
+{\displaystyle {\tfrac {17}{3}}}
+
+) consists of a numerator displayed above a line (or before a slash), and a non-zero denominator, displayed below (or after) that line. Numerators and denominators are also used in fractions that are not common, including compound fractions, complex fractions, and mixed numerals.
+
+In positive common fractions, the numerator and denominator are natural numbers. The numerator represents a number of equal parts, and the denominator indicates how many of those parts make up a unit or a whole. The denominator cannot be zero because zero parts can never make up a whole. For example, in the fraction 3⁄4, the numerator, 3, tells us that the fraction represents 3 equal parts, and the denominator, 4, tells us that 4 parts make up a whole. The picture to the right illustrates 
+
+
+
+
+
+
+3
+4
+
+
+
+
+
+{\displaystyle {\tfrac {3}{4}}}
+
+or ​3⁄4 of a cake.
+
+A common fraction is a numeral which represents a rational number. That same number can also be represented as a decimal, a percent, or with a negative exponent. For example, 0.01, 1%, and 10−2 all equal the fraction 1/100. An integer such as the number 7 can be thought of as having an implicit denominator of one: 7 equals 7/1.
+
+Other uses for fractions are to represent ratios and division.[1] Thus the fraction 3/4 is also used to represent the ratio 3:4 (the ratio of the part to the whole) and the division 3 ÷ 4 (three divided by four). The non-zero denominator in the case using a fraction to represent division is an example of the rule that division by zero is undefined.
+
+We can also write negative fractions, which represent the opposite of a positive fraction. For example, if 1/2 represents a half dollar profit, then −1/2 represents a half dollar loss. Because of the rules of division of signed numbers, which require that, for example, negative divided by positive is negative, −1/2, –1/2 and 1/–2, all represent the same fraction, negative one-half. Because a negative divided by a negative produces a positive, –1/–2 represents positive one-half.
+
+In mathematics the set of all numbers that can be expressed in the form a/b, where a and b are integers and b is not zero, is called the set of rational numbers and is represented by the symbol Q, which stands for quotient. The test for a number being a rational number is that it can be written in that form (i.e., as a common fraction). However, the word fraction is also used to describe mathematical expressions that are not rational numbers, for example algebraic fractions (quotients of algebraic expressions), and expressions that contain irrational numbers, such as √2/2 (see square root of 2) and π/4 (see proof that π is irrational).
+
+In a fraction, the number of equal parts being described is the numerator (from Latin numerātor, "counter" or "numberer"), and the type or variety of the parts is the denominator (from Latin dēnōminātor, "thing that names or designates").[2] As an example, the fraction ​8⁄5 amounts to eight parts, each of which is of the type named "fifth". In terms of division, the numerator corresponds to the dividend, and the denominator corresponds to the divisor.
+
+Informally, the numerator and denominator may be distinguished by placement alone but in formal contexts they are usually separated by a fraction bar. The fraction bar may be horizontal (as in 1/3), oblique (as in 2/5), or diagonal (as in ​4⁄9).[3] These marks are respectively known as the horizontal bar; the virgule, slash (US), or stroke (UK); and the fraction bar, solidus, or fraction slash.[n 1] In typography, fractions stacked vertically are also known as "en" or "nut fractions", and diagonal ones as "em" or "mutton fractions", based on whether a fraction with a single-digit numerator and denominator occupies the proportion of a narrow en square, or a wider em square.[3] In traditional typefounding, a piece of type bearing a complete fraction (e.g. 1/2) was known as a "case fraction," while those representing only part of fraction were called "piece fractions."
+
+The denominators of English fractions are generally expressed as ordinal numbers, in the plural if the numerator is not one. (For example, ​2⁄5 and ​3⁄5 are both read as a number of "fifths".) Exceptions include the denominator 2, which is always read "half" or "halves", the denominator 4, which may be alternatively expressed as "quarter"/"quarters" or as "fourth"/"fourths", and the denominator 100, which may be alternatively expressed as "hundredth"/"hundredths" or "percent". When the denominator is 1, it may be expressed in terms of "wholes" but is more commonly ignored, with the numerator read out as a whole number. (For example, 3/1 may be described as "three wholes" or as simply "three".) When the numerator is one, it may be omitted. (For example, "a tenth" or "each quarter".)
+
+The entire fraction may be expressed as a single composition, in which case it is hyphenated, or as a number of fractions with a numerator of one, in which case they are not. (For example, "two-fifths" is the fraction 2/5 and "two fifths" is the same fraction understood as 2 instances of ​1⁄5.) Fractions should always be hyphenated when used as adjectives. Alternatively, a fraction may be described by reading it out as the numerator "over" the denominator, with the denominator expressed as a cardinal number. (For example, 3/1 may also be expressed as "three over one".) The term "over" is used even in the case of solidus fractions, where the numbers are placed left and right of a slash mark. (For example, 1/2 may be read "one-half", "one half", or "one over two".) Fractions with large denominators that are not powers of ten are often rendered in this fashion (e.g., 1/117 as "one over one hundred seventeen") while those with denominators divisible by ten are typically read in the normal ordinal fashion (e.g., 6/1000000 as "six-millionths", "six millionths", or "six one-millionths").
+
+A simple fraction (also known as a common fraction or vulgar fraction) is a rational number written as a/b or 
+
+
+
+
+
+
+a
+b
+
+
+
+
+
+{\displaystyle {\tfrac {a}{b}}}
+
+, where a and b are both integers.[7] As with other fractions, the denominator (b) cannot be zero. Examples include 
+
+
+
+
+
+
+1
+2
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}}
+
+, 
+
+
+
+−
+
+
+
+8
+5
+
+
+
+
+
+{\displaystyle -{\tfrac {8}{5}}}
+
+, 
+
+
+
+
+
+
+
+−
+8
+
+5
+
+
+
+
+
+{\displaystyle {\tfrac {-8}{5}}}
+
+, and 
+
+
+
+
+
+
+8
+
+−
+5
+
+
+
+
+
+
+{\displaystyle {\tfrac {8}{-5}}}
+
+. Simple fractions can be positive or negative, and they can be proper or improper (see below). Compound fractions, complex fractions, mixed numerals, and decimals (see below) are not simple fractions; though, unless irrational, they can be evaluated to a simple fraction.
+
+Common fractions can be classified as either proper or improper. When the numerator and the denominator are both positive, the fraction is called proper if the numerator is less than the denominator, and improper otherwise.[8][9] In general, a common fraction is said to be a proper fraction if the absolute value of the fraction is strictly less than one—that is, if the fraction is greater than −1 and less than 1.[10][11] It is said to be an improper fraction, or sometimes top-heavy fraction,[12] if the absolute value of the fraction is greater than or equal to 1. Examples of proper fractions are 2/3, –3/4, and 4/9; examples of improper fractions are 9/4, –4/3, and 3/3.
+
+The reciprocal of a fraction is another fraction with the numerator and denominator exchanged. The reciprocal of 
+
+
+
+
+
+
+3
+7
+
+
+
+
+
+{\displaystyle {\tfrac {3}{7}}}
+
+, for instance, is 
+
+
+
+
+
+
+7
+3
+
+
+
+
+
+{\displaystyle {\tfrac {7}{3}}}
+
+. The product of a fraction and its reciprocal is 1, hence the reciprocal is the multiplicative inverse of a fraction. The reciprocal of a proper fraction is improper, and the reciprocal of an improper fraction not equal to 1 (that is, numerator and denominator are not equal) is a proper fraction.
+
+When the numerator and denominator of a fraction are equal (
+
+
+
+
+
+
+7
+7
+
+
+
+
+
+{\displaystyle {\tfrac {7}{7}}}
+
+, for example), its value is 1, and the fraction therefore is improper. Its reciprocal also has the value 1, and is improper, too.
+
+Any integer can be written as a fraction with the number one as denominator. For example, 17 can be written as 
+
+
+
+
+
+
+17
+1
+
+
+
+
+
+{\displaystyle {\tfrac {17}{1}}}
+
+, where 1 is sometimes referred to as the invisible denominator. Therefore, every fraction or integer, except for zero, has a reciprocal. The reciprocal of 17 is 
+
+
+
+
+
+
+1
+17
+
+
+
+
+
+{\displaystyle {\tfrac {1}{17}}}
+
+.
+
+A ratio is a relationship between two or more numbers that can be sometimes expressed as a fraction. Typically, a number of items are grouped and compared in a ratio, specifying numerically the relationship between each group. Ratios are expressed as "group 1 to group 2 ... to group n". For example, if a car lot had 12 vehicles, of which
+
+then the ratio of red to white to yellow cars is 6 to 2 to 4. The ratio of yellow cars to white cars is 4 to 2 and may be expressed as 4:2 or 2:1.
+
+A ratio is often converted to a fraction when it is expressed as a ratio to the whole. In the above example, the ratio of yellow cars to all the cars on the lot is 4:12 or 1:3. We can convert these ratios to a fraction and say that 4/12 of the cars or ⅓ of the cars in the lot are yellow. Therefore, if a person randomly chose one car on the lot, then there is a one in three chance or probability that it would be yellow.
+
+A decimal fraction is a fraction whose denominator is not given explicitly, but is understood to be an integer power of ten. Decimal fractions are commonly expressed using decimal notation in which the implied denominator is determined by the number of digits to the right of a decimal separator, the appearance of which (e.g., a period, a raised period (•), a comma) depends on the locale (for examples, see decimal separator). Thus for 0.75 the numerator is 75 and the implied denominator is 10 to the second power, viz. 100, because there are two digits to the right of the decimal separator. In decimal numbers greater than 1 (such as 3.75), the fractional part of the number is expressed by the digits to the right of the decimal (with a value of 0.75 in this case). 3.75 can be written either as an improper fraction, 375/100, or as a mixed number, 
+
+
+
+3
+
+
+
+75
+100
+
+
+
+
+
+{\displaystyle 3{\tfrac {75}{100}}}
+
+.
+
+Decimal fractions can also be expressed using scientific notation with negative exponents, such as 6.023×10−7, which represents 0.0000006023. The 10−7 represents a denominator of 107. Dividing by 107 moves the decimal point 7 places to the left.
+
+Decimal fractions with infinitely many digits to the right of the decimal separator represent an infinite series. For example, 1/3 = 0.333... represents the infinite series 3/10 + 3/100 + 3/1000 + ... .
+
+Another kind of fraction is the percentage (Latin per centum meaning "per hundred", represented by the symbol %), in which the implied denominator is always 100. Thus, 51% means 51/100. Percentages greater than 100 or less than zero are treated in the same way, e.g. 311% equals 311/100, and −27% equals −27/100.
+
+The related concept of permille or parts per thousand (ppt) has an implied denominator of 1000, while the more general parts-per notation, as in 75 parts per million (ppm), means that the proportion is 75/1,000,000.
+
+Whether common fractions or decimal fractions are used is often a matter of taste and context. Common fractions are used most often when the denominator is relatively small. By mental calculation, it is easier to multiply 16 by 3/16 than to do the same calculation using the fraction's decimal equivalent (0.1875). And it is more accurate to multiply 15 by 1/3, for example, than it is to multiply 15 by any decimal approximation of one third. Monetary values are commonly expressed as decimal fractions with denominator 100, i.e., with two decimals, for example $3.75. However, as noted above, in pre-decimal British currency, shillings and pence were often given the form (but not the meaning) of a fraction, as, for example 3/6 (read "three and six") meaning 3 shillings and 6 pence, and having no relationship to the fraction 3/6.
+
+A mixed numeral (also called a mixed fraction or mixed number) is a traditional denotation of the sum of a non-zero integer and a proper fraction (having the same sign). It is used primarily in measurement: 
+
+
+
+2
+
+
+
+3
+16
+
+
+
+
+
+{\displaystyle 2{\tfrac {3}{16}}}
+
+inches, for example. Scientific measurements almost invariably use decimal notation rather than mixed numbers. The sum is implied without the use of a visible operator such as the appropriate "+". For example, in referring to two entire cakes and three quarters of another cake, the numerals denoting the integer part and the fractional part of the cakes are written next to each other as 
+
+
+
+2
+
+
+
+3
+4
+
+
+
+
+
+{\displaystyle 2{\tfrac {3}{4}}}
+
+instead of the unambiguous notation 
+
+
+
+2
++
+
+
+
+3
+4
+
+
+
+.
+
+
+{\displaystyle 2+{\tfrac {3}{4}}.}
+
+ Negative mixed numerals, as in 
+
+
+
+−
+2
+
+
+
+3
+4
+
+
+
+
+
+{\displaystyle -2{\tfrac {3}{4}}}
+
+, are treated like 
+
+
+
+−
+(
+2
++
+
+
+
+3
+4
+
+
+
+)
+.
+
+
+{\displaystyle -(2+{\tfrac {3}{4}}).}
+
+ Any such sum of a whole plus a part can be converted to an improper fraction by applying the rules of adding unlike quantities.
+
+This tradition is, formally, in conflict with the notation in algebra where adjacent factors, without an explicit infix operator, denote a product. When two algebraic expressions are written next to each other, the operation of multiplication is implied by this general rule: 
+
+
+
+2
+x
+
+
+{\displaystyle 2x}
+
+ always means the product of 
+
+
+
+2
+
+
+{\displaystyle 2}
+
+ and 
+
+
+
+x
+
+
+{\textstyle x}
+
+, even if the value of 
+
+
+
+x
+
+
+{\displaystyle x}
+
+ is a fraction. The expression 
+
+
+
+2
+
+
+
+b
+c
+
+
+
+
+
+{\displaystyle 2{\tfrac {b}{c}}}
+
+ for example is not a mixed number; instead, multiplication is expressly required, where 
+
+
+
+2
+
+
+
+b
+c
+
+
+
+=
+2
+⋅
+
+
+
+b
+c
+
+
+
+.
+
+
+{\displaystyle 2{\tfrac {b}{c}}=2\cdot {\tfrac {b}{c}}.}
+
+For better readability, the multiplication is sometimes made explicit or parentheses are added. So, 
+
+
+
+2
+
+
+
+b
+c
+
+
+
+
+
+{\displaystyle 2{\tfrac {b}{c}}}
+
+ may be written as
+
+An improper fraction can be converted to a mixed number as follows:
+
+An Egyptian fraction is the sum of distinct positive unit fractions, for example 
+
+
+
+
+
+
+1
+2
+
+
+
++
+
+
+
+1
+3
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}+{\tfrac {1}{3}}}
+
+. This definition derives from the fact that the ancient Egyptians expressed all fractions except 
+
+
+
+
+
+
+1
+2
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}}
+
+, 
+
+
+
+
+
+
+2
+3
+
+
+
+
+
+{\displaystyle {\tfrac {2}{3}}}
+
+ and 
+
+
+
+
+
+
+3
+4
+
+
+
+
+
+{\displaystyle {\tfrac {3}{4}}}
+
+ in this manner. Every positive rational number can be expanded as an Egyptian fraction. For example, 
+
+
+
+
+
+
+5
+7
+
+
+
+
+
+{\displaystyle {\tfrac {5}{7}}}
+
+ can be written as 
+
+
+
+
+
+
+1
+2
+
+
+
++
+
+
+
+1
+6
+
+
+
++
+
+
+
+1
+21
+
+
+
+.
+
+
+{\displaystyle {\tfrac {1}{2}}+{\tfrac {1}{6}}+{\tfrac {1}{21}}.}
+
+ Any positive rational number can be written as a sum of unit fractions in infinitely many ways. Two ways to write 
+
+
+
+
+
+
+13
+17
+
+
+
+
+
+{\displaystyle {\tfrac {13}{17}}}
+
+ are 
+
+
+
+
+
+
+1
+2
+
+
+
++
+
+
+
+1
+4
+
+
+
++
+
+
+
+1
+68
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}+{\tfrac {1}{4}}+{\tfrac {1}{68}}}
+
+ and 
+
+
+
+
+
+
+1
+3
+
+
+
++
+
+
+
+1
+4
+
+
+
++
+
+
+
+1
+6
+
+
+
++
+
+
+
+1
+68
+
+
+
+
+
+{\displaystyle {\tfrac {1}{3}}+{\tfrac {1}{4}}+{\tfrac {1}{6}}+{\tfrac {1}{68}}}
+
+.
+
+The notions ‘complex fraction’ and ‘compound fraction’ are both outdated[13] and nowadays used in no well-defined manner, partly even taken synonymously for each other[14] or for mixed numerals.[15] They lost their meaning as technical terms and the attributes "complex" and "compound" tend to be used in their every day meaning of "consisting of parts".
+
+In a complex fraction, either the numerator, or the denominator, or both, is a fraction or a mixed number,[16][17] corresponding to division of fractions. For example, 
+
+
+
+
+
+
+
+1
+2
+
+
+
+
+1
+3
+
+
+
+
+
+
+{\displaystyle {\frac {\tfrac {1}{2}}{\tfrac {1}{3}}}}
+
+ and 
+
+
+
+
+
+
+12
+
+
+
+3
+4
+
+
+
+
+26
+
+
+
+
+{\displaystyle {\frac {12{\tfrac {3}{4}}}{26}}}
+
+ are complex fractions. To reduce a complex fraction to a simple fraction, treat the longest fraction line as representing division. For example:
+
+If, in a complex fraction, there is no unique way to tell which fraction lines takes precedence, then this expression is improperly formed, because of ambiguity. So 5/10/20/40 is not a valid mathematical expression, because of multiple possible interpretations, e.g. as
+
+A compound fraction is a fraction of a fraction, or any number of fractions connected with the word of,[16][17] corresponding to multiplication of fractions. To reduce a compound fraction to a simple fraction, just carry out the multiplication (see the section on multiplication). For example, 
+
+
+
+
+
+
+3
+4
+
+
+
+
+
+{\displaystyle {\tfrac {3}{4}}}
+
+ of 
+
+
+
+
+
+
+5
+7
+
+
+
+
+
+{\displaystyle {\tfrac {5}{7}}}
+
+ is a compound fraction, corresponding to 
+
+
+
+
+
+
+3
+4
+
+
+
+×
+
+
+
+5
+7
+
+
+
+=
+
+
+
+15
+28
+
+
+
+
+
+{\displaystyle {\tfrac {3}{4}}\times {\tfrac {5}{7}}={\tfrac {15}{28}}}
+
+. The terms compound fraction and complex fraction are closely related and sometimes one is used as a synonym for the other. (For example, the compound fraction 
+
+
+
+
+
+
+3
+4
+
+
+
+×
+
+
+
+5
+7
+
+
+
+
+
+{\displaystyle {\tfrac {3}{4}}\times {\tfrac {5}{7}}}
+
+ is equivalent to the complex fraction 
+
+
+
+
+
+
+
+3
+
+/
+
+4
+
+
+7
+
+/
+
+5
+
+
+
+
+
+
+{\displaystyle {\tfrac {3/4}{7/5}}}
+
+.)
+
+Like whole numbers, fractions obey the commutative, associative, and distributive laws, and the rule against division by zero.
+
+Multiplying the numerator and denominator of a fraction by the same (non-zero) number results in a fraction that is equivalent to the original fraction. This is true because for any non-zero number 
+
+
+
+n
+
+
+{\displaystyle n}
+
+, the fraction 
+
+
+
+
+
+
+n
+n
+
+
+
+=
+1
+
+
+{\displaystyle {\tfrac {n}{n}}=1}
+
+. Therefore, multiplying by 
+
+
+
+
+
+
+n
+n
+
+
+
+
+
+{\displaystyle {\tfrac {n}{n}}}
+
+is equivalent to multiplying by one, and any number multiplied by one has the same value as the original number. By way of an example, start with the fraction 
+
+
+
+
+
+
+1
+2
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}}
+
+. When the numerator and denominator are both multiplied by 2, the result is 
+
+
+
+
+
+
+2
+4
+
+
+
+
+
+{\displaystyle {\tfrac {2}{4}}}
+
+, which has the same value (0.5) as 
+
+
+
+
+
+
+1
+2
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}}
+
+. To picture this visually, imagine cutting a cake into four pieces; two of the pieces together (
+
+
+
+
+
+
+2
+4
+
+
+
+
+
+{\displaystyle {\tfrac {2}{4}}}
+
+) make up half the cake (
+
+
+
+
+
+
+1
+2
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}}
+
+).
+
+Dividing the numerator and denominator of a fraction by the same non-zero number will also yield an equivalent fraction. If the numerator and the denominator of a fraction are both divisible by a number (called a factor) greater than 1, then the fraction can be reduced to an equal fraction with a smaller numerator and a smaller denominator. To do this, the greatest common factor is identified, and both the numerator and the denominator are divided by this factor. For example, if both the numerator and the denominator of the fraction 
+
+
+
+
+
+
+a
+b
+
+
+
+
+
+{\displaystyle {\tfrac {a}{b}}}
+
+are divisible by 
+
+
+
+c
+,
+
+
+{\displaystyle c,}
+
+ then they can be written as 
+
+
+
+a
+=
+c
+d
+
+
+{\displaystyle a=cd}
+
+ and 
+
+
+
+b
+=
+c
+e
+,
+
+
+{\displaystyle b=ce,}
+
+ so the fraction becomes 
+
+
+
+
+
+
+
+c
+d
+
+
+c
+e
+
+
+
+
+
+
+{\displaystyle {\tfrac {cd}{ce}}}
+
+, which can be reduced by dividing both the numerator and denominator by 
+
+
+
+c
+
+
+{\displaystyle c}
+
+ to give the reduced fraction 
+
+
+
+
+
+
+d
+e
+
+
+
+.
+
+
+{\displaystyle {\tfrac {d}{e}}.}
+
+If the numerator and the denominator do not share any factor greater than 1, then the fraction is said to be irreducible, in lowest terms, or in simplest terms. For example, 
+
+
+
+
+
+
+3
+9
+
+
+
+
+
+{\displaystyle {\tfrac {3}{9}}}
+
+is not in lowest terms because both 3 and 9 can be exactly divided by 3. In contrast, 
+
+
+
+
+
+
+3
+8
+
+
+
+
+
+{\displaystyle {\tfrac {3}{8}}}
+
+ is in lowest terms—the only positive integer that goes into both 3 and 8 evenly is 1.
+
+Using these rules, we can show that 
+
+
+
+
+
+
+5
+10
+
+
+
+
+
+{\displaystyle {\tfrac {5}{10}}}
+
+= 
+
+
+
+
+
+
+1
+2
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}}
+
+= 
+
+
+
+
+
+
+10
+20
+
+
+
+
+
+{\displaystyle {\tfrac {10}{20}}}
+
+= 
+
+
+
+
+
+
+50
+100
+
+
+
+
+
+{\displaystyle {\tfrac {50}{100}}}
+
+.
+
+As another example, since the greatest common divisor of 63 and 462 is 21, the fraction 
+
+
+
+
+
+
+63
+462
+
+
+
+
+
+{\displaystyle {\tfrac {63}{462}}}
+
+can be reduced to lowest terms by dividing the numerator and denominator by 21:
+
+The Euclidean algorithm gives a method for finding the greatest common divisor of any two positive integers.
+
+Comparing fractions with the same positive denominator yields the same result as comparing the numerators:
+
+If the equal denominators are negative, then the opposite result of comparing the numerators holds for the fractions:
+
+If two positive fractions have the same numerator, then the fraction with the smaller denominator is the larger number. When a whole is divided into equal pieces, if fewer equal pieces are needed to make up the whole, then each piece must be larger. When two positive fractions have the same numerator, they represent the same number of parts, but in the fraction with the smaller denominator, the parts are larger.
+
+One way to compare fractions with different numerators and denominators is to find a common denominator. To compare 
+
+
+
+
+
+
+a
+b
+
+
+
+
+
+{\displaystyle {\tfrac {a}{b}}}
+
+ and 
+
+
+
+
+
+
+c
+d
+
+
+
+
+
+{\displaystyle {\tfrac {c}{d}}}
+
+, these are converted to 
+
+
+
+
+
+
+
+a
+⋅
+d
+
+
+b
+⋅
+d
+
+
+
+
+
+
+{\displaystyle {\tfrac {a\cdot d}{b\cdot d}}}
+
+ and 
+
+
+
+
+
+
+
+b
+⋅
+c
+
+
+b
+⋅
+d
+
+
+
+
+
+
+{\displaystyle {\tfrac {b\cdot c}{b\cdot d}}}
+
+ (where the dot signifies multiplication and is an alternative symbol to ×). Then bd is a common denominator and the numerators ad and bc can be compared. It is not necessary to determine the value of the common denominator to compare fractions – one can just compare ad and bc, without evaluating bd, e.g., comparing 
+
+
+
+
+
+
+2
+3
+
+
+
+
+
+{\displaystyle {\tfrac {2}{3}}}
+
+ ? 
+
+
+
+
+
+
+1
+2
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}}
+
+ gives 
+
+
+
+
+
+
+4
+6
+
+
+
+>
+
+
+
+3
+6
+
+
+
+
+
+{\displaystyle {\tfrac {4}{6}}>{\tfrac {3}{6}}}
+
+.
+
+For the more laborious question 
+
+
+
+
+
+
+5
+18
+
+
+
+
+
+{\displaystyle {\tfrac {5}{18}}}
+
+ ? 
+
+
+
+
+
+
+4
+17
+
+
+
+,
+
+
+{\displaystyle {\tfrac {4}{17}},}
+
+ multiply top and bottom of each fraction by the denominator of the other fraction, to get a common denominator, yielding 
+
+
+
+
+
+
+
+5
+×
+17
+
+
+18
+×
+17
+
+
+
+
+
+
+{\displaystyle {\tfrac {5\times 17}{18\times 17}}}
+
+ ? 
+
+
+
+
+
+
+
+18
+×
+4
+
+
+18
+×
+17
+
+
+
+
+
+
+{\displaystyle {\tfrac {18\times 4}{18\times 17}}}
+
+. It is not necessary to calculate 
+
+
+
+18
+×
+17
+
+
+{\displaystyle 18\times 17}
+
+ – only the numerators need to be compared. Since 5×17 (= 85) is greater than 4×18 (= 72), the result of comparing is 
+
+
+
+
+
+
+5
+18
+
+
+
+>
+
+
+
+4
+17
+
+
+
+
+
+{\displaystyle {\tfrac {5}{18}}>{\tfrac {4}{17}}}
+
+.
+
+Because every negative number, including negative fractions, is less than zero, and every positive number, including positive fractions, is greater than zero, it follows that any negative fraction is less than any positive fraction. This allows, together with the above rules, to compare all possible fractions.
+
+The first rule of addition is that only like quantities can be added; for example, various quantities of quarters. Unlike quantities, such as adding thirds to quarters, must first be converted to like quantities as described below: Imagine a pocket containing two quarters, and another pocket containing three quarters; in total, there are five quarters. Since four quarters is equivalent to one (dollar), this can be represented as follows:
+
+To add fractions containing unlike quantities (e.g. quarters and thirds), it is necessary to convert all amounts to like quantities. It is easy to work out the chosen type of fraction to convert to; simply multiply together the two denominators (bottom number) of each fraction. In case of an integer number apply the invisible denominator 
+
+
+
+1.
+
+
+{\displaystyle 1.}
+
+For adding quarters to thirds, both types of fraction are converted to twelfths, thus:
+
+Consider adding the following two quantities:
+
+First, convert 
+
+
+
+
+
+
+3
+5
+
+
+
+
+
+{\displaystyle {\tfrac {3}{5}}}
+
+ into fifteenths by multiplying both the numerator and denominator by three: 
+
+
+
+
+
+
+3
+5
+
+
+
+×
+
+
+
+3
+3
+
+
+
+=
+
+
+
+9
+15
+
+
+
+
+
+{\displaystyle {\tfrac {3}{5}}\times {\tfrac {3}{3}}={\tfrac {9}{15}}}
+
+. Since 
+
+
+
+
+
+
+3
+3
+
+
+
+
+
+{\displaystyle {\tfrac {3}{3}}}
+
+ equals 1, multiplication by 
+
+
+
+
+
+
+3
+3
+
+
+
+
+
+{\displaystyle {\tfrac {3}{3}}}
+
+ does not change the value of the fraction.
+
+Second, convert 
+
+
+
+
+
+
+2
+3
+
+
+
+
+
+{\displaystyle {\tfrac {2}{3}}}
+
+ into fifteenths by multiplying both the numerator and denominator by five: 
+
+
+
+
+
+
+2
+3
+
+
+
+×
+
+
+
+5
+5
+
+
+
+=
+
+
+
+10
+15
+
+
+
+
+
+{\displaystyle {\tfrac {2}{3}}\times {\tfrac {5}{5}}={\tfrac {10}{15}}}
+
+.
+
+Now it can be seen that:
+
+is equivalent to:
+
+This method can be expressed algebraically:
+
+This algebraic method always works, thereby guaranteeing that the sum of simple fractions is always again a simple fraction. However, if the single denominators contain a common factor, a smaller denominator than the product of these can be used. For example, when adding 
+
+
+
+
+
+
+3
+4
+
+
+
+
+
+{\displaystyle {\tfrac {3}{4}}}
+
+ and 
+
+
+
+
+
+
+5
+6
+
+
+
+
+
+{\displaystyle {\tfrac {5}{6}}}
+
+ the single denominators have a common factor 
+
+
+
+2
+,
+
+
+{\displaystyle 2,}
+
+ and therefore, instead of the denominator 24 (4 × 6), the halved denominator 12 may be used, not only reducing the denominator in the result, but also the factors in the numerator.
+
+The smallest possible denominator is given by the least common multiple of the single denominators, which results from dividing the rote multiple by all common factors of the single denominators. This is called the least common denominator.
+
+The process for subtracting fractions is, in essence, the same as that of adding them: find a common denominator, and change each fraction to an equivalent fraction with the chosen common denominator. The resulting fraction will have that denominator, and its numerator will be the result of subtracting the numerators of the original fractions. For instance,
+
+To multiply fractions, multiply the numerators and multiply the denominators. Thus:
+
+To explain the process, consider one third of one quarter. Using the example of a cake, if three small slices of equal size make up a quarter, and four quarters make up a whole, twelve of these small, equal slices make up a whole. Therefore, a third of a quarter is a twelfth. Now consider the numerators. The first fraction, two thirds, is twice as large as one third. Since one third of a quarter is one twelfth, two thirds of a quarter is two twelfth. The second fraction, three quarters, is three times as large as one quarter, so two thirds of three quarters is three times as large as two thirds of one quarter. Thus two thirds times three quarters is six twelfths.
+
+A short cut for multiplying fractions is called "cancellation". Effectively the answer is reduced to lowest terms during multiplication. For example:
+
+A two is a common factor in both the numerator of the left fraction and the denominator of the right and is divided out of both. Three is a common factor of the left denominator and right numerator and is divided out of both.
+
+Since a whole number can be rewritten as itself divided by 1, normal fraction multiplication rules can still apply.
+
+This method works because the fraction 6/1 means six equal parts, each one of which is a whole.
+
+When multiplying mixed numbers, it is considered preferable[citation needed] to convert the mixed number into an improper fraction. For example:
+
+In other words, 
+
+
+
+2
+
+
+
+3
+4
+
+
+
+
+
+{\displaystyle 2{\tfrac {3}{4}}}
+
+ is the same as 
+
+
+
+
+
+
+8
+4
+
+
+
++
+
+
+
+3
+4
+
+
+
+
+
+{\displaystyle {\tfrac {8}{4}}+{\tfrac {3}{4}}}
+
+, making 11 quarters in total (because 2 cakes, each split into quarters makes 8 quarters total) and 33 quarters is 
+
+
+
+8
+
+
+
+1
+4
+
+
+
+
+
+{\displaystyle 8{\tfrac {1}{4}}}
+
+, since 8 cakes, each made of quarters, is 32 quarters in total.
+
+To divide a fraction by a whole number, you may either divide the numerator by the number, if it goes evenly into the numerator, or multiply the denominator by the number. For example, 
+
+
+
+
+
+
+10
+3
+
+
+
+÷
+5
+
+
+{\displaystyle {\tfrac {10}{3}}\div 5}
+
+ equals 
+
+
+
+
+
+
+2
+3
+
+
+
+
+
+{\displaystyle {\tfrac {2}{3}}}
+
+ and also equals 
+
+
+
+
+
+
+10
+
+3
+⋅
+5
+
+
+
+
+=
+
+
+
+10
+15
+
+
+
+
+
+{\displaystyle {\tfrac {10}{3\cdot 5}}={\tfrac {10}{15}}}
+
+, which reduces to 
+
+
+
+
+
+
+2
+3
+
+
+
+
+
+{\displaystyle {\tfrac {2}{3}}}
+
+. To divide a number by a fraction, multiply that number by the reciprocal of that fraction. Thus, 
+
+
+
+
+
+
+1
+2
+
+
+
+÷
+
+
+
+3
+4
+
+
+
+=
+
+
+
+1
+2
+
+
+
+×
+
+
+
+4
+3
+
+
+
+=
+
+
+
+
+1
+⋅
+4
+
+
+2
+⋅
+3
+
+
+
+
+=
+
+
+
+2
+3
+
+
+
+
+
+{\displaystyle {\tfrac {1}{2}}\div {\tfrac {3}{4}}={\tfrac {1}{2}}\times {\tfrac {4}{3}}={\tfrac {1\cdot 4}{2\cdot 3}}={\tfrac {2}{3}}}
+
+.
+
+To change a common fraction to a decimal, do a long division of the decimal representations of the numerator by the denominator (this is idiomatically also phrased as "divide the denominator into the numerator"), and round the answer to the desired accuracy. For example, to change ¼ to a decimal, divide 
+
+
+
+1.00
+
+
+{\displaystyle 1.00}
+
+ by 
+
+
+
+4
+
+
+{\displaystyle 4}
+
+ ("
+
+
+
+4
+
+
+{\displaystyle 4}
+
+ into 
+
+
+
+1.00
+
+
+{\displaystyle 1.00}
+
+"), to obtain 
+
+
+
+0.25
+
+
+{\displaystyle 0.25}
+
+. To change ⅓ to a decimal, divide 
+
+
+
+1.000...
+
+
+{\displaystyle 1.000...}
+
+ by 
+
+
+
+3
+
+
+{\displaystyle 3}
+
+ ("
+
+
+
+3
+
+
+{\displaystyle 3}
+
+ into 
+
+
+
+1.0000...
+
+
+{\displaystyle 1.0000...}
+
+"), and stop when the desired accuracy is obtained, e.g., at 
+
+
+
+4
+
+
+{\displaystyle 4}
+
+ decimals with 
+
+
+
+0.3333
+
+
+{\displaystyle 0.3333}
+
+. The fraction ¼ can be written exactly with two decimal digits, while the fraction ⅓ cannot be written exactly as a decimal with a finite number of digits. To change a decimal to a fraction, write in the denominator a 
+
+
+
+1
+
+
+{\displaystyle 1}
+
+ followed by as many zeroes as there are digits to the right of the decimal point, and write in the numerator all the digits of the original decimal, just omitting the decimal point. Thus 
+
+
+
+12.3456
+=
+
+
+
+123456
+10000
+
+
+
+.
+
+
+{\displaystyle 12.3456={\tfrac {123456}{10000}}.}
+
+Decimal numbers, while arguably more useful to work with when performing calculations, sometimes lack the precision that common fractions have. Sometimes an infinite repeating decimal is required to reach the same precision. Thus, it is often useful to convert repeating decimals into fractions.
+
+The preferred[by whom?] way to indicate a repeating decimal is to place a bar (known as a vinculum) over the digits that repeat, for example 0.789 = 0.789789789... For repeating patterns where the repeating pattern begins immediately after the decimal point, a simple division of the pattern by the same number of nines as numbers it has will suffice. For example:
+
+In case leading zeros precede the pattern, the nines are suffixed by the same number of trailing zeros:
+
+In case a non-repeating set of decimals precede the pattern (such as 0.1523987), we can write it as the sum of the non-repeating and repeating parts, respectively:
+
+Then, convert both parts to fractions, and add them using the methods described above:
+
+Alternatively, algebra can be used, such as below:
+
+In addition to being of great practical importance, fractions are also studied by mathematicians, who check that the rules for fractions given above are consistent and reliable. Mathematicians define a fraction as an ordered pair 
+
+
+
+(
+a
+,
+b
+)
+
+
+{\displaystyle (a,b)}
+
+of integers 
+
+
+
+a
+
+
+{\displaystyle a}
+
+and 
+
+
+
+b
+≠
+0
+,
+
+
+{\displaystyle b\neq 0,}
+
+ for which the operations addition, subtraction, multiplication, and division are defined as follows:[18]
+
+These definitions agree in every case with the definitions given above; only the notation is different. Alternatively, instead of defining subtraction and division as operations, the "inverse" fractions with respect to addition and multiplication might be defined as:
+
+Furthermore, the relation, specified as
+
+is an equivalence relation of fractions. Each fraction from one equivalence class may be considered as a representative for the whole class, and each whole class may be considered as one abstract fraction. This equivalence is preserved by the above defined operations, i.e., the results of operating on fractions are independent of the selection of representatives from their equivalence class. Formally, for addition of fractions
+
+and similarly for the other operations.
+
+In case of fractions of integers the fractions with 
+
+
+
+(
+a
+,
+b
+)
+
+
+{\displaystyle (a,b)}
+
+coprime are often taken as uniquely determined representatives for their equivalent fractions, which are considered to be the same rational number. This way the fractions of integers make up the field of the rational numbers.
+
+More generally, a and b may be elements of any integral domain R, in which case a fraction is an element of the field of fractions of R. For example, polynomials in one indeterminate, with coefficients from some integral domain D, are themselves an integral domain, call it P. So for a and b elements of P, the generated field of fractions is the field of rational fractions (also known as the field of rational functions).
+
+An algebraic fraction is the indicated quotient of two algebraic expressions. As with fractions of integers, the denominator of an algebraic fraction cannot be zero. Two examples of algebraic fractions are 
+
+
+
+
+
+
+3
+x
+
+
+
+x
+
+2
+
+
++
+2
+x
+−
+3
+
+
+
+
+
+{\displaystyle {\frac {3x}{x^{2}+2x-3}}}
+
+ and 
+
+
+
+
+
+
+x
++
+2
+
+
+
+x
+
+2
+
+
+−
+3
+
+
+
+
+
+{\displaystyle {\frac {\sqrt {x+2}}{x^{2}-3}}}
+
+. Algebraic fractions are subject to the same field properties as arithmetic fractions.
+
+If the numerator and the denominator are polynomials, as in 
+
+
+
+
+
+
+3
+x
+
+
+
+x
+
+2
+
+
++
+2
+x
+−
+3
+
+
+
+
+
+{\displaystyle {\frac {3x}{x^{2}+2x-3}}}
+
+, the algebraic fraction is called a rational fraction (or rational expression). An irrational fraction is one that is not rational, as, for example, one that contains the variable under a fractional exponent or root, as in 
+
+
+
+
+
+
+x
++
+2
+
+
+
+x
+
+2
+
+
+−
+3
+
+
+
+
+
+{\displaystyle {\frac {\sqrt {x+2}}{x^{2}-3}}}
+
+.
+
+The terminology used to describe algebraic fractions is similar to that used for ordinary fractions. For example, an algebraic fraction is in lowest terms if the only factors common to the numerator and the denominator are 1 and −1. An algebraic fraction whose numerator or denominator, or both, contain a fraction, such as 
+
+
+
+
+
+
+1
++
+
+
+
+1
+x
+
+
+
+
+
+1
+−
+
+
+
+1
+x
+
+
+
+
+
+
+
+
+{\displaystyle {\frac {1+{\tfrac {1}{x}}}{1-{\tfrac {1}{x}}}}}
+
+, is called a complex fraction.
+
+The field of rational numbers is the field of fractions of the integers, while the integers themselves are not a field but rather an integral domain. Similarly, the rational fractions with coefficients in a field form the field of fractions of polynomials with coefficient in that field. Considering the rational fractions with real coefficients, radical expressions representing numbers, such as 
+
+
+
+
+
+
+2
+
+
+
+/
+
+2
+,
+
+
+
+{\displaystyle \textstyle {\sqrt {2}}/2,}
+
+ are also rational fractions, as are a transcendental numbers such as 
+
+
+
+π
+
+/
+
+2
+,
+
+
+{\textstyle \pi /2,}
+
+ since all of 
+
+
+
+
+
+2
+
+
+,
+π
+,
+
+
+{\displaystyle {\sqrt {2}},\pi ,}
+
+ and 
+
+
+
+2
+
+
+{\displaystyle 2}
+
+ are real numbers, and thus considered as coefficients. These same numbers, however, are not rational fractions with integer coefficients.
+
+The term partial fraction is used when decomposing rational fractions into sums of simpler fractions. For example, the rational fraction 
+
+
+
+
+
+
+2
+x
+
+
+
+x
+
+2
+
+
+−
+1
+
+
+
+
+
+{\displaystyle {\frac {2x}{x^{2}-1}}}
+
+ can be decomposed as the sum of two fractions: 
+
+
+
+
+
+1
+
+x
++
+1
+
+
+
++
+
+
+1
+
+x
+−
+1
+
+
+
+.
+
+
+{\displaystyle {\frac {1}{x+1}}+{\frac {1}{x-1}}.}
+
+ This is useful for the computation of antiderivatives of rational functions.
+
+A fraction may also contain radicals in the numerator and/or the denominator. If the denominator contains radicals, it can be helpful to rationalize it (compare Simplified form of a radical expression), especially if further operations, such as adding or comparing that fraction to another, are to be carried out. It is also more convenient if division is to be done manually. When the denominator is a monomial square root, it can be rationalized by multiplying both the top and the bottom of the fraction by the denominator:
+
+The process of rationalization of binomial denominators involves multiplying the top and the bottom of a fraction by the conjugate of the denominator so that the denominator becomes a rational number. For example:
+
+Even if this process results in the numerator being irrational, like in the examples above, the process may still facilitate subsequent manipulations by reducing the number of irrationals one has to work with in the denominator.
+
+In computer displays and typography, simple fractions are sometimes printed as a single character, e.g. ½ (one half). See the article on Number Forms for information on doing this in Unicode.
+
+Scientific publishing distinguishes four ways to set fractions, together with guidelines on use:[19]
+
+The earliest fractions were reciprocals of integers: ancient symbols representing one part of two, one part of three, one part of four, and so on.[22] The Egyptians used Egyptian fractions c. 1000 BC. About 4000 years ago, Egyptians divided with fractions using slightly different methods. They used least common multiples with unit fractions. Their methods gave the same answer as modern methods.[23] The Egyptians also had a different notation for dyadic fractions in the Akhmim Wooden Tablet and several Rhind Mathematical Papyrus problems.
+
+The Greeks used unit fractions and (later) continued fractions. Followers of the Greek philosopher Pythagoras (c. 530 BC) discovered that the square root of two cannot be expressed as a fraction of integers. (This is commonly though probably erroneously ascribed to Hippasus of Metapontum, who is said to have been executed for revealing this fact.) In 150 BC Jain mathematicians in India wrote the "Sthananga Sutra", which contains work on the theory of numbers, arithmetical operations, and operations with fractions.
+
+A modern expression of fractions known as bhinnarasi seems to have originated in India in the work of Aryabhatta (c. AD 500),[citation needed] Brahmagupta (c. 628), and Bhaskara (c. 1150).[24] Their works form fractions by placing the numerators (Sanskrit: amsa) over the denominators (cheda), but without a bar between them.[24] In Sanskrit literature, fractions were always expressed as an addition to or subtraction from an integer.[citation needed] The integer was written on one line and the fraction in its two parts on the next line. If the fraction was marked by a small circle ⟨०⟩ or cross ⟨+⟩, it is subtracted from the integer; if no such sign appears, it is understood to be added. For example, Bhaskara I writes[25]
+
+which is the equivalent of
+
+and would be written in modern notation as 61/4, 11/5, and 2 − 1/9 (i.e., 18/9).
+
+The horizontal fraction bar is first attested in the work of Al-Hassār (fl. 1200),[24] a Muslim mathematician from Fez, Morocco, who specialized in Islamic inheritance jurisprudence. In his discussion he writes, "... for example, if you are told to write three-fifths and a third of a fifth, write thus, 
+
+
+
+
+
+
+3
+
+1
+
+
+5
+
+3
+
+
+
+
+
+{\displaystyle {\frac {3\quad 1}{5\quad 3}}}
+
+."[26] The same fractional notation—with the fraction given before the integer[24]—appears soon after in the work of Leonardo Fibonacci in the 13th century.[27]
+
+In discussing the origins of decimal fractions, Dirk Jan Struik states:[28]
+
+"The introduction of decimal fractions as a common computational practice can be dated back to the Flemish pamphlet De Thiende, published at Leyden in 1585, together with a French translation, La Disme, by the Flemish mathematician Simon Stevin (1548–1620), then settled in the Northern Netherlands. It is true that decimal fractions were used by the Chinese many centuries before Stevin and that the Persian astronomer Al-Kāshī used both decimal and sexagesimal fractions with great ease in his Key to arithmetic (Samarkand, early fifteenth century)."[29]
+
+While the Persian mathematician Jamshīd al-Kāshī claimed to have discovered decimal fractions himself in the 15th century, J. Lennart Berggren notes that he was mistaken, as decimal fractions were first used five centuries before him by the Baghdadi mathematician Abu'l-Hasan al-Uqlidisi as early as the 10th century.[30][n 2]
+
+In primary schools, fractions have been demonstrated through Cuisenaire rods, Fraction Bars, fraction strips, fraction circles, paper (for folding or cutting), pattern blocks, pie-shaped pieces, plastic rectangles, grid paper, dot paper, geoboards, counters and computer software.
+
+Several states in the United States have adopted learning trajectories from the Common Core State Standards Initiative's guidelines for mathematics education. Aside from sequencing the learning of fractions and operations with fractions, the document provides the following definition of a fraction: "A number expressible in the form ​
+
+
+
+a
+
+
+{\displaystyle a}
+
+⁄
+
+
+
+b
+
+
+{\displaystyle b}
+
+ where 
+
+
+
+a
+
+
+{\displaystyle a}
+
+ is a whole number and 
+
+
+
+b
+
+
+{\displaystyle b}
+
+ is a positive whole number. (The word fraction in these standards always refers to a non-negative number.)"[32] The document itself also refers to negative fractions.

en/2059.html.txt

@@ -0,0 +1,162 @@
+
+
+French (français [fʁɑ̃sɛ] or langue française [lɑ̃ɡ fʁɑ̃sɛːz]) is a Romance language of the Indo-European family. It descended from the Vulgar Latin of the Roman Empire, as did all Romance languages. French evolved from Gallo-Romance, the Latin spoken in Gaul, and more specifically in Northern Gaul. Its closest relatives are the other langues d'oïl—languages historically spoken in northern France and in southern Belgium, which French (Francien) largely supplanted. French was also influenced by native Celtic languages of Northern Roman Gaul like Gallia Belgica and by the (Germanic) Frankish language of the post-Roman Frankish invaders. Today, owing to France's past overseas expansion, there are numerous French-based creole languages, most notably Haitian Creole. A French-speaking person or nation may be referred to as Francophone in both English and French.
+
+French is an official language in 29 countries across multiple continents,[5] most of which are members of the Organisation internationale de la Francophonie (OIF), the community of 84 countries which share the official use or teaching of French. French is also one of six official languages used in the United Nations.[6] It is spoken as a first language (in descending order of the number of speakers) in France, the Canadian provinces of Quebec, Ontario and New Brunswick as well as other Francophone regions, Belgium (Wallonia and the Brussels-Capital Region), western Switzerland (cantons of Bern, Fribourg, Geneva, Jura, Neuchâtel, Vaud, Valais), Monaco, partly in Luxembourg, the states of Louisiana, Maine, New Hampshire and Vermont in the United States, and in northwestern Italy (region of Aosta Valley), and by various communities elsewhere.[7]
+
+In 2015, approximately 40% of the francophone population (including L2 and partial speakers) lived in Europe, 35% in sub-Saharan Africa, 15% in North Africa and the Middle East, 8% in the Americas, and 1% in Asia and Oceania.[8] French is the fourth most widely spoken mother tongue in the European Union.[9] Of Europeans who speak other languages natively, approximately one-fifth are able to speak French as a second language.[10] French is the second most taught foreign language in the EU.[11] French is also the 18th most natively spoken language in the world, 6th most spoken language by total number of speakers and the second or third most studied language worldwide (with about 120 million current learners).[12] As a result of French and Belgian colonialism from the 16th century onward, French was introduced to new territories in the Americas, Africa and Asia. Most second-language speakers reside in Francophone Africa, in particular Gabon, Algeria, Morocco, Tunisia, Mauritius, Senegal and Ivory Coast.[13]
+
+French is estimated to have about 76 million native speakers and about 235 million daily, fluent speakers[14][1][15] and another 77 to 110 million secondary speakers who speak it as a second language to varying degrees of proficiency, mainly in Africa.[16] According to the Organisation internationale de la Francophonie (OIF), approximately 300 million people worldwide are "able to speak the language",[17] without specifying the criteria for this estimation or whom it encompasses.[2] According to a demographic projection led by the Université Laval and the Réseau Démographie de l'Agence universitaire de la francophonie, the total number of French speakers will reach approximately 500 million in 2025 and 650 million by 2050.[18] OIF estimates 700 million by 2050, 80% of whom will be in Africa.[8]
+
+French has a long history as an international language of literature and scientific standards and is a primary or second language of many international organisations including the United Nations, the European Union, the North Atlantic Treaty Organization, the World Trade Organization, the International Olympic Committee, and the International Committee of the Red Cross. In 2011, Bloomberg Businessweek ranked French the third most useful language for business, after English and Standard Mandarin Chinese.[19]
+
+French is a Romance language (meaning that it is descended primarily from Vulgar Latin) that evolved out of the Gallo-Romance dialects spoken in northern France. The language's early forms include Old French and Middle French.
+
+Due to Roman rule, Latin was gradually adopted by the inhabitants of Gaul, and as the language was learned by the common people it developed a distinct local character, with grammatical differences from Latin as spoken elsewhere, some of which being attested on graffiti.[20] This local variety evolved into the Gallo-Romance tongues, which include French and its closest relatives, such as Arpitan.
+
+The evolution of Latin in Gaul was shaped by its coexistence for over half a millennium beside the native Celtic Gaulish language, which did not go extinct until the late 6th century, long after the Fall of the Western Roman Empire.[21] The population remained 90% indigenous in origin,[22][23] and instead of Roman settlers, the Romanizing class was the local native elite, whose children learned Latin in Roman schools; at the time of the collapse of the Empire, this local elite had been slowly abandoning Gaulish entirely, but the rural and lower class populations remained Gaulish speakers who could sometimes also speak Latin or Greek.[24]  The final language shift from Gaulish to Vulgar Latin among rural and lower class populations occurred later, when both they and the incoming Frankish ruler/military class adopted the Gallo-Roman Vulgar Latin speech of the urban intellectual elite.[24]
+
+The Gaulish language likely survived into the 6th century in France, despite considerable Romanization.[21] Coexisting with Latin, Gaulish helped shape the Vulgar Latin dialects that developed into French,[24][21] with effects including loanwords and calques (including oui,[25] the word for "yes"),[26][25] sound changes shaped by Gaulish influence,[27][28] and influences in conjugation and word order.[26][25][20] Recent computational studies suggest that early gender shifts may have been motivated by the gender of the corresponding word in Gaulish.[29]
+
+The beginning of French in Gaul was greatly influenced by Germanic invasions into the country. These invasions had the greatest impact on the northern part of the country and on the language there.[30] A language divide began to grow across the country. The population in the north spoke langue d'oïl while the population in the south spoke langue d'oc.[30] Langue d'oïl grew into what is known as Old French. The period of Old French spanned between the 8th and 14th centuries. Old French shared many characteristics with Latin. For example, Old French made use of different possible word orders just as Latin did because it had a case system that retained the difference between nominative subjects and oblique non-subjects.[31] The period is marked by a heavy superstrate influence from the Germanic Frankish language, which non-exhaustively included the use in upper-class speech and higher registers of V2 word order,[32] a large percentage of the vocabulary (now at around 15% of modern French vocabulary [33]) including the impersonal singular pronoun on (a calque of Germanic man), and the name of the language itself.
+
+Within Old French many dialects emerged but the Francien dialect is one that not only continued but also thrived during the Middle French period (14th century–17th century).[30] Modern French grew out of this Francien dialect.[30] Grammatically, during the period of Middle French, noun declensions were lost and there began to be standardized rules. Robert Estienne published the first Latin-French dictionary, which included information about phonetics, etymology, and grammar.[34] Politically, the Ordinance of Villers-Cotterêts (1539) named French the language of law.
+
+During the 17th century, French replaced Latin as the most important language of diplomacy and international relations (lingua franca). It retained this role until approximately the middle of the 20th century, when it was replaced by English as the United States became the dominant global power following the Second World War.[35][36] Stanley Meisler of the Los Angeles Times said that the fact that the Treaty of Versailles was written in English as well as French was the "first diplomatic blow" against the language.[37]
+
+During the Grand Siècle (17th century), France, under the rule of powerful leaders such as Cardinal Richelieu and Louis XIV, enjoyed a period of prosperity and prominence among European nations. Richelieu established the Académie française to protect the French language. By the early 1800s, Parisian French had become the primary language of the aristocracy in France.
+
+Near the beginning of the 19th century, the French government began to pursue policies with the end goal of eradicating the many minorities and regional languages (patois) spoken in France. This began in 1794 with Henri Grégoire's "Report on the necessity and means to annihilate the patois and to universalize the use of the French language". When public education was made compulsory, only French was taught and the use of any other (patois) language was punished. The goals of the Public School System were made especially clear to the French-speaking teachers sent to teach students in regions such as Occitania and Brittany: "And remember, Gents: you were given your position in order to kill the Breton language" were instructions given from a French official to teachers in the French department of Finistère (western Brittany).[38] The prefect of Basses-Pyrénées in the French Basque Country wrote in 1846: "Our schools in the Basque Country are particularly meant to replace the Basque language with French...".[38] Students were taught that their ancestral languages were inferior and they should be ashamed of them; this process was known in the Occitan-speaking region as Vergonha.
+
+Among the historic reformers of French orthography, such as Louis Maigret, Marle M., Marcellin Berthelot, Philibert Monet, Jacques Peletier du Mans, and Somaize, nowadays the most striking reform is proposed by Mickael Korvin, a Franco-American linguist of Hungarian origin who wants to eliminate accents, silent letters, double letters and more.[39]
+
+Spoken by 19.71% of the European Union's population, French is the third most widely spoken language in the EU, after English and German.[9][41]
+
+Under the Constitution of France, French has been the official language of the Republic since 1992,[42] although the ordinance of Villers-Cotterêts made it mandatory for legal documents in 1539. France mandates the use of French in official government publications, public education except in specific cases, and legal contracts; advertisements must bear a translation of foreign words.
+
+In Belgium, French is the official language of Wallonia (excluding a part of the East Cantons, which are German-speaking) and one of the two official languages—along with Dutch—of the Brussels-Capital Region, where it is spoken by the majority of the population often as their primary language.[43]
+
+French is one of the four official languages of Switzerland, along with German, Italian, and Romansh, and is spoken in the western part of Switzerland, called Romandy, of which Geneva is the largest city. The language divisions in Switzerland do not coincide with political subdivisions, and some cantons have bilingual status: for example, cities such as Biel/Bienne and cantons such as Valais, Fribourg and Berne. French is the native language of about 23% of the Swiss population, and is spoken by 50%[44] of the population.
+
+French is also an official language of Monaco and Luxembourg, as well as in the Aosta Valley region of Italy, while French dialects remain spoken by minorities on the Channel Islands. It is also spoken in Andorra and is the main language after Catalan in El Pas de la Casa. The language is taught as the primary second language in the German land of Saarland, with French being taught from pre-school and over 43% of citizens being able to speak French.[45][46]
+
+The majority of the world's French-speaking population lives in Africa. According to the 2007 report by the Organisation Internationale de la Francophonie, an estimated 115 million African people spread across 31 Francophone countries can speak French as either a first or a second language.[13] This number does not include the people living in non-Francophone African countries who have learned French as a foreign language.[13] Due to the rise of French in Africa, the total French-speaking population worldwide is expected to reach 700 million people in 2050.[49] French is the fastest growing language on the continent (in terms of either official or foreign languages).[50][51]
+French is mostly a second language in Africa, but it has become a first language in some urban areas, such as the region of Abidjan, Ivory Coast[52] and in Libreville, Gabon.[53] There is not a single African French, but multiple forms that diverged through contact with various indigenous African languages.[54]
+
+Sub-Saharan Africa is the region where the French language is most likely to expand, because of the expansion of education and rapid population growth.[55] It is also where the language has evolved the most in recent years.[56][57] Some vernacular forms of French in Africa can be difficult to understand for French speakers from other countries,[58] but written forms of the language are very closely related to those of the rest of the French-speaking world.
+
+French is the second most common language in Canada, after English, and both are official languages at the federal level. It is the first language of 9.5 million people or 29% and the second language for 2.07 million or 6% of the entire population of Canada.[15] French is the sole official language in the province of Quebec, being the mother tongue for some 7 million people, or almost 80% (2006 Census) of the province. About 95% of the people of Quebec speak French as either their first or second language, and for some as their third language. Quebec is also home to the city of Montreal, which is the world's 4th-largest French-speaking city, by number of first language speakers.[59] New Brunswick and Manitoba are the only officially bilingual provinces, though full bilingualism is enacted only in New Brunswick, where about one third of the population is Francophone. French is also an official language of all of the territories (Northwest Territories, Nunavut, and Yukon). Out of the three, Yukon has the most French speakers, comprising just under 4% of the population.[60] Furthermore, while French is not an official language in Ontario, the French Language Services Act ensures that provincial services are to be available in the language. The Act applies to areas of the province where there are significant Francophone communities, namely Eastern Ontario and Northern Ontario. Elsewhere, sizable French-speaking minorities are found in southern Manitoba, Nova Scotia, Prince Edward Island and the Port au Port Peninsula in Newfoundland and Labrador, where the unique Newfoundland French dialect was historically spoken. Smaller pockets of French speakers exist in all other provinces. The Ontarian city of Ottawa, the Canadian capital, is also effectively bilingual, as it has a large population of federal government workers, who are required to offer services in both French and English, and is across a river from Quebec, opposite the major city of Gatineau with which it forms a single metropolitan area.[citation needed]
+
+According to the United States Census Bureau (2011), French is the fourth[61] most-spoken language in the United States after English, Spanish, and Chinese, when all forms of French are considered together and all dialects of Chinese are similarly combined. French remains the second most-spoken language in the states of Louisiana, Maine, Vermont and New Hampshire. Louisiana is home to many distinct dialects, collectively known as Louisiana French. According to the 2000 United States Census, there are over 194,000 people in Louisiana who speak French at home, the most of any state if Creole French is excluded.[62] New England French, essentially a variant of Canadian French, is spoken in parts of New England. Missouri French was historically spoken in Missouri and Illinois (formerly known as Upper Louisiana), but is nearly extinct today.[63]  French also survived in isolated pockets along the Gulf Coast of what was previously French Lower Louisiana, such as Mon Louis Island, Alabama and DeLisle, Mississippi (the latter only being discovered by linguists in the 1990s) but these varieties are severely endangered or presumed extinct.
+
+French is one of Haiti's two official languages. It is the principal language of writing, school instruction, and administrative use. It is spoken by all educated Haitians and is used in the business sector. It is also used for ceremonial events such as weddings, graduations and church masses. About 70–80% of the country's population have Haitian Creole as their first language; the rest speak French as a first language. The second official language is the recently standardized Haitian Creole, which virtually the entire population of Haiti speaks. Haitian Creole is one of the French-based creole languages, drawing the large majority of its vocabulary from French, with influences from West African languages, as well as several European languages. Haitian Creole is closely related to Louisiana Creole and the creole from the Lesser Antilles.[64]
+
+French is the official language of both French Guiana on the South American continent,[65] and of Saint Pierre and Miquelon,[66] an archipelago off the coast of Newfoundland in North America.
+
+French was spoken in French India and is still one of the official languages of Puducherry.[67]
+
+French was the official language of the colony of French Indochina, comprising modern-day Vietnam, Laos, and Cambodia. It continues to be an administrative language in Laos and Cambodia, although its influence has waned in recent years.[68] In colonial Vietnam, the elites primarily spoke French, while many servants who worked in French households spoke a French pidgin known as "Tây Bồi" (now extinct). After French rule ended, South Vietnam continued to use French in administration, education, and trade.[69] Since the Fall of Saigon and the opening of a unified Vietnam's economy, French has gradually been effectively displaced as the main foreign language of choice by English. French nevertheless maintains its colonial legacy by being spoken as a second language by the elderly and elite populations and is presently being revived in higher education and continues to be a diplomatic language in Vietnam. All three countries are official members of the OIF.[70]
+
+A former French mandate, Lebanon designates Arabic as the sole official language, while a special law regulates cases when French can be publicly used. Article 11 of Lebanon's Constitution states that "Arabic is the official national language. A law determines the cases in which the French language is to be used".[71] The French language in Lebanon is a widespread second language among the Lebanese people, and is taught in many schools along with Arabic and English. French is used on Lebanese pound banknotes, on road signs, on Lebanese license plates, and on official buildings (alongside Arabic).
+
+Today, French and English are secondary languages of Lebanon, with about 40% of the population being Francophone and 40% Anglophone.[72] The use of English is growing in the business and media environment. Out of about 900,000 students, about 500,000 are enrolled in Francophone schools, public or private, in which the teaching of mathematics and scientific subjects is provided in French.[73] Actual usage of French varies depending on the region and social status. One-third of high school students educated in French go on to pursue higher education in English-speaking institutions. English is the language of business and communication, with French being an element of social distinction, chosen for its emotional value.[74]
+
+A significant French-speaking community is also present in Israel, primarily among the communities of French Jews in Israel, Moroccan Jews in Israel and Lebanese Jews. Many secondary schools offer French as a foreign language.
+
+The UAE has the status in the Organisation internationale de la Francophonie as an observer state, and Qatar has the status in the organization as an associate state. However, in both countries, French is not spoken by almost any of the general population or migrant workers, but spoken by a small minority of those who invest in Francophone countries or have other financial or family ties. Their entrance as observer and associate states respectively into the organization was aided a good deal by their investments into the Organisation and France itself.[75] A country's status as an observer state in the Organisation internationale de la Francophonie gives the country the right to send representatives to organization meetings and make formal requests to the organization but they do not have voting rights within the OIF.[76] A country's status as an associate state also does not give a country voting abilities but associate states can discuss and review organization matters.[77]
+
+French is an official language of the Pacific Island nation of Vanuatu, where 45% of the population can speak it.[78] In the French special collectivity of New Caledonia, 97% of the population can speak, read and write French[79] while in French Polynesia this figure is 95%,[80] and in the French collectivity of Wallis and Futuna, it is 84%.[81]
+
+In French Polynesia and to a lesser extent Wallis and Futuna, where oral and written knowledge of the French language has become almost nearly universal (95% and 84% respectively), French increasingly tends to displace the native Polynesian languages as the language most spoken at home. In French Polynesia, the percentage of the population who reported that French was the language they use the most at home rose from 67% at the 2007 census to 74% at the 2017 census.[82][80] In Wallis and Futuna, the percentage of the population who reported that French was the language they use the most at home rose from 10% at the 2008 census to 13% at the 2018 census.[81][83]
+
+The future of the French language is often discussed in the news. For example, in 2014, The New York Times documented an increase in the teaching of French in New York, especially in K-12 dual-language programs where Spanish and Mandarin are the only second-language options more popular than French.[84] In a study published in March 2014 by Forbes, the investment bank Natixis said that French could become the world's most spoken language by 2050. It noted that French is spreading in areas where the population is rapidly increasing, especially in sub-Saharan Africa.[85]
+
+French is taught in universities around the world, and is one of the world's most influential languages because of its wide use in the worlds of journalism, jurisprudence, education, and diplomacy.[86]
+In diplomacy, French is one of the six official languages of the United Nations (and one of the UN Secretariat's only two working languages[87]), one of twenty official and three working languages of the European Union, an official language of NATO, the International Olympic Committee, the Council of Europe, the Organisation for Economic Co-operation and Development, Organization of American States (alongside Spanish, Portuguese and English), the Eurovision Song Contest, one of eighteen official languages of the European Space Agency, World Trade Organization and the least used of the three official languages in the North American Free Trade Agreement countries. It is also a working language in nonprofit organisations such as the Red Cross (alongside English, German, Spanish, Portuguese, Arabic and Russian), Amnesty International (alongside 32 other languages of which English is the most used, followed by Spanish, Portuguese, German, and Italian), Médecins sans Frontières (used alongside English, Spanish, Portuguese and Arabic), and Médecins du Monde (used alongside English).[88] Given the demographic prospects of the French-speaking nations of Africa, researcher Pascal-Emmanuel Gobry wrote in 2014 that French "could be the language of the future".[89]
+
+Significant as a judicial language, French is one of the official languages of such major international and regional courts, tribunals, and dispute-settlement bodies as the African Court on Human and Peoples' Rights, the Caribbean Court of Justice, the Court of Justice for the Economic Community of West African States, the Inter-American Court of Human Rights, the International Court of Justice, the International Criminal Tribunal for the former Yugoslavia, International Criminal Tribunal for Rwanda, the International Tribunal for the Law of the Sea the International Criminal Court and the World Trade Organization Appellate Body. It is the sole internal working language of the Court of Justice of the European Union, and makes with English the European Court of Human Rights's two working languages.[90]
+
+In 1997, George Werber published, in Language Today, a comprehensive academic study entitled "The World's 10 most influential languages".[91] In the article, Werber ranked French as, after English, the second most influential language of the world, ahead of Spanish.[91] His criteria were the numbers of native speakers, the number of secondary speakers (especially high for French among fellow world languages), the number of countries using the language and their respective populations, the economic power of the countries using the language, the number of major areas in which the language is used,  and the linguistic prestige associated with the mastery of the language (Werber highlighted that French in particular enjoys considerable linguistic prestige).[91] In a 2008 reassessment of his article, Werber concluded that his findings were still correct since "the situation among the top ten remains unchanged."[91]
+
+Knowledge of French is often considered to be a useful skill by business owners in the United Kingdom; a 2014 study found that 50% of British managers considered French to be a valuable asset for their business, thus ranking French as the most sought-after foreign language there, ahead of German (49%) and Spanish (44%).[92] MIT economist Albert Saiz calculated a 2.3% premium for those who have French as a foreign language in the workplace.[93]
+
+In English-speaking Canada, the United Kingdom, and the Republic of Ireland, French is the first foreign language taught and in number of pupils is far ahead of other languages. In the United States, Spanish is the most commonly taught foreign language in schools and universities, though French is next. In some areas of the country nearest to French-speaking Quebec, it is the language more commonly taught.
+
+Vowel phonemes in French
+
+Although there are many French regional accents, foreign learners normally use only one variety of the language.
+
+French pronunciation follows strict rules based on spelling, but French spelling is often based more on history than phonology. The rules for pronunciation vary between dialects, but the standard rules are:
+
+French is written with the 26 letters of the basic Latin script, with four diacritics appearing on vowels (circumflex accent, acute accent, grave accent, diaeresis) and the cedilla appearing in "ç".
+
+There are two ligatures, "œ" and "æ", but they are often replaced in contemporary French with "oe" and "ae", because the ligatures do not appear on the AZERTY keyboard layout used in French-speaking countries. However this is nonstandard in formal and literary texts.
+
+French spelling, like English spelling, tends to preserve obsolete pronunciation rules. This is mainly due to extreme phonetic changes since the Old French period, without a corresponding change in spelling. Moreover, some conscious changes were made to restore Latin orthography (as with some English words such as "debt"):
+
+French is a morphophonemic language. While it contains 130 graphemes that denote only 36 phonemes, many of its spelling rules are likely due to a consistency in morphemic patterns such as adding suffixes and prefixes.[94] Many given spellings of common morphemes usually lead to a predictable sound. In particular, a given vowel combination or diacritic generally leads to one phoneme. However, there is not a one-to-one relation of a phoneme and a single related grapheme, which can be seen in how tomber and tombé both end with the /e/ phoneme.[95] Additionally, there are many variations in the pronunciation of consonants at the end of words, demonstrated by how the x in paix is not pronounced though at the end of Aix it is.
+
+As a result, it can be difficult to predict the spelling of a word based on the sound. Final consonants are generally silent, except when the following word begins with a vowel (see Liaison (French)). For example, the following words end in a vowel sound: pied, aller, les, finit, beaux. The same words followed by a vowel, however, may sound the consonants, as they do in these examples: beaux-arts, les amis, pied-à-terre.
+
+French writing, as with any language, is affected by the spoken language. In Old French, the plural for animal was animals. The /als/ sequence was unstable and was turned into a diphthong /aus/. This change was then reflected in the orthography: animaus. The us ending, very common in Latin, was then abbreviated by copyists (monks) by the letter x, resulting in a written form animax. As the French language further evolved, the pronunciation of au turned into /o/ so that the u was reestablished in orthography for consistency, resulting in modern French animaux (pronounced first /animos/ before the final /s/ was dropped in contemporary French). The same is true for cheval pluralized as chevaux and many others. In addition, castel pl. castels became château pl. châteaux.
+
+Some proposals exist to simplify the existing writing system, but they still fail to gather interest.[96][97][98][99]
+
+In 1990, a reform accepted some changes to French orthography. At the time the proposed changes were considered to be suggestions. In 2016, schoolbooks in France began to use the newer recommended spellings, with instruction to teachers that both old and new spellings be deemed correct.[100]
+
+French is a moderately inflected language. Nouns and most pronouns are inflected for number (singular or plural, though in most nouns the plural is pronounced the same as the singular even if spelled differently); adjectives, for number and gender (masculine or feminine) of their nouns; personal pronouns and a few other pronouns, for person, number, gender, and case; and verbs, for tense, aspect, mood, and the person and number of their subjects. Case is primarily marked using word order and prepositions, while certain verb features are marked using auxiliary verbs. According to the French lexicogrammatical system, French has a rank-scale hierarchy with clause as the top rank, which is followed by group rank, word rank, and morpheme rank. A French clause is made up of groups, groups are made up of words, and lastly, words are made up of morphemes.[101]
+
+French grammar shares several notable features with most other Romance languages, including
+
+Every French noun is either masculine or feminine. Because French nouns are not inflected for gender, a noun's form cannot specify its gender. For nouns regarding the living, their grammatical genders often correspond to that which they refer to. For example, a male teacher is a "enseignant" while a female teacher is a "enseignante". However, plural nouns that refer to a group that includes both masculine and feminine entities are always masculine. So a group of two male teachers would be "enseignants". A group of two male teachers and two female teachers would still be "enseignants". In many situations, and in the case of "enseignant", both the singular and plural form of a noun are pronounced identically. The article used for singular nouns is different from that used for plural nouns and the article provides a distinguishing factor between the two in speech. For example, the singular "le professeur" or "la professeur(e)" (the male or female teacher, professor) can be distinguished from the plural "les professeurs" because "le", "la", and "les" are all pronounced differently. There are some situations where both the feminine and masculine form of a noun are the same and the article provides the only difference. For example, "le dentiste" refers to a male dentist while "la dentiste" refers to a female dentist.
+
+The French language consists of both finite and non-finite moods. The finite moods include the indicative mood (indicatif), the subjunctive mood (subjonctif), the imperative mood (impératif), and the conditional mood (conditionnel). The non-finite moods include the infinitive mood (infinitif), the present participle (participe présent), and the past participle (participe passé).
+
+The indicative mood makes use of eight tense-aspect forms. These include the present (présent), the simple past (passé composé and passé simple), the past imperfective (imparfait), the pluperfect (plus-que-parfait), the simple future (futur simple), the future perfect (futur antérieur), and the past perfect (passé antérieur). Some forms are less commonly used today. In today's spoken French, the passé composé is used while the passé simple is reserved for formal situations or for literary purposes. Similarly, the plus-que-parfait is used for speaking rather than the older passé antérieur seen in literary works.
+
+Within the indicative mood, the passé composé, plus-que-parfait, futur antérieur, and passé antérieur all use auxiliary verbs in their forms.
+
+The subjunctive mood only includes four of the tense-aspect forms found in the indicative: present (présent), simple past (passé composé), past imperfective (imparfait), and pluperfect (plus-que-parfait).
+
+Within the subjunctive mood, the passé composé and plus-que-parfait use auxiliary verbs in their forms.
+
+The imperative is used in the present tense (with the exception of a few instances where it is used in the perfect tense). The imperative is used to give commands to you (tu), we/us (nous), and plural you (vous).
+
+The conditional makes use of the present (présent) and the past (passé).
+
+The passé uses auxiliary verbs in its forms.
+
+French uses both the active voice and the passive voice. The active voice is unmarked while the passive voice is formed by using a form of verb être ("to be") and the past participle.
+
+Example of the active voice:
+
+Example of the passive voice:
+
+French declarative word order is subject–verb–object although a pronoun object precedes the verb. Some types of sentences allow for or require different word orders, in particular inversion of the subject and verb like "Parlez-vous français?" when asking a question rather than just "Vous parlez français ?" Both questions mean the same thing; however, a rising inflection is always used on both of them whenever asking a question, especially on the second one. Specifically, the first translates into "Do you speak French?" while the second one is literally just "You speak French?" To avoid inversion while asking a question, 'Est-ce que' (literally 'is it that') may be placed in the beginning of the sentence. "Parlez-vous français ?" may become "Est-ce que vous parlez français ?" French also uses verb–object–subject (VOS) and object–subject–verb (OSV) word order. OSV word order is not used often and VOS is reserved for formal writings.[31]
+
+The majority of French words derive from Vulgar Latin or were constructed from Latin or Greek roots. In many cases a single etymological root appears in French in a "popular" or native form, inherited from Vulgar Latin, and a learned form, borrowed later from Classical Latin. The following pairs consist of a native noun and a learned adjective:
+
+However, a historical tendency to gallicise Latin roots can be identified, whereas English conversely leans towards a more direct incorporation of the Latin:
+
+There are also noun-noun and adjective-adjective pairs:
+
+It can be difficult to identify the Latin source of native French words, because in the evolution from Vulgar Latin, unstressed syllables were severely reduced and the remaining vowels and consonants underwent significant modifications.
+
+More recently the linguistic policy of the French language academies of France and Quebec has been to provide French equivalents to (mainly English) imported words, either by using existing vocabulary, extending its meaning or deriving a new word according to French morphological rules. The result is often two (or more) co-existing terms for describing the same phenomenon.
+
+Root languages of loanwords[102]
+
+It is estimated that 12% (4,200) of common French words found in a typical dictionary such as the Petit Larousse or Micro-Robert Plus (35,000 words) are of foreign origin (where Greek and Latin learned words are not seen as foreign). About 25% (1,054) of these foreign words come from English and are fairly recent borrowings. The others are some 707 words from Italian, 550 from ancient Germanic languages, 481 from other Gallo-Romance languages, 215 from Arabic, 164 from German, 160 from Celtic languages, 159 from Spanish, 153 from Dutch, 112 from Persian and Sanskrit, 101 from Native American languages, 89 from other Asian languages, 56 from other Afro-Asiatic languages, 55 from Slavic languages and Baltic languages, 10 from Basque and 144 (about 3%) from other languages.[102]
+
+One study analyzing the degree of differentiation of Romance languages in comparison to Latin estimated that among the languages analyzed French has the greatest distance from Latin.[103] Lexical similarity is 89% with Italian, 80% with Sardinian, 78% with Rhaeto-Romance, and 75% with Romanian, Spanish and Portuguese.[104][105][104]
+
+The French counting system is partially vigesimal: twenty (vingt) is used as a base number in the names of numbers from 70 to 99. The French word for 80 is quatre-vingts, literally "four twenties", and the word for 75 is soixante-quinze, literally "sixty-fifteen". This reform arose after the French Revolution to unify the counting systems (mostly vigesimal near the coast, because of Celtic (via Breton) and Viking influences. This system is comparable to the archaic English use of score, as in "fourscore and seven" (87), or "threescore and ten" (70).
+
+In Old French (during the Middle Ages), all numbers from 30 to 99 could be said in either base 10 or base 20, e.g. vint et doze (twenty and twelve) for 32, dous vinz et diz (two twenties and ten) for 50, uitante for 80, or nonante for 90.[106]
+
+Belgian French, Swiss French, Aostan French[107] and the French used in the Democratic Republic of the Congo, Rwanda and Burundi are different in this respect. In the French spoken in these places, 70 and 90 are septante and nonante. In Switzerland, depending on the local dialect, 80 can be quatre-vingts (Geneva, Neuchâtel, Jura) or huitante (Vaud, Valais, Fribourg). Octante had been used in Switzerland in the past, but is now considered archaic,[108] while in the Aosta Valley 80 is huitante.[107] In Belgium and in its former African colonies, however, quatre-vingts is universally used.
+
+French, like most European languages, uses a space to separate thousands.[109] The comma is used in French numbers as a decimal point, i.e. "2,5" instead of "2.5".
+
+Notes
+

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+Amphibians are ectothermic, tetrapod vertebrates of the class Amphibia. Modern amphibians are all Lissamphibia. They inhabit a wide variety of habitats, with most species living within terrestrial, fossorial, arboreal or freshwater aquatic ecosystems. Thus amphibians typically start out as larvae living in water, but some species have developed behavioural adaptations to bypass this.
+
+The young generally undergo metamorphosis from larva with gills to an adult air-breathing form with lungs. Amphibians use their skin as a secondary respiratory surface and some small terrestrial salamanders and frogs lack lungs and rely entirely on their skin. They are superficially similar to lizards but, along with mammals and birds, reptiles are amniotes and do not require water bodies in which to breed. With their complex reproductive needs and permeable skins, amphibians are often ecological indicators; in recent decades there has been a dramatic decline in amphibian populations for many species around the globe.
+
+The earliest amphibians evolved in the Devonian period from sarcopterygian fish with lungs and bony-limbed fins, features that were helpful in adapting to dry land. They diversified and became dominant during the Carboniferous and Permian periods, but were later displaced by reptiles and other vertebrates. Over time, amphibians shrank in size and decreased in diversity, leaving only the modern subclass Lissamphibia.
+
+The three modern orders of amphibians are Anura (the frogs and toads), Urodela (the salamanders), and Apoda (the caecilians). The number of known amphibian species is approximately 8,000, of which nearly 90% are frogs. The smallest amphibian (and vertebrate) in the world is a frog from New Guinea (Paedophryne amauensis) with a length of just 7.7 mm (0.30 in). The largest living amphibian is the 1.8 m (5 ft 11 in) South China giant salamander (Andrias sligoi), but this is dwarfed by the extinct 9 m (30 ft) Prionosuchus from the middle Permian of Brazil. The study of amphibians is called batrachology, while the study of both reptiles and amphibians is called herpetology.
+
+The word "amphibian" is derived from the Ancient Greek term ἀμφίβιος (amphíbios), which means "both kinds of life", ἀμφί meaning "of both kinds" and βιος meaning "life". The term was initially used as a general adjective for animals that could live on land or in water, including seals and otters.[2] Traditionally, the class Amphibia includes all tetrapod vertebrates that are not amniotes. Amphibia in its widest sense (sensu lato) was divided into three subclasses, two of which are extinct:[3]
+
+The actual number of species in each group depends on the taxonomic classification followed. The two most common systems are the classification adopted by the website AmphibiaWeb, University of California, Berkeley and the classification by herpetologist Darrel Frost and the American Museum of Natural History, available as the online reference database "Amphibian Species of the World".[4] The numbers of species cited above follows Frost and the total number of known amphibian species as of March 31, 2019 is exactly 8,000,[5] of which nearly 90% are frogs.[6]
+
+With the phylogenetic classification, the taxon Labyrinthodontia has been discarded as it is a polyparaphyletic group without unique defining features apart from shared primitive characteristics. Classification varies according to the preferred phylogeny of the author and whether they use a stem-based or a node-based classification. Traditionally, amphibians as a class are defined as all tetrapods with a larval stage, while the group that includes the common ancestors of all living amphibians (frogs, salamanders and caecilians) and all their descendants is called Lissamphibia. The phylogeny of Paleozoic amphibians is uncertain, and Lissamphibia may possibly fall within extinct groups, like the Temnospondyli (traditionally placed in the subclass Labyrinthodontia) or the Lepospondyli, and in some analyses even in the amniotes. This means that advocates of phylogenetic nomenclature have removed a large number of basal Devonian and Carboniferous amphibian-type tetrapod groups that were formerly placed in Amphibia in Linnaean taxonomy, and included them elsewhere under cladistic taxonomy.[1] If the common ancestor of amphibians and amniotes is included in Amphibia, it becomes a paraphyletic group.[7]
+
+All modern amphibians are included in the subclass Lissamphibia, which is usually considered a clade, a group of species that have evolved from a common ancestor. The three modern orders are Anura (the frogs and toads), Caudata (or Urodela, the salamanders), and Gymnophiona (or Apoda, the caecilians).[8] It has been suggested that salamanders arose separately from a Temnospondyl-like ancestor, and even that caecilians are the sister group of the advanced reptiliomorph amphibians, and thus of amniotes.[9] Although the fossils of several older proto-frogs with primitive characteristics are known, the oldest "true frog" is Prosalirus bitis, from the Early Jurassic Kayenta Formation of Arizona. It is anatomically very similar to modern frogs.[10] The oldest known caecilian is another Early Jurassic species, Eocaecilia micropodia, also from Arizona.[11] The earliest salamander is Beiyanerpeton jianpingensis from the Late Jurassic of northeastern China.[12]
+
+Authorities disagree as to whether Salientia is a superorder that includes the order Anura, or whether Anura is a sub-order of the order Salientia. The Lissamphibia are traditionally divided into three orders, but an extinct salamander-like family, the Albanerpetontidae, is now considered part of Lissamphibia alongside the superorder Salientia. Furthermore, Salientia includes all three recent orders plus the Triassic proto-frog, Triadobatrachus.[13]
+
+The first major groups of amphibians developed in the Devonian period, around 370 million years ago, from lobe-finned fish which were similar to the modern coelacanth and lungfish.[14] These ancient lobe-finned fish had evolved multi-jointed leg-like fins with digits that enabled them to crawl along the sea bottom. Some fish had developed primitive lungs that help them breathe air when the stagnant pools of the Devonian swamps were low in oxygen. They could also use their strong fins to hoist themselves out of the water and onto dry land if circumstances so required. Eventually, their bony fins would evolve into limbs and they would become the ancestors to all tetrapods, including modern amphibians, reptiles, birds, and mammals. Despite being able to crawl on land, many of these prehistoric tetrapodomorph fish still spent most of their time in the water. They had started to develop lungs, but still breathed predominantly with gills.[15]
+
+Many examples of species showing transitional features have been discovered. Ichthyostega was one of the first primitive amphibians, with nostrils and more efficient lungs. It had four sturdy limbs, a neck, a tail with fins and a skull very similar to that of the lobe-finned fish, Eusthenopteron.[14] Amphibians evolved adaptations that allowed them to stay out of the water for longer periods. Their lungs improved and their skeletons became heavier and stronger, better able to support the weight of their bodies on land. They developed "hands" and "feet" with five or more digits;[16] the skin became more capable of retaining body fluids and resisting desiccation.[15] The fish's hyomandibula bone in the hyoid region behind the gills diminished in size and became the stapes of the amphibian ear, an adaptation necessary for hearing on dry land.[17] An affinity between the amphibians and the teleost fish is the multi-folded structure of the teeth and the paired supra-occipital bones at the back of the head, neither of these features being found elsewhere in the animal kingdom.[18]
+
+At the end of the Devonian period (360 million years ago), the seas, rivers and lakes were teeming with life while the land was the realm of early plants and devoid of vertebrates,[18] though some, such as Ichthyostega, may have sometimes hauled themselves out of the water. It is thought they may have propelled themselves with their forelimbs, dragging their hindquarters in a similar manner to that used by the elephant seal.[16] In the early Carboniferous (360 to 345 million years ago), the climate became wet and warm. Extensive swamps developed with mosses, ferns, horsetails and calamites. Air-breathing arthropods evolved and invaded the land where they provided food for the carnivorous amphibians that began to adapt to the terrestrial environment. There were no other tetrapods on the land and the amphibians were at the top of the food chain, occupying the ecological position currently held by the crocodile. Though equipped with limbs and the ability to breathe air, most still had a long tapering body and strong tail.[18] They were the top land predators, sometimes reaching several metres in length, preying on the large insects of the period and the many types of fish in the water. They still needed to return to water to lay their shell-less eggs, and even most modern amphibians have a fully aquatic larval stage with gills like their fish ancestors. It was the development of the amniotic egg, which prevents the developing embryo from drying out, that enabled the reptiles to reproduce on land and which led to their dominance in the period that followed.[14]
+
+After the Carboniferous rainforest collapse amphibian dominance gave way to reptiles,[19] and amphibians were further devastated by the Permian–Triassic extinction event.[20] During the Triassic Period (250 to 200 million years ago), the reptiles continued to out-compete the amphibians, leading to a reduction in both the amphibians' size and their importance in the biosphere. According to the fossil record, Lissamphibia, which includes all modern amphibians and is the only surviving lineage, may have branched off from the extinct groups Temnospondyli and Lepospondyli at some period between the Late Carboniferous and the Early Triassic. The relative scarcity of fossil evidence precludes precise dating,[15] but the most recent molecular study, based on multilocus sequence typing, suggests a Late Carboniferous/Early Permian origin for extant amphibians.[21]
+
+The origins and evolutionary relationships between the three main groups of amphibians is a matter of debate. A 2005 molecular phylogeny, based on rDNA analysis, suggests that salamanders and caecilians are more closely related to each other than they are to frogs. It also appears that the divergence of the three groups took place in the Paleozoic or early Mesozoic (around 250 million years ago), before the breakup of the supercontinent Pangaea and soon after their divergence from the lobe-finned fish. The briefness of this period, and the swiftness with which radiation took place, would help account for the relative scarcity of primitive amphibian fossils.[22] There are large gaps in the fossil record, but the discovery of a Gerobatrachus hottoni from the Early Permian in Texas in 2008 provided a missing link with many of the characteristics of modern frogs.[9] Molecular analysis suggests that the frog–salamander divergence took place considerably earlier than the palaeontological evidence indicates.[9] Newer research indicates that the common ancestor of all Lissamphibians lived about 315 million years ago, and that stereospondyls are the closest relatives to the caecilians.[23]
+
+As they evolved from lunged fish, amphibians had to make certain adaptations for living on land, including the need to develop new means of locomotion. In the water, the sideways thrusts of their tails had propelled them forward, but on land, quite different mechanisms were required. Their vertebral columns, limbs, limb girdles and musculature needed to be strong enough to raise them off the ground for locomotion and feeding. Terrestrial adults discarded their lateral line systems and adapted their sensory systems to receive stimuli via the medium of the air. They needed to develop new methods to regulate their body heat to cope with fluctuations in ambient temperature. They developed behaviours suitable for reproduction in a terrestrial environment. Their skins were exposed to harmful ultraviolet rays that had previously been absorbed by the water. The skin changed to become more protective and prevent excessive water loss.[24]
+
+The superclass Tetrapoda is divided into four classes of vertebrate animals with four limbs.[25] Reptiles, birds and mammals are amniotes, the eggs of which are either laid or carried by the female and are surrounded by several membranes, some of which are impervious.[26] Lacking these membranes, amphibians require water bodies for reproduction, although some species have developed various strategies for protecting or bypassing the vulnerable aquatic larval stage.[24] They are not found in the sea with the exception of one or two frogs that live in brackish water in mangrove swamps;[27] the Anderson's salamander meanwhile occurs in brackish or salt water lakes.[28] On land, amphibians are restricted to moist habitats because of the need to keep their skin damp.[24]
+
+Modern amphibians have a simplified anatomy compared to their ancestors due to paedomorphosis, caused by two evolutionary trends: miniaturization and an unusually large genome, which result in a slower growth and development rate compared to other vertebrates.[29][30] Another reason for their size is associated with their rapid metamorphosis, which seems to have evolved only in the ancestors of lissamphibia; in all other known lines the development was much more gradual. Because a remodeling of the feeding apparatus means they don't eat during the metamorphosis, the metamorphosis has to go faster the smaller the individual is, so it happens at an early stage when the larvae are still small. (The largest species of salamanders don't go through a metamorphosis.)[31] Amphibians that lay eggs on land often go through the whole metamorphosis inside the egg. An anamniotic terrestrial egg is less than 1 cm in diameter due to diffusion problems, a size which puts a limit on the amount of posthatching growth.[32]
+
+The smallest amphibian (and vertebrate) in the world is a microhylid frog from New Guinea (Paedophryne amauensis) first discovered in 2012. It has an average length of 7.7 mm (0.30 in) and is part of a genus that contains four of the world's ten smallest frog species.[33] The largest living amphibian is the 1.8 m (5 ft 11 in) Chinese giant salamander (Andrias davidianus)[34] but this is a great deal smaller than the largest amphibian that ever existed—the extinct 9 m (30 ft) Prionosuchus, a crocodile-like temnospondyl dating to 270 million years ago from the middle Permian of Brazil.[35] The largest frog is the African Goliath frog (Conraua goliath), which can reach 32 cm (13 in) and weigh 3 kg (6.6 lb).[34]
+
+Amphibians are ectothermic (cold-blooded) vertebrates that do not maintain their body temperature through internal physiological processes. Their metabolic rate is low and as a result, their food and energy requirements are limited. In the adult state, they have tear ducts and movable eyelids, and most species have ears that can detect airborne or ground vibrations. They have muscular tongues, which in many species can be protruded. Modern amphibians have fully ossified vertebrae with articular processes. Their ribs are usually short and may be fused to the vertebrae. Their skulls are mostly broad and short, and are often incompletely ossified. Their skin contains little keratin and lacks scales, apart from a few fish-like scales in certain caecilians. The skin contains many mucous glands and in some species, poison glands (a type of granular gland). The hearts of amphibians have three chambers, two atria and one ventricle. They have a urinary bladder and nitrogenous waste products are excreted primarily as urea. Most amphibians lay their eggs in water and have aquatic larvae that undergo metamorphosis to become terrestrial adults. Amphibians breathe by means of a pump action in which air is first drawn into the buccopharyngeal region through the nostrils. These are then closed and the air is forced into the lungs by contraction of the throat.[36] They supplement this with gas exchange through the skin.[24]
+
+The order Anura (from the Ancient Greek a(n)- meaning "without" and oura meaning "tail") comprises the frogs and toads. They usually have long hind limbs that fold underneath them, shorter forelimbs, webbed toes with no claws, no tails, large eyes and glandular moist skin.[8] Members of this order with smooth skins are commonly referred to as frogs, while those with warty skins are known as toads. The difference is not a formal one taxonomically and there are numerous exceptions to this rule. Members of the family Bufonidae are known as the "true toads".[37] Frogs range in size from the 30-centimetre (12 in) Goliath frog (Conraua goliath) of West Africa[38] to the 7.7-millimetre (0.30 in) Paedophryne amauensis, first described in Papua New Guinea in 2012, which is also the smallest known vertebrate.[39] Although most species are associated with water and damp habitats, some are specialised to live in trees or in deserts. They are found worldwide except for polar areas.[40]
+
+Anura is divided into three suborders that are broadly accepted by the scientific community, but the relationships between some families remain unclear. Future molecular studies should provide further insights into their evolutionary relationships.[41] The suborder Archaeobatrachia contains four families of primitive frogs. These are Ascaphidae, Bombinatoridae, Discoglossidae and Leiopelmatidae which have few derived features and are probably paraphyletic with regard to other frog lineages.[42] The six families in the more evolutionarily advanced suborder Mesobatrachia are the fossorial Megophryidae, Pelobatidae, Pelodytidae, Scaphiopodidae and Rhinophrynidae and the obligatorily aquatic Pipidae. These have certain characteristics that are intermediate between the two other suborders.[42] Neobatrachia is by far the largest suborder and includes the remaining families of modern frogs, including most common species. Ninety-six percent of the over 5,000 extant species of frog are neobatrachians.[43]
+
+The order Caudata (from the Latin cauda meaning "tail") consists of the salamanders—elongated, low-slung animals that mostly resemble lizards in form. This is a symplesiomorphic trait and they are no more closely related to lizards than they are to mammals.[44] Salamanders lack claws, have scale-free skins, either smooth or covered with tubercles, and tails that are usually flattened from side to side and often finned. They range in size from the Chinese giant salamander (Andrias davidianus), which has been reported to grow to a length of 1.8 metres (5 ft 11 in),[45] to the diminutive Thorius pennatulus from Mexico which seldom exceeds 20 mm (0.8 in) in length.[46] Salamanders have a mostly Laurasian distribution, being present in much of the Holarctic region of the northern hemisphere. The family Plethodontidae is also found in Central America and South America north of the Amazon basin;[40] South America was apparently invaded from Central America by about the start of the Miocene, 23 million years ago.[47] Urodela is a name sometimes used for all the extant species of salamanders.[48] Members of several salamander families have become paedomorphic and either fail to complete their metamorphosis or retain some larval characteristics as adults.[49] Most salamanders are under 15 cm (6 in) long. They may be terrestrial or aquatic and many spend part of the year in each habitat. When on land, they mostly spend the day hidden under stones or logs or in dense vegetation, emerging in the evening and night to forage for worms, insects and other invertebrates.[40]
+
+The suborder Cryptobranchoidea contains the primitive salamanders. A number of fossil cryptobranchids have been found, but there are only three living species, the Chinese giant salamander (Andrias davidianus), the Japanese giant salamander (Andrias japonicus) and the hellbender (Cryptobranchus alleganiensis) from North America. These large amphibians retain several larval characteristics in their adult state; gills slits are present and the eyes are unlidded. A unique feature is their ability to feed by suction, depressing either the left side of their lower jaw or the right.[50] The males excavate nests, persuade females to lay their egg strings inside them, and guard them. As well as breathing with lungs, they respire through the many folds in their thin skin, which has capillaries close to the surface.[51]
+
+The suborder Salamandroidea contains the advanced salamanders. They differ from the cryptobranchids by having fused prearticular bones in the lower jaw, and by using internal fertilisation. In salamandrids, the male deposits a bundle of sperm, the spermatophore, and the female picks it up and inserts it into her cloaca where the sperm is stored until the eggs are laid.[52] The largest family in this group is Plethodontidae, the lungless salamanders, which includes 60% of all salamander species. The family Salamandridae includes the true salamanders and the name "newt" is given to members of its subfamily Pleurodelinae.[8]
+
+The third suborder, Sirenoidea, contains the four species of sirens, which are in a single family, Sirenidae. Members of this order are eel-like aquatic salamanders with much reduced forelimbs and no hind limbs. Some of their features are primitive while others are derived.[53] Fertilisation is likely to be external as sirenids lack the cloacal glands used by male salamandrids to produce spermatophores and the females lack spermathecae for sperm storage. Despite this, the eggs are laid singly, a behaviour not conducive for external fertilisation.[52]
+
+The order Gymnophiona (from the Greek gymnos meaning "naked" and ophis meaning "serpent") or Apoda comprises the caecilians. These are long, cylindrical, limbless animals with a snake- or worm-like form. The adults vary in length from 8 to 75 centimetres (3 to 30 inches) with the exception of Thomson's caecilian (Caecilia thompsoni), which can reach 150 centimetres (4.9 feet). A caecilian's skin has a large number of transverse folds and in some species contains tiny embedded dermal scales. It has rudimentary eyes covered in skin, which are probably limited to discerning differences in light intensity. It also has a pair of short tentacles near the eye that can be extended and which have tactile and olfactory functions. Most caecilians live underground in burrows in damp soil, in rotten wood and under plant debris, but some are aquatic.[54] Most species lay their eggs underground and when the larvae hatch, they make their way to adjacent bodies of water. Others brood their eggs and the larvae undergo metamorphosis before the eggs hatch. A few species give birth to live young, nourishing them with glandular secretions while they are in the oviduct.[55] Caecilians have a mostly Gondwanan distribution, being found in tropical regions of Africa, Asia and Central and South America.[56]
+
+The integumentary structure contains some typical characteristics common to terrestrial vertebrates, such as the presence of highly cornified outer layers, renewed periodically through a moulting process controlled by the pituitary and thyroid glands. Local thickenings (often called warts) are common, such as those found on toads. The outside of the skin is shed periodically mostly in one piece, in contrast to mammals and birds where it is shed in flakes. Amphibians often eat the sloughed skin.[40] Caecilians are unique among amphibians in having mineralized dermal scales embedded in the dermis between the furrows in the skin. The similarity of these to the scales of bony fish is largely superficial. Lizards and some frogs have somewhat similar osteoderms forming bony deposits in the dermis, but this is an example of convergent evolution with similar structures having arisen independently in diverse vertebrate lineages.[57]
+
+Amphibian skin is permeable to water. Gas exchange can take place through the skin (cutaneous respiration) and this allows adult amphibians to respire without rising to the surface of water and to hibernate at the bottom of ponds.[40] To compensate for their thin and delicate skin, amphibians have evolved mucous glands, principally on their heads, backs and tails. The secretions produced by these help keep the skin moist. In addition, most species of amphibian have granular glands that secrete distasteful or poisonous substances. Some amphibian toxins can be lethal to humans while others have little effect.[58] The main poison-producing glands, the parotoids, produce the neurotoxin bufotoxin and are located behind the ears of toads, along the backs of frogs, behind the eyes of salamanders and on the upper surface of caecilians.[59]
+
+The skin colour of amphibians is produced by three layers of pigment cells called chromatophores. These three cell layers consist of the melanophores (occupying the deepest layer), the guanophores (forming an intermediate layer and containing many granules, producing a blue-green colour) and the lipophores (yellow, the most superficial layer). The colour change displayed by many species is initiated by hormones secreted by the pituitary gland. Unlike bony fish, there is no direct control of the pigment cells by the nervous system, and this results in the colour change taking place more slowly than happens in fish. A vividly coloured skin usually indicates that the species is toxic and is a warning sign to predators.[60]
+
+Amphibians have a skeletal system that is structurally homologous to other tetrapods, though with a number of variations. They all have four limbs except for the legless caecilians and a few species of salamander with reduced or no limbs. The bones are hollow and lightweight. The musculoskeletal system is strong to enable it to support the head and body. The bones are fully ossified and the vertebrae interlock with each other by means of overlapping processes. The pectoral girdle is supported by muscle, and the well-developed pelvic girdle is attached to the backbone by a pair of sacral ribs. The ilium slopes forward and the body is held closer to the ground than is the case in mammals.[61]
+
+In most amphibians, there are four digits on the fore foot and five on the hind foot, but no claws on either. Some salamanders have fewer digits and the amphiumas are eel-like in appearance with tiny, stubby legs. The sirens are aquatic salamanders with stumpy forelimbs and no hind limbs. The caecilians are limbless. They burrow in the manner of earthworms with zones of muscle contractions moving along the body. On the surface of the ground or in water they move by undulating their body from side to side.[62]
+
+In frogs, the hind legs are larger than the fore legs, especially so in those species that principally move by jumping or swimming. In the walkers and runners the hind limbs are not so large, and the burrowers mostly have short limbs and broad bodies. The feet have adaptations for the way of life, with webbing between the toes for swimming, broad adhesive toe pads for climbing, and keratinised tubercles on the hind feet for digging (frogs usually dig backwards into the soil). In most salamanders, the limbs are short and more or less the same length and project at right angles from the body. Locomotion on land is by walking and the tail often swings from side to side or is used as a prop, particularly when climbing. In their normal gait, only one leg is advanced at a time in the manner adopted by their ancestors, the lobe-finned fish.[61] Some salamanders in the genus Aneides and certain plethodontids climb trees and have long limbs, large toepads and prehensile tails.[52] In aquatic salamanders and in frog tadpoles, the tail has dorsal and ventral fins and is moved from side to side as a means of propulsion. Adult frogs do not have tails and caecilians have only very short ones.[62]
+
+Salamanders use their tails in defence and some are prepared to jettison them to save their lives in a process known as autotomy. Certain species in the Plethodontidae have a weak zone at the base of the tail and use this strategy readily. The tail often continues to twitch after separation which may distract the attacker and allow the salamander to escape. Both tails and limbs can be regenerated.[63] Adult frogs are unable to regrow limbs but tadpoles can do so.[62]
+
+Amphibians have a juvenile stage and an adult stage, and the circulatory systems of the two are distinct. In the juvenile (or tadpole) stage, the circulation is similar to that of a fish; the two-chambered heart pumps the blood through the gills where it is oxygenated, and is spread around the body and back to the heart in a single loop. In the adult stage, amphibians (especially frogs) lose their gills and develop lungs. They have a heart that consists of a single ventricle and two atria. When the ventricle starts contracting, deoxygenated blood is pumped through the pulmonary artery to the lungs. Continued contraction then pumps oxygenated blood around the rest of the body. Mixing of the two bloodstreams is minimized by the anatomy of the chambers.[64]
+
+The nervous system is basically the same as in other vertebrates, with a central brain, a spinal cord, and nerves throughout the body. The amphibian brain is less well developed than that of reptiles, birds and mammals but is similar in morphology and function to that of a fish. It is believed amphibians are capable of perceiving pain.  The brain consists of equal parts, cerebrum, midbrain and cerebellum. Various parts of the cerebrum process sensory input, such as smell in the olfactory lobe and sight in the optic lobe, and it is additionally the centre of behaviour and learning. The cerebellum is the center of muscular coordination and the medulla oblongata controls some organ functions including heartbeat and respiration. The brain sends signals through the spinal cord and nerves to regulate activity in the rest of the body. The pineal body, known to regulate sleep patterns in humans, is thought to produce the hormones involved in hibernation and aestivation in amphibians.[65]
+
+Tadpoles retain the lateral line system of their ancestral fishes, but this is lost in terrestrial adult amphibians. Some caecilians possess electroreceptors that allow them to locate objects around them when submerged in water. The ears are well developed in frogs. There is no external ear, but the large circular eardrum lies on the surface of the head just behind the eye. This vibrates and sound is transmitted through a single bone, the stapes, to the inner ear. Only high-frequency sounds like mating calls are heard in this way, but low-frequency noises can be detected through another mechanism.[61] There is a patch of specialized haircells, called papilla amphibiorum, in the inner ear capable of detecting deeper sounds. Another feature, unique to frogs and salamanders, is the columella-operculum complex adjoining the auditory capsule which is involved in the transmission of both airborne and seismic signals.[66] The ears of salamanders and caecilians are less highly developed than those of frogs as they do not normally communicate with each other through the medium of sound.[67]
+
+The eyes of tadpoles lack lids, but at metamorphosis, the cornea becomes more dome-shaped, the lens becomes flatter, and eyelids and associated glands and ducts develop.[61] The adult eyes are an improvement on invertebrate eyes and were a first step in the development of more advanced vertebrate eyes. They allow colour vision and depth of focus. In the retinas are green rods, which are receptive to a wide range of wavelengths.[67]
+
+Many amphibians catch their prey by flicking out an elongated tongue with a sticky tip and drawing it back into the mouth before seizing the item with their jaws. Some use inertial feeding to help them swallow the prey, repeatedly thrusting their head forward sharply causing the food to move backwards in their mouth by inertia. Most amphibians swallow their prey whole without much chewing so they possess voluminous stomachs. The short oesophagus is lined with cilia that help to move the food to the stomach and mucus produced by glands in the mouth and pharynx eases its passage. The enzyme chitinase produced in the stomach helps digest the chitinous cuticle of arthropod prey.[68]
+
+Amphibians possess a pancreas, liver and gall bladder. The liver is usually large with two lobes. Its size is determined by its function as a glycogen and fat storage unit, and may change with the seasons as these reserves are built or used up. Adipose tissue is another important means of storing energy and this occurs in the abdomen (in internal structures called fat bodies), under the skin and, in some salamanders, in the tail.[69]
+
+There are two kidneys located dorsally, near the roof of the body cavity. Their job is to filter the blood of metabolic waste and transport the urine via ureters to the urinary bladder where it is stored before being passed out periodically through the cloacal vent. Larvae and most aquatic adult amphibians excrete the nitrogen as ammonia in large quantities of dilute urine, while terrestrial species, with a greater need to conserve water, excrete the less toxic product urea. Some tree frogs with limited access to water excrete most of their metabolic waste as uric acid.[70]
+
+The lungs in amphibians are primitive compared to those of amniotes, possessing few internal septa and large alveoli, and consequently having a comparatively slow diffusion rate for oxygen entering the blood. Ventilation is accomplished by buccal pumping.[71] Most amphibians, however, are able to exchange gases with the water or air via their skin. To enable sufficient cutaneous respiration, the surface of their highly vascularised skin must remain moist to allow the oxygen to diffuse at a sufficiently high rate.[68] Because oxygen concentration in the water increases at both low temperatures and high flow rates, aquatic amphibians in these situations can rely primarily on cutaneous respiration, as in the Titicaca water frog and the hellbender salamander. In air, where oxygen is more concentrated, some small species can rely solely on cutaneous gas exchange, most famously the plethodontid salamanders, which have neither lungs nor gills. Many aquatic salamanders and all tadpoles have gills in their larval stage, with some (such as the axolotl) retaining gills as aquatic adults.[68]
+
+For the purpose of reproduction most amphibians require fresh water although some lay their eggs on land and have developed various means of keeping them moist. A few (e.g. Fejervarya raja) can inhabit brackish water, but there are no true marine amphibians.[72] There are reports, however, of particular amphibian populations unexpectedly invading marine waters. Such was the case with the Black Sea invasion of the natural hybrid Pelophylax esculentus reported in 2010.[73]
+
+Several hundred frog species in adaptive radiations (e.g., Eleutherodactylus, the Pacific Platymantis, the Australo-Papuan microhylids, and many other tropical frogs), however, do not need any water for breeding in the wild. They reproduce via direct development, an ecological and evolutionary adaptation that has allowed them to be completely independent from free-standing water. Almost all of these frogs live in wet tropical rainforests and their eggs hatch directly into miniature versions of the adult, passing through the tadpole stage within the egg. Reproductive success of many amphibians is dependent not only on the quantity of rainfall, but the seasonal timing.[74]
+
+In the tropics, many amphibians breed continuously or at any time of year. In temperate regions, breeding is mostly seasonal, usually in the spring, and is triggered by increasing day length, rising temperatures or rainfall. Experiments have shown the importance of temperature, but the trigger event, especially in arid regions, is often a storm. In anurans, males usually arrive at the breeding sites before females and the vocal chorus they produce may stimulate ovulation in females and the endocrine activity of males that are not yet reproductively active.[75]
+
+In caecilians, fertilisation is internal, the male extruding an intromittent organ, the phallodeum, and inserting it into the female cloaca. The paired Müllerian glands inside the male cloaca secrete a fluid which resembles that produced by mammalian prostate glands and which may transport and nourish the sperm. Fertilisation probably takes place in the oviduct.[76]
+
+The majority of salamanders also engage in internal fertilisation. In most of these, the male deposits a spermatophore, a small packet of sperm on top of a gelatinous cone, on the substrate either on land or in the water. The female takes up the sperm packet by grasping it with the lips of the cloaca and pushing it into the vent. The spermatozoa move to the spermatheca in the roof of the cloaca where they remain until ovulation which may be many months later. Courtship rituals and methods of transfer of the spermatophore vary between species. In some, the spermatophore may be placed directly into the female cloaca while in others, the female may be guided to the spermatophore or restrained with an embrace called amplexus. Certain primitive salamanders in the families Sirenidae, Hynobiidae and Cryptobranchidae practice external fertilisation in a similar manner to frogs, with the female laying the eggs in water and the male releasing sperm onto the egg mass.[76]
+
+With a few exceptions, frogs use external fertilisation. The male grasps the female tightly with his forelimbs either behind the arms or in front of the back legs, or in the case of Epipedobates tricolor, around the neck. They remain in amplexus with their cloacae positioned close together while the female lays the eggs and the male covers them with sperm. Roughened nuptial pads on the male's hands aid in retaining grip. Often the male collects and retains the egg mass, forming a sort of basket with the hind feet. An exception is the granular poison frog (Oophaga granulifera) where the male and female place their cloacae in close proximity while facing in opposite directions and then release eggs and sperm simultaneously. The tailed frog (Ascaphus truei) exhibits internal fertilisation. The "tail" is only possessed by the male and is an extension of the cloaca and used to inseminate the female. This frog lives in fast-flowing streams and internal fertilisation prevents the sperm from being washed away before fertilisation occurs.[77] The sperm may be retained in storage tubes attached to the oviduct until the following spring.[78]
+
+Most frogs can be classified as either prolonged or explosive breeders. Typically, prolonged breeders congregate at a breeding site, the males usually arriving first, calling and setting up territories. Other satellite males remain quietly nearby, waiting for their opportunity to take over a territory. The females arrive sporadically, mate selection takes place and eggs are laid. The females depart and territories may change hands. More females appear and in due course, the breeding season comes to an end. Explosive breeders on the other hand are found where temporary pools appear in dry regions after rainfall. These frogs are typically fossorial species that emerge after heavy rains and congregate at a breeding site. They are attracted there by the calling of the first male to find a suitable place, perhaps a pool that forms in the same place each rainy season. The assembled frogs may call in unison and frenzied activity ensues, the males scrambling to mate with the usually smaller number of females.[77]
+
+There is a direct competition between males to win the attention of the females in salamanders and newts, with elaborate courtship displays to keep the female's attention long enough to get her interested in choosing him to mate with.[79] Some species store sperm through long breeding seasons, as the extra time may allow for interactions with rival sperm.[80]
+
+Most amphibians go through metamorphosis, a process of significant morphological change after birth. In typical amphibian development, eggs are laid in water and larvae are adapted to an aquatic lifestyle. Frogs, toads and salamanders all hatch from the egg as larvae with external gills. Metamorphosis in amphibians is regulated by thyroxine concentration in the blood, which stimulates metamorphosis, and prolactin, which counteracts thyroxine's effect. Specific events are dependent on threshold values for different tissues.[81] Because most embryonic development is outside the parental body, it is subject to many adaptations due to specific environmental circumstances. For this reason tadpoles can have horny ridges instead of teeth, whisker-like skin extensions or fins. They also make use of a sensory lateral line organ similar to that of fish. After metamorphosis, these organs become redundant and will be reabsorbed by controlled cell death, called apoptosis. The variety of adaptations to specific environmental circumstances among amphibians is wide, with many discoveries still being made.[82]
+
+The egg of an amphibian is typically surrounded by a transparent gelatinous covering secreted by the oviducts and containing mucoproteins and mucopolysaccharides. This capsule is permeable to water and gases, and swells considerably as it absorbs water. The ovum is at first rigidly held, but in fertilised eggs the innermost layer liquefies and allows the embryo to move freely. This also happens in salamander eggs, even when they are unfertilised. Eggs of some salamanders and frogs contain unicellular green algae. These penetrate the jelly envelope after the eggs are laid and may increase the supply of oxygen to the embryo through photosynthesis. They seem to both speed up the development of the larvae and reduce mortality.[83] Most eggs contain the pigment melanin which raises their temperature through the absorption of light and also protects them against ultraviolet radiation. Caecilians, some plethodontid salamanders and certain frogs lay eggs underground that are unpigmented. In the wood frog (Rana sylvatica), the interior of the globular egg cluster has been found to be up to 6 °C (11 °F) warmer than its surroundings, which is an advantage in its cool northern habitat.[84]
+
+The eggs may be deposited singly or in small groups, or may take the form of spherical egg masses, rafts or long strings. In terrestrial caecilians, the eggs are laid in grape-like clusters in burrows near streams. The amphibious salamander Ensatina attaches its similar clusters by stalks to underwater stems and roots. The greenhouse frog (Eleutherodactylus planirostris) lays eggs in small groups in the soil where they develop in about two weeks directly into juvenile frogs without an intervening larval stage.[85] The tungara frog (Physalaemus pustulosus) builds a floating nest from foam to protect its eggs. First a raft is built, then eggs are laid in the centre, and finally a foam cap is overlaid. The foam has anti-microbial properties. It contains no detergents but is created by whipping up proteins and lectins secreted by the female.[86][87]
+
+The eggs of amphibians are typically laid in water and hatch into free-living larvae that complete their development in water and later transform into either aquatic or terrestrial adults. In many species of frog and in most lungless salamanders (Plethodontidae), direct development takes place, the larvae growing within the eggs and emerging as miniature adults. Many caecilians and some other amphibians lay their eggs on land, and the newly hatched larvae wriggle or are transported to water bodies. Some caecilians, the alpine salamander (Salamandra atra) and some of the African live-bearing toads (Nectophrynoides spp.) are viviparous. Their larvae feed on glandular secretions and develop within the female's oviduct, often for long periods. Other amphibians, but not caecilians, are ovoviviparous. The eggs are retained in or on the parent's body, but the larvae subsist on the yolks of their eggs and receive no nourishment from the adult. The larvae emerge at varying stages of their growth, either before or after metamorphosis, according to their species.[88] The toad genus Nectophrynoides exhibits all of these developmental patterns among its dozen or so members.[6]
+
+Frog larvae are known as tadpoles and typically have oval bodies and long, vertically flattened tails with fins. The free-living larvae are normally fully aquatic, but the tadpoles of some species (such as Nannophrys ceylonensis) are semi-terrestrial and live among wet rocks.[89] Tadpoles have cartilaginous skeletons, gills for respiration (external gills at first, internal gills later), lateral line systems and large tails that they use for swimming.[90] Newly hatched tadpoles soon develop gill pouches that cover the gills. The lungs develop early and are used as accessory breathing organs, the tadpoles rising to the water surface to gulp air. Some species complete their development inside the egg and hatch directly into small frogs. These larvae do not have gills but instead have specialised areas of skin through which respiration takes place. While tadpoles do not have true teeth, in most species, the jaws have long, parallel rows of small keratinized structures called keradonts surrounded by a horny beak.[91] Front legs are formed under the gill sac and hind legs become visible a few days later.
+
+Iodine and T4 (over stimulate the spectacular apoptosis [programmed cell death] of the cells of the larval gills, tail and fins) also stimulate the evolution of nervous systems transforming the aquatic, vegetarian tadpole into the terrestrial, carnivorous frog with better neurological, visuospatial, olfactory and cognitive abilities for hunting.[92][93]
+
+In fact, tadpoles developing in ponds and streams are typically herbivorous. Pond tadpoles tend to have deep bodies, large caudal fins and small mouths; they swim in the quiet waters feeding on growing or loose fragments of vegetation. Stream dwellers mostly have larger mouths, shallow bodies and caudal fins; they attach themselves to plants and stones and feed on the surface films of algae and bacteria.[94] They also feed on diatoms, filtered from the water through the gills, and stir up the sediment at bottom of the pond, ingesting edible fragments. They have a relatively long, spiral-shaped gut to enable them to digest this diet.[94] Some species are carnivorous at the tadpole stage, eating insects, smaller tadpoles and fish. Young of the Cuban tree frog (Osteopilus septentrionalis) can occasionally be cannibalistic, the younger tadpoles attacking a larger, more developed tadpole when it is undergoing metamorphosis.[95]
+
+At metamorphosis, rapid changes in the body take place as the lifestyle of the frog changes completely. The spiral‐shaped mouth with horny tooth ridges is reabsorbed together with the spiral gut. The animal develops a large jaw, and its gills disappear along with its gill sac. Eyes and legs grow quickly, and a tongue is formed. There are associated changes in the neural networks such as development of stereoscopic vision and loss of the lateral line system. All this can happen in about a day. A few days later, the tail is reabsorbed, due to the higher thyroxine concentration required for this to take place.[94]
+
+At hatching, a typical salamander larva has eyes without lids, teeth in both upper and lower jaws, three pairs of feathery external gills, a somewhat laterally flattened body and a long tail with dorsal and ventral fins. The forelimbs may be partially developed and the hind limbs are rudimentary in pond-living species but may be rather more developed in species that reproduce in moving water. Pond-type larvae often have a pair of balancers, rod-like structures on either side of the head that may prevent the gills from becoming clogged up with sediment. Some members of the genera Ambystoma and Dicamptodon have larvae that never fully develop into the adult form, but this varies with species and with populations. The northwestern salamander (Ambystoma gracile) is one of these and, depending on environmental factors, either remains permanently in the larval state, a condition known as neoteny, or transforms into an adult.[96] Both of these are able to breed.[97] Neoteny occurs when the animal's growth rate is very low and is usually linked to adverse conditions such as low water temperatures that may change the response of the tissues to the hormone thyroxine.[98] Other factors that may inhibit metamorphosis include lack of food, lack of trace elements and competition from conspecifics. The tiger salamander (Ambystoma tigrinum) also sometimes behaves in this way and may grow particularly large in the process. The adult tiger salamander is terrestrial, but the larva is aquatic and able to breed while still in the larval state. When conditions are particularly inhospitable on land, larval breeding may allow continuation of a population that would otherwise die out. There are fifteen species of obligate neotenic salamanders, including species of Necturus, Proteus and Amphiuma, and many examples of facultative ones that adopt this strategy under appropriate environmental circumstances.[99]
+
+Lungless salamanders in the family Plethodontidae are terrestrial and lay a small number of unpigmented eggs in a cluster among damp leaf litter. Each egg has a large yolk sac and the larva feeds on this while it develops inside the egg, emerging fully formed as a juvenile salamander. The female salamander often broods the eggs. In the genus Ensatinas, the female has been observed to coil around them and press her throat area against them, effectively massaging them with a mucous secretion.[100]
+
+In newts and salamanders, metamorphosis is less dramatic than in frogs. This is because the larvae are already carnivorous and continue to feed as predators when they are adults so few changes are needed to their digestive systems. Their lungs are functional early, but the larvae do not make as much use of them as do tadpoles. Their gills are never covered by gill sacs and are reabsorbed just before the animals leave the water. Other changes include the reduction in size or loss of tail fins, the closure of gill slits, thickening of the skin, the development of eyelids, and certain changes in dentition and tongue structure. Salamanders are at their most vulnerable at metamorphosis as swimming speeds are reduced and transforming tails are encumbrances on land.[101] Adult salamanders often have an aquatic phase in spring and summer, and a land phase in winter. For adaptation to a water phase, prolactin is the required hormone, and for adaptation to the land phase, thyroxine. External gills do not return in subsequent aquatic phases because these are completely absorbed upon leaving the water for the first time.[102]
+
+Most terrestrial caecilians that lay eggs do so in burrows or moist places on land near bodies of water. The development of the young of Ichthyophis glutinosus, a species from Sri Lanka, has been much studied. The eel-like larvae hatch out of the eggs and make their way to water. They have three pairs of external red feathery gills, a blunt head with two rudimentary eyes, a lateral line system and a short tail with fins. They swim by undulating their body from side to side. They are mostly active at night, soon lose their gills and make sorties onto land. Metamorphosis is gradual. By the age of about ten months they have developed a pointed head with sensory tentacles near the mouth and lost their eyes, lateral line systems and tails. The skin thickens, embedded scales develop and the body divides into segments. By this time, the caecilian has constructed a burrow and is living on land.[103]
+
+In the majority of species of caecilians, the young are produced by viviparity. Typhlonectes compressicauda, a species from South America, is typical of these. Up to nine larvae can develop in the oviduct at any one time. They are elongated and have paired sac-like gills, small eyes and specialised scraping teeth. At first, they feed on the yolks of the eggs, but as this source of nourishment declines they begin to rasp at the ciliated epithelial cells that line the oviduct. This stimulates the secretion of fluids rich in lipids and mucoproteins on which they feed along with scrapings from the oviduct wall. They may increase their length sixfold and be two-fifths as long as their mother before being born. By this time they have undergone metamorphosis, lost their eyes and gills, developed a thicker skin and mouth tentacles, and reabsorbed their teeth. A permanent set of teeth grow through soon after birth.[104][105]
+
+The ringed caecilian (Siphonops annulatus) has developed a unique adaptation for the purposes of reproduction. The progeny feed on a skin layer that is specially developed by the adult in a phenomenon known as maternal dermatophagy. The brood feed as a batch for about seven minutes at intervals of approximately three days which gives the skin an opportunity to regenerate. Meanwhile, they have been observed to ingest fluid exuded from the maternal cloaca.[106]
+
+The care of offspring among amphibians has been little studied but, in general, the larger the number of eggs in a batch, the less likely it is that any degree of parental care takes place. Nevertheless, it is estimated that in up to 20% of amphibian species, one or both adults play some role in the care of the young.[107] Those species that breed in smaller water bodies or other specialised habitats tend to have complex patterns of behaviour in the care of their young.[108]
+
+Many woodland salamanders lay clutches of eggs under dead logs or stones on land. The black mountain salamander (Desmognathus welteri) does this, the mother brooding the eggs and guarding them from predation as the embryos feed on the yolks of their eggs. When fully developed, they break their way out of the egg capsules and disperse as juvenile salamanders.[109] The male hellbender, a primitive salamander, excavates an underwater nest and encourages females to lay there. The male then guards the site for the two or three months before the eggs hatch, using body undulations to fan the eggs and increase their supply of oxygen.[51]
+
+The male Colostethus subpunctatus, a tiny frog, protects the egg cluster which is hidden under a stone or log. When the eggs hatch, the male transports the tadpoles on his back, stuck there by a mucous secretion, to a temporary pool where he dips himself into the water and the tadpoles drop off.[110] The male midwife toad (Alytes obstetricans) winds egg strings round his thighs and carries the eggs around for up to eight weeks. He keeps them moist and when they are ready to hatch, he visits a pond or ditch and releases the tadpoles.[111] The female gastric-brooding frog (Rheobatrachus spp.) reared larvae in her stomach after swallowing either the eggs or hatchlings; however, this stage was never observed before the species became extinct. The tadpoles secrete a hormone that inhibits digestion in the mother whilst they develop by consuming their very large yolk supply.[112] The pouched frog (Assa darlingtoni) lays eggs on the ground. When they hatch, the male carries the tadpoles around in brood pouches on his hind legs.[113] The aquatic Surinam toad (Pipa pipa) raises its young in pores on its back where they remain until metamorphosis.[114] The granular poison frog (Oophaga granulifera) is typical of a number of tree frogs in the poison dart frog family Dendrobatidae. Its eggs are laid on the forest floor and when they hatch, the tadpoles are carried one by one on the back of an adult to a suitable water-filled crevice such as the axil of a leaf or the rosette of a bromeliad. The female visits the nursery sites regularly and deposits unfertilised eggs in the water and these are consumed by the tadpoles.[115]
+
+With a few exceptions, adult amphibians are predators, feeding on virtually anything that moves that they can swallow. The diet mostly consists of small prey that do not move too fast such as beetles, caterpillars, earthworms and spiders. The sirens (Siren spp.) often ingest aquatic plant material with the invertebrates on which they feed[116] and a Brazilian tree frog (Xenohyla truncata) includes a large quantity of fruit in its diet.[117] The Mexican burrowing toad (Rhinophrynus dorsalis) has a specially adapted tongue for picking up ants and termites. It projects it with the tip foremost whereas other frogs flick out the rear part first, their tongues being hinged at the front.[118]
+
+Food is mostly selected by sight, even in conditions of dim light. Movement of the prey triggers a feeding response. Frogs have been caught on fish hooks baited with red flannel and green frogs (Rana clamitans) have been found with stomachs full of elm seeds that they had seen floating past.[119] Toads, salamanders and caecilians also use smell to detect prey. This response is mostly secondary because salamanders have been observed to remain stationary near odoriferous prey but only feed if it moves. Cave-dwelling amphibians normally hunt by smell. Some salamanders seem to have learned to recognize immobile prey when it has no smell, even in complete darkness.[120]
+
+Amphibians usually swallow food whole but may chew it lightly first to subdue it.[40] They typically have small hinged pedicellate teeth, a feature unique to amphibians. The base and crown of these are composed of dentine separated by an uncalcified layer and they are replaced at intervals. Salamanders, caecilians and some frogs have one or two rows of teeth in both jaws, but some frogs (Rana spp.) lack teeth in the lower jaw, and toads (Bufo spp.) have no teeth. In many amphibians there are also vomerine teeth attached to a facial bone in the roof of the mouth.[121]
+
+The tiger salamander (Ambystoma tigrinum) is typical of the frogs and salamanders that hide under cover ready to ambush unwary invertebrates. Others amphibians, such as the Bufo spp. toads, actively search for prey, while the Argentine horned frog (Ceratophrys ornata) lures inquisitive prey closer by raising its hind feet over its back and vibrating its yellow toes.[122] Among leaf litter frogs in Panama, frogs that actively hunt prey have narrow mouths and are slim, often brightly coloured and toxic, while ambushers have wide mouths and are broad and well-camouflaged.[123] Caecilians do not flick their tongues, but catch their prey by grabbing it with their slightly backward-pointing teeth. The struggles of the prey and further jaw movements work it inwards and the caecilian usually retreats into its burrow. The subdued prey is gulped down whole.[124]
+
+When they are newly hatched, frog larvae feed on the yolk of the egg. When this is exhausted some move on to feed on bacteria, algal crusts, detritus and raspings from submerged plants. Water is drawn in through their mouths, which are usually at the bottom of their heads, and passes through branchial food traps between their mouths and their gills where fine particles are trapped in mucus and filtered out. Others have specialised mouthparts consisting of a horny beak edged by several rows of labial teeth. They scrape and bite food of many kinds as well as stirring up the bottom sediment, filtering out larger particles with the papillae around their mouths. Some, such as the spadefoot toads, have strong biting jaws and are carnivorous or even cannibalistic.[125]
+
+The calls made by caecilians and salamanders are limited to occasional soft squeaks, grunts or hisses and have not been much studied. A clicking sound sometimes produced by caecilians may be a means of orientation, as in bats, or a form of communication. Most salamanders are considered voiceless, but the California giant salamander (Dicamptodon ensatus) has vocal cords and can produce a rattling or barking sound. Some species of salamander emit a quiet squeak or yelp if attacked.[126]
+
+Frogs are much more vocal, especially during the breeding season when they use their voices to attract mates. The presence of a particular species in an area may be more easily discerned by its characteristic call than by a fleeting glimpse of the animal itself. In most species, the sound is produced by expelling air from the lungs over the vocal cords into an air sac or sacs in the throat or at the corner of the mouth. This may distend like a balloon and acts as a resonator, helping to transfer the sound to the atmosphere, or the water at times when the animal is submerged.[126] The main vocalisation is the male's loud advertisement call which seeks to both encourage a female to approach and discourage other males from intruding on its territory. This call is modified to a quieter courtship call on the approach of a female or to a more aggressive version if a male intruder draws near. Calling carries the risk of attracting predators and involves the expenditure of much energy.[127] Other calls include those given by a female in response to the advertisement call and a release call given by a male or female during unwanted attempts at amplexus. When a frog is attacked, a distress or fright call is emitted, often resembling a scream.[128] The usually nocturnal Cuban tree frog (Osteopilus septentrionalis) produces a rain call when there is rainfall during daylight hours.[129]
+
+Little is known of the territorial behaviour of caecilians, but some frogs and salamanders defend home ranges. These are usually feeding, breeding or sheltering sites. Males normally exhibit such behaviour though in some species, females and even juveniles are also involved. Although in many frog species, females are larger than males, this is not the case in most species where males are actively involved in territorial defence. Some of these have specific adaptations such as enlarged teeth for biting or spines on the chest, arms or thumbs.[130]
+
+In salamanders, defence of a territory involves adopting an aggressive posture and if necessary attacking the intruder. This may involve snapping, chasing and sometimes biting, occasionally causing the loss of a tail. The behaviour of red back salamanders (Plethodon cinereus) has been much studied. 91% of marked individuals that were later recaptured were within a metre (yard) of their original daytime retreat under a log or rock.[131] A similar proportion, when moved experimentally a distance of 30 metres (98 ft), found their way back to their home base.[131] The salamanders left odour marks around their territories which averaged 0.16 to 0.33 square metres (1.7 to 3.6 sq ft) in size and were sometimes inhabited by a male and female pair.[132] These deterred the intrusion of others and delineated the boundaries between neighbouring areas. Much of their behaviour seemed stereotyped and did not involve any actual contact between individuals. An aggressive posture involved raising the body off the ground and glaring at the opponent who often turned away submissively. If the intruder persisted, a biting lunge was usually launched at either the tail region or the naso-labial grooves. Damage to either of these areas can reduce the fitness of the rival, either because of the need to regenerate tissue or because it impairs its ability to detect food.[131]
+
+In frogs, male territorial behaviour is often observed at breeding locations; calling is both an announcement of ownership of part of this resource and an advertisement call to potential mates. In general, a deeper voice represents a heavier and more powerful individual, and this may be sufficient to prevent intrusion by smaller males. Much energy is used in the vocalization and it takes a toll on the territory holder who may be displaced by a fitter rival if he tires. There is a tendency for males to tolerate the holders of neighbouring territories while vigorously attacking unknown intruders. Holders of territories have a "home advantage" and usually come off better in an encounter between two similar-sized frogs. If threats are insufficient, chest to chest tussles may take place. Fighting methods include pushing and shoving, deflating the opponent's vocal sac, seizing him by the head, jumping on his back, biting, chasing, splashing, and ducking him under the water.[133]
+
+Amphibians have soft bodies with thin skins, and lack claws, defensive armour, or spines. Nevertheless, they have evolved various defence mechanisms to keep themselves alive. The first line of defence in salamanders and frogs is the mucous secretion that they produce. This keeps their skin moist and makes them slippery and difficult to grip. The secretion is often sticky and distasteful or toxic.[134] Snakes have been observed yawning and gaping when trying to swallow African clawed frogs (Xenopus laevis), which gives the frogs an opportunity to escape.[134][135] Caecilians have been little studied in this respect, but the Cayenne caecilian (Typhlonectes compressicauda) produces toxic mucus that has killed predatory fish in a feeding experiment in Brazil.[136] In some salamanders, the skin is poisonous. The rough-skinned newt (Taricha granulosa) from North America and other members of its genus contain the neurotoxin tetrodotoxin (TTX), the most toxic non-protein substance known and almost identical to that produced by pufferfish. Handling the newts does not cause harm, but ingestion of even the most minute amounts of the skin is deadly. In feeding trials, fish, frogs, reptiles, birds and mammals were all found to be susceptible.[137][138] The only predators with some tolerance to the poison are certain populations of common garter snake (Thamnophis sirtalis).
+In locations where both snake and salamander co-exist, the snakes have developed immunity through genetic changes and they feed on the amphibians with impunity.[139] Coevolution occurs with the newt increasing its toxic capabilities at the same rate as the snake further develops its immunity.[138] Some frogs and toads are toxic, the main poison glands being at the side of the neck and under the warts on the back. These regions are presented to the attacking animal and their secretions may be foul-tasting or cause various physical or neurological symptoms. Altogether, over 200 toxins have been isolated from the limited number of amphibian species that have been investigated.[140]
+
+Poisonous species often use bright colouring to warn potential predators of their toxicity. These warning colours tend to be red or yellow combined with black, with the fire salamander (Salamandra salamandra) being an example. Once a predator has sampled one of these, it is likely to remember the colouration next time it encounters a similar animal. In some species, such as the fire-bellied toad (Bombina spp.), the warning colouration is on the belly and these animals adopt a defensive pose when attacked, exhibiting their bright colours to the predator. The frog Allobates zaparo is not poisonous, but mimics the appearance of other toxic species in its locality, a strategy that may deceive predators.[142]
+
+Many amphibians are nocturnal and hide during the day, thereby avoiding diurnal predators that hunt by sight. Other amphibians use camouflage to avoid being detected. They have various colourings such as mottled browns, greys and olives to blend into the background. Some salamanders adopt defensive poses when faced by a potential predator such as the North American northern short-tailed shrew (Blarina brevicauda). Their bodies writhe and they raise and lash their tails which makes it difficult for the predator to avoid contact with their poison-producing granular glands.[143] A few salamanders will autotomise their tails when attacked, sacrificing this part of their anatomy to enable them to escape. The tail may have a constriction at its base to allow it to be easily detached. The tail is regenerated later, but the energy cost to the animal of replacing it is significant.[63]
+Some frogs and toads inflate themselves to make themselves look large and fierce, and some spadefoot toads (Pelobates spp) scream and leap towards the attacker.[40] Giant salamanders of the genus Andrias, as well as Ceratophrine and Pyxicephalus frogs possess sharp teeth and are capable of drawing blood with a defensive bite. The blackbelly salamander (Desmognathus quadramaculatus) can bite an attacking common garter snake (Thamnophis sirtalis) two or three times its size on the head and often manages to escape.[144]
+
+In amphibians, there is evidence of habituation, associative learning through both classical and instrumental learning, and discrimination abilities.[145]
+
+In one experiment, when offered live fruit flies (Drosophila virilis), salamanders chose the larger of 1 vs 2 and 2 vs 3. Frogs can distinguish between low numbers (1 vs 2, 2 vs 3, but not 3 vs 4) and large numbers (3 vs 6, 4 vs 8, but not 4 vs 6) of prey. This is irrespective of other characteristics, i.e. surface area, volume, weight and movement, although discrimination among large numbers may be based on surface area.[146]
+
+Dramatic declines in amphibian populations, including population crashes and mass localized extinction, have been noted since the late 1980s from locations all over the world, and amphibian declines are thus perceived to be one of the most critical threats to global biodiversity.[147] In 2004, the International Union for Conservation of Nature (IUCN) reported stating that currently birds,[148] mammals, and amphibians extinction rates were at minimum 48 times greater than natural extinction rates—possibly 1,024 times higher.
+In 2006 there were believed to be 4,035 species of amphibians that depended on water at some stage during their life cycle. Of these, 1,356 (33.6%) were considered to be threatened and this figure is likely to be an underestimate because it excludes 1,427 species for which there was insufficient data to assess their status.[149] A number of causes are believed to be involved, including habitat destruction and modification, over-exploitation, pollution, introduced species, global warming, endocrine-disrupting pollutants, destruction of the ozone layer (ultraviolet radiation has shown to be especially damaging to the skin, eyes, and eggs of amphibians), and diseases like chytridiomycosis. However, many of the causes of amphibian declines are still poorly understood, and are a topic of ongoing discussion.[150]
+
+With their complex reproductive needs and permeable skins, amphibians are often considered to be ecological indicators.[151] In many terrestrial ecosystems, they constitute one of the largest parts of the vertebrate biomass. Any decline in amphibian numbers will affect the patterns of predation. The loss of carnivorous species near the top of the food chain will upset the delicate ecosystem balance and may cause dramatic increases in opportunistic species. In the Middle East, a growing appetite for eating frog legs and the consequent gathering of them for food was linked to an increase in mosquitoes.[152] Predators that feed on amphibians are affected by their decline. The western terrestrial garter snake (Thamnophis elegans) in California is largely aquatic and depends heavily on two species of frog that are decreasing in numbers, the Yosemite toad (Bufo canorus) and the mountain yellow-legged frog (Rana muscosa), putting the snake's future at risk. If the snake were to become scarce, this would affect birds of prey and other predators that feed on it.[153] Meanwhile, in the ponds and lakes, fewer frogs means fewer tadpoles. These normally play an important role in controlling the growth of algae and also forage on detritus that accumulates as sediment on the bottom. A reduction in the number of tadpoles may lead to an overgrowth of algae, resulting in depletion of oxygen in the water when the algae later die and decompose. Aquatic invertebrates and fish might then die and there would be unpredictable ecological consequences.[154]
+
+A global strategy to stem the crisis was released in 2005 in the form of the Amphibian Conservation Action Plan. Developed by over eighty leading experts in the field, this call to action details what would be required to curtail amphibian declines and extinctions over the following five years and how much this would cost. The Amphibian Specialist Group of the IUCN is spearheading efforts to implement a comprehensive global strategy for amphibian conservation.[155] Amphibian Ark is an organization that was formed to implement the ex-situ conservation recommendations of this plan, and they have been working with zoos and aquaria around the world, encouraging them to create assurance colonies of threatened amphibians.[155] One such project is the Panama Amphibian Rescue and Conservation Project that built on existing conservation efforts in Panama to create a country-wide response to the threat of chytridiomycosis.[156]
+

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+
+French (français [fʁɑ̃sɛ] or langue française [lɑ̃ɡ fʁɑ̃sɛːz]) is a Romance language of the Indo-European family. It descended from the Vulgar Latin of the Roman Empire, as did all Romance languages. French evolved from Gallo-Romance, the Latin spoken in Gaul, and more specifically in Northern Gaul. Its closest relatives are the other langues d'oïl—languages historically spoken in northern France and in southern Belgium, which French (Francien) largely supplanted. French was also influenced by native Celtic languages of Northern Roman Gaul like Gallia Belgica and by the (Germanic) Frankish language of the post-Roman Frankish invaders. Today, owing to France's past overseas expansion, there are numerous French-based creole languages, most notably Haitian Creole. A French-speaking person or nation may be referred to as Francophone in both English and French.
+
+French is an official language in 29 countries across multiple continents,[5] most of which are members of the Organisation internationale de la Francophonie (OIF), the community of 84 countries which share the official use or teaching of French. French is also one of six official languages used in the United Nations.[6] It is spoken as a first language (in descending order of the number of speakers) in France, the Canadian provinces of Quebec, Ontario and New Brunswick as well as other Francophone regions, Belgium (Wallonia and the Brussels-Capital Region), western Switzerland (cantons of Bern, Fribourg, Geneva, Jura, Neuchâtel, Vaud, Valais), Monaco, partly in Luxembourg, the states of Louisiana, Maine, New Hampshire and Vermont in the United States, and in northwestern Italy (region of Aosta Valley), and by various communities elsewhere.[7]
+
+In 2015, approximately 40% of the francophone population (including L2 and partial speakers) lived in Europe, 35% in sub-Saharan Africa, 15% in North Africa and the Middle East, 8% in the Americas, and 1% in Asia and Oceania.[8] French is the fourth most widely spoken mother tongue in the European Union.[9] Of Europeans who speak other languages natively, approximately one-fifth are able to speak French as a second language.[10] French is the second most taught foreign language in the EU.[11] French is also the 18th most natively spoken language in the world, 6th most spoken language by total number of speakers and the second or third most studied language worldwide (with about 120 million current learners).[12] As a result of French and Belgian colonialism from the 16th century onward, French was introduced to new territories in the Americas, Africa and Asia. Most second-language speakers reside in Francophone Africa, in particular Gabon, Algeria, Morocco, Tunisia, Mauritius, Senegal and Ivory Coast.[13]
+
+French is estimated to have about 76 million native speakers and about 235 million daily, fluent speakers[14][1][15] and another 77 to 110 million secondary speakers who speak it as a second language to varying degrees of proficiency, mainly in Africa.[16] According to the Organisation internationale de la Francophonie (OIF), approximately 300 million people worldwide are "able to speak the language",[17] without specifying the criteria for this estimation or whom it encompasses.[2] According to a demographic projection led by the Université Laval and the Réseau Démographie de l'Agence universitaire de la francophonie, the total number of French speakers will reach approximately 500 million in 2025 and 650 million by 2050.[18] OIF estimates 700 million by 2050, 80% of whom will be in Africa.[8]
+
+French has a long history as an international language of literature and scientific standards and is a primary or second language of many international organisations including the United Nations, the European Union, the North Atlantic Treaty Organization, the World Trade Organization, the International Olympic Committee, and the International Committee of the Red Cross. In 2011, Bloomberg Businessweek ranked French the third most useful language for business, after English and Standard Mandarin Chinese.[19]
+
+French is a Romance language (meaning that it is descended primarily from Vulgar Latin) that evolved out of the Gallo-Romance dialects spoken in northern France. The language's early forms include Old French and Middle French.
+
+Due to Roman rule, Latin was gradually adopted by the inhabitants of Gaul, and as the language was learned by the common people it developed a distinct local character, with grammatical differences from Latin as spoken elsewhere, some of which being attested on graffiti.[20] This local variety evolved into the Gallo-Romance tongues, which include French and its closest relatives, such as Arpitan.
+
+The evolution of Latin in Gaul was shaped by its coexistence for over half a millennium beside the native Celtic Gaulish language, which did not go extinct until the late 6th century, long after the Fall of the Western Roman Empire.[21] The population remained 90% indigenous in origin,[22][23] and instead of Roman settlers, the Romanizing class was the local native elite, whose children learned Latin in Roman schools; at the time of the collapse of the Empire, this local elite had been slowly abandoning Gaulish entirely, but the rural and lower class populations remained Gaulish speakers who could sometimes also speak Latin or Greek.[24]  The final language shift from Gaulish to Vulgar Latin among rural and lower class populations occurred later, when both they and the incoming Frankish ruler/military class adopted the Gallo-Roman Vulgar Latin speech of the urban intellectual elite.[24]
+
+The Gaulish language likely survived into the 6th century in France, despite considerable Romanization.[21] Coexisting with Latin, Gaulish helped shape the Vulgar Latin dialects that developed into French,[24][21] with effects including loanwords and calques (including oui,[25] the word for "yes"),[26][25] sound changes shaped by Gaulish influence,[27][28] and influences in conjugation and word order.[26][25][20] Recent computational studies suggest that early gender shifts may have been motivated by the gender of the corresponding word in Gaulish.[29]
+
+The beginning of French in Gaul was greatly influenced by Germanic invasions into the country. These invasions had the greatest impact on the northern part of the country and on the language there.[30] A language divide began to grow across the country. The population in the north spoke langue d'oïl while the population in the south spoke langue d'oc.[30] Langue d'oïl grew into what is known as Old French. The period of Old French spanned between the 8th and 14th centuries. Old French shared many characteristics with Latin. For example, Old French made use of different possible word orders just as Latin did because it had a case system that retained the difference between nominative subjects and oblique non-subjects.[31] The period is marked by a heavy superstrate influence from the Germanic Frankish language, which non-exhaustively included the use in upper-class speech and higher registers of V2 word order,[32] a large percentage of the vocabulary (now at around 15% of modern French vocabulary [33]) including the impersonal singular pronoun on (a calque of Germanic man), and the name of the language itself.
+
+Within Old French many dialects emerged but the Francien dialect is one that not only continued but also thrived during the Middle French period (14th century–17th century).[30] Modern French grew out of this Francien dialect.[30] Grammatically, during the period of Middle French, noun declensions were lost and there began to be standardized rules. Robert Estienne published the first Latin-French dictionary, which included information about phonetics, etymology, and grammar.[34] Politically, the Ordinance of Villers-Cotterêts (1539) named French the language of law.
+
+During the 17th century, French replaced Latin as the most important language of diplomacy and international relations (lingua franca). It retained this role until approximately the middle of the 20th century, when it was replaced by English as the United States became the dominant global power following the Second World War.[35][36] Stanley Meisler of the Los Angeles Times said that the fact that the Treaty of Versailles was written in English as well as French was the "first diplomatic blow" against the language.[37]
+
+During the Grand Siècle (17th century), France, under the rule of powerful leaders such as Cardinal Richelieu and Louis XIV, enjoyed a period of prosperity and prominence among European nations. Richelieu established the Académie française to protect the French language. By the early 1800s, Parisian French had become the primary language of the aristocracy in France.
+
+Near the beginning of the 19th century, the French government began to pursue policies with the end goal of eradicating the many minorities and regional languages (patois) spoken in France. This began in 1794 with Henri Grégoire's "Report on the necessity and means to annihilate the patois and to universalize the use of the French language". When public education was made compulsory, only French was taught and the use of any other (patois) language was punished. The goals of the Public School System were made especially clear to the French-speaking teachers sent to teach students in regions such as Occitania and Brittany: "And remember, Gents: you were given your position in order to kill the Breton language" were instructions given from a French official to teachers in the French department of Finistère (western Brittany).[38] The prefect of Basses-Pyrénées in the French Basque Country wrote in 1846: "Our schools in the Basque Country are particularly meant to replace the Basque language with French...".[38] Students were taught that their ancestral languages were inferior and they should be ashamed of them; this process was known in the Occitan-speaking region as Vergonha.
+
+Among the historic reformers of French orthography, such as Louis Maigret, Marle M., Marcellin Berthelot, Philibert Monet, Jacques Peletier du Mans, and Somaize, nowadays the most striking reform is proposed by Mickael Korvin, a Franco-American linguist of Hungarian origin who wants to eliminate accents, silent letters, double letters and more.[39]
+
+Spoken by 19.71% of the European Union's population, French is the third most widely spoken language in the EU, after English and German.[9][41]
+
+Under the Constitution of France, French has been the official language of the Republic since 1992,[42] although the ordinance of Villers-Cotterêts made it mandatory for legal documents in 1539. France mandates the use of French in official government publications, public education except in specific cases, and legal contracts; advertisements must bear a translation of foreign words.
+
+In Belgium, French is the official language of Wallonia (excluding a part of the East Cantons, which are German-speaking) and one of the two official languages—along with Dutch—of the Brussels-Capital Region, where it is spoken by the majority of the population often as their primary language.[43]
+
+French is one of the four official languages of Switzerland, along with German, Italian, and Romansh, and is spoken in the western part of Switzerland, called Romandy, of which Geneva is the largest city. The language divisions in Switzerland do not coincide with political subdivisions, and some cantons have bilingual status: for example, cities such as Biel/Bienne and cantons such as Valais, Fribourg and Berne. French is the native language of about 23% of the Swiss population, and is spoken by 50%[44] of the population.
+
+French is also an official language of Monaco and Luxembourg, as well as in the Aosta Valley region of Italy, while French dialects remain spoken by minorities on the Channel Islands. It is also spoken in Andorra and is the main language after Catalan in El Pas de la Casa. The language is taught as the primary second language in the German land of Saarland, with French being taught from pre-school and over 43% of citizens being able to speak French.[45][46]
+
+The majority of the world's French-speaking population lives in Africa. According to the 2007 report by the Organisation Internationale de la Francophonie, an estimated 115 million African people spread across 31 Francophone countries can speak French as either a first or a second language.[13] This number does not include the people living in non-Francophone African countries who have learned French as a foreign language.[13] Due to the rise of French in Africa, the total French-speaking population worldwide is expected to reach 700 million people in 2050.[49] French is the fastest growing language on the continent (in terms of either official or foreign languages).[50][51]
+French is mostly a second language in Africa, but it has become a first language in some urban areas, such as the region of Abidjan, Ivory Coast[52] and in Libreville, Gabon.[53] There is not a single African French, but multiple forms that diverged through contact with various indigenous African languages.[54]
+
+Sub-Saharan Africa is the region where the French language is most likely to expand, because of the expansion of education and rapid population growth.[55] It is also where the language has evolved the most in recent years.[56][57] Some vernacular forms of French in Africa can be difficult to understand for French speakers from other countries,[58] but written forms of the language are very closely related to those of the rest of the French-speaking world.
+
+French is the second most common language in Canada, after English, and both are official languages at the federal level. It is the first language of 9.5 million people or 29% and the second language for 2.07 million or 6% of the entire population of Canada.[15] French is the sole official language in the province of Quebec, being the mother tongue for some 7 million people, or almost 80% (2006 Census) of the province. About 95% of the people of Quebec speak French as either their first or second language, and for some as their third language. Quebec is also home to the city of Montreal, which is the world's 4th-largest French-speaking city, by number of first language speakers.[59] New Brunswick and Manitoba are the only officially bilingual provinces, though full bilingualism is enacted only in New Brunswick, where about one third of the population is Francophone. French is also an official language of all of the territories (Northwest Territories, Nunavut, and Yukon). Out of the three, Yukon has the most French speakers, comprising just under 4% of the population.[60] Furthermore, while French is not an official language in Ontario, the French Language Services Act ensures that provincial services are to be available in the language. The Act applies to areas of the province where there are significant Francophone communities, namely Eastern Ontario and Northern Ontario. Elsewhere, sizable French-speaking minorities are found in southern Manitoba, Nova Scotia, Prince Edward Island and the Port au Port Peninsula in Newfoundland and Labrador, where the unique Newfoundland French dialect was historically spoken. Smaller pockets of French speakers exist in all other provinces. The Ontarian city of Ottawa, the Canadian capital, is also effectively bilingual, as it has a large population of federal government workers, who are required to offer services in both French and English, and is across a river from Quebec, opposite the major city of Gatineau with which it forms a single metropolitan area.[citation needed]
+
+According to the United States Census Bureau (2011), French is the fourth[61] most-spoken language in the United States after English, Spanish, and Chinese, when all forms of French are considered together and all dialects of Chinese are similarly combined. French remains the second most-spoken language in the states of Louisiana, Maine, Vermont and New Hampshire. Louisiana is home to many distinct dialects, collectively known as Louisiana French. According to the 2000 United States Census, there are over 194,000 people in Louisiana who speak French at home, the most of any state if Creole French is excluded.[62] New England French, essentially a variant of Canadian French, is spoken in parts of New England. Missouri French was historically spoken in Missouri and Illinois (formerly known as Upper Louisiana), but is nearly extinct today.[63]  French also survived in isolated pockets along the Gulf Coast of what was previously French Lower Louisiana, such as Mon Louis Island, Alabama and DeLisle, Mississippi (the latter only being discovered by linguists in the 1990s) but these varieties are severely endangered or presumed extinct.
+
+French is one of Haiti's two official languages. It is the principal language of writing, school instruction, and administrative use. It is spoken by all educated Haitians and is used in the business sector. It is also used for ceremonial events such as weddings, graduations and church masses. About 70–80% of the country's population have Haitian Creole as their first language; the rest speak French as a first language. The second official language is the recently standardized Haitian Creole, which virtually the entire population of Haiti speaks. Haitian Creole is one of the French-based creole languages, drawing the large majority of its vocabulary from French, with influences from West African languages, as well as several European languages. Haitian Creole is closely related to Louisiana Creole and the creole from the Lesser Antilles.[64]
+
+French is the official language of both French Guiana on the South American continent,[65] and of Saint Pierre and Miquelon,[66] an archipelago off the coast of Newfoundland in North America.
+
+French was spoken in French India and is still one of the official languages of Puducherry.[67]
+
+French was the official language of the colony of French Indochina, comprising modern-day Vietnam, Laos, and Cambodia. It continues to be an administrative language in Laos and Cambodia, although its influence has waned in recent years.[68] In colonial Vietnam, the elites primarily spoke French, while many servants who worked in French households spoke a French pidgin known as "Tây Bồi" (now extinct). After French rule ended, South Vietnam continued to use French in administration, education, and trade.[69] Since the Fall of Saigon and the opening of a unified Vietnam's economy, French has gradually been effectively displaced as the main foreign language of choice by English. French nevertheless maintains its colonial legacy by being spoken as a second language by the elderly and elite populations and is presently being revived in higher education and continues to be a diplomatic language in Vietnam. All three countries are official members of the OIF.[70]
+
+A former French mandate, Lebanon designates Arabic as the sole official language, while a special law regulates cases when French can be publicly used. Article 11 of Lebanon's Constitution states that "Arabic is the official national language. A law determines the cases in which the French language is to be used".[71] The French language in Lebanon is a widespread second language among the Lebanese people, and is taught in many schools along with Arabic and English. French is used on Lebanese pound banknotes, on road signs, on Lebanese license plates, and on official buildings (alongside Arabic).
+
+Today, French and English are secondary languages of Lebanon, with about 40% of the population being Francophone and 40% Anglophone.[72] The use of English is growing in the business and media environment. Out of about 900,000 students, about 500,000 are enrolled in Francophone schools, public or private, in which the teaching of mathematics and scientific subjects is provided in French.[73] Actual usage of French varies depending on the region and social status. One-third of high school students educated in French go on to pursue higher education in English-speaking institutions. English is the language of business and communication, with French being an element of social distinction, chosen for its emotional value.[74]
+
+A significant French-speaking community is also present in Israel, primarily among the communities of French Jews in Israel, Moroccan Jews in Israel and Lebanese Jews. Many secondary schools offer French as a foreign language.
+
+The UAE has the status in the Organisation internationale de la Francophonie as an observer state, and Qatar has the status in the organization as an associate state. However, in both countries, French is not spoken by almost any of the general population or migrant workers, but spoken by a small minority of those who invest in Francophone countries or have other financial or family ties. Their entrance as observer and associate states respectively into the organization was aided a good deal by their investments into the Organisation and France itself.[75] A country's status as an observer state in the Organisation internationale de la Francophonie gives the country the right to send representatives to organization meetings and make formal requests to the organization but they do not have voting rights within the OIF.[76] A country's status as an associate state also does not give a country voting abilities but associate states can discuss and review organization matters.[77]
+
+French is an official language of the Pacific Island nation of Vanuatu, where 45% of the population can speak it.[78] In the French special collectivity of New Caledonia, 97% of the population can speak, read and write French[79] while in French Polynesia this figure is 95%,[80] and in the French collectivity of Wallis and Futuna, it is 84%.[81]
+
+In French Polynesia and to a lesser extent Wallis and Futuna, where oral and written knowledge of the French language has become almost nearly universal (95% and 84% respectively), French increasingly tends to displace the native Polynesian languages as the language most spoken at home. In French Polynesia, the percentage of the population who reported that French was the language they use the most at home rose from 67% at the 2007 census to 74% at the 2017 census.[82][80] In Wallis and Futuna, the percentage of the population who reported that French was the language they use the most at home rose from 10% at the 2008 census to 13% at the 2018 census.[81][83]
+
+The future of the French language is often discussed in the news. For example, in 2014, The New York Times documented an increase in the teaching of French in New York, especially in K-12 dual-language programs where Spanish and Mandarin are the only second-language options more popular than French.[84] In a study published in March 2014 by Forbes, the investment bank Natixis said that French could become the world's most spoken language by 2050. It noted that French is spreading in areas where the population is rapidly increasing, especially in sub-Saharan Africa.[85]
+
+French is taught in universities around the world, and is one of the world's most influential languages because of its wide use in the worlds of journalism, jurisprudence, education, and diplomacy.[86]
+In diplomacy, French is one of the six official languages of the United Nations (and one of the UN Secretariat's only two working languages[87]), one of twenty official and three working languages of the European Union, an official language of NATO, the International Olympic Committee, the Council of Europe, the Organisation for Economic Co-operation and Development, Organization of American States (alongside Spanish, Portuguese and English), the Eurovision Song Contest, one of eighteen official languages of the European Space Agency, World Trade Organization and the least used of the three official languages in the North American Free Trade Agreement countries. It is also a working language in nonprofit organisations such as the Red Cross (alongside English, German, Spanish, Portuguese, Arabic and Russian), Amnesty International (alongside 32 other languages of which English is the most used, followed by Spanish, Portuguese, German, and Italian), Médecins sans Frontières (used alongside English, Spanish, Portuguese and Arabic), and Médecins du Monde (used alongside English).[88] Given the demographic prospects of the French-speaking nations of Africa, researcher Pascal-Emmanuel Gobry wrote in 2014 that French "could be the language of the future".[89]
+
+Significant as a judicial language, French is one of the official languages of such major international and regional courts, tribunals, and dispute-settlement bodies as the African Court on Human and Peoples' Rights, the Caribbean Court of Justice, the Court of Justice for the Economic Community of West African States, the Inter-American Court of Human Rights, the International Court of Justice, the International Criminal Tribunal for the former Yugoslavia, International Criminal Tribunal for Rwanda, the International Tribunal for the Law of the Sea the International Criminal Court and the World Trade Organization Appellate Body. It is the sole internal working language of the Court of Justice of the European Union, and makes with English the European Court of Human Rights's two working languages.[90]
+
+In 1997, George Werber published, in Language Today, a comprehensive academic study entitled "The World's 10 most influential languages".[91] In the article, Werber ranked French as, after English, the second most influential language of the world, ahead of Spanish.[91] His criteria were the numbers of native speakers, the number of secondary speakers (especially high for French among fellow world languages), the number of countries using the language and their respective populations, the economic power of the countries using the language, the number of major areas in which the language is used,  and the linguistic prestige associated with the mastery of the language (Werber highlighted that French in particular enjoys considerable linguistic prestige).[91] In a 2008 reassessment of his article, Werber concluded that his findings were still correct since "the situation among the top ten remains unchanged."[91]
+
+Knowledge of French is often considered to be a useful skill by business owners in the United Kingdom; a 2014 study found that 50% of British managers considered French to be a valuable asset for their business, thus ranking French as the most sought-after foreign language there, ahead of German (49%) and Spanish (44%).[92] MIT economist Albert Saiz calculated a 2.3% premium for those who have French as a foreign language in the workplace.[93]
+
+In English-speaking Canada, the United Kingdom, and the Republic of Ireland, French is the first foreign language taught and in number of pupils is far ahead of other languages. In the United States, Spanish is the most commonly taught foreign language in schools and universities, though French is next. In some areas of the country nearest to French-speaking Quebec, it is the language more commonly taught.
+
+Vowel phonemes in French
+
+Although there are many French regional accents, foreign learners normally use only one variety of the language.
+
+French pronunciation follows strict rules based on spelling, but French spelling is often based more on history than phonology. The rules for pronunciation vary between dialects, but the standard rules are:
+
+French is written with the 26 letters of the basic Latin script, with four diacritics appearing on vowels (circumflex accent, acute accent, grave accent, diaeresis) and the cedilla appearing in "ç".
+
+There are two ligatures, "œ" and "æ", but they are often replaced in contemporary French with "oe" and "ae", because the ligatures do not appear on the AZERTY keyboard layout used in French-speaking countries. However this is nonstandard in formal and literary texts.
+
+French spelling, like English spelling, tends to preserve obsolete pronunciation rules. This is mainly due to extreme phonetic changes since the Old French period, without a corresponding change in spelling. Moreover, some conscious changes were made to restore Latin orthography (as with some English words such as "debt"):
+
+French is a morphophonemic language. While it contains 130 graphemes that denote only 36 phonemes, many of its spelling rules are likely due to a consistency in morphemic patterns such as adding suffixes and prefixes.[94] Many given spellings of common morphemes usually lead to a predictable sound. In particular, a given vowel combination or diacritic generally leads to one phoneme. However, there is not a one-to-one relation of a phoneme and a single related grapheme, which can be seen in how tomber and tombé both end with the /e/ phoneme.[95] Additionally, there are many variations in the pronunciation of consonants at the end of words, demonstrated by how the x in paix is not pronounced though at the end of Aix it is.
+
+As a result, it can be difficult to predict the spelling of a word based on the sound. Final consonants are generally silent, except when the following word begins with a vowel (see Liaison (French)). For example, the following words end in a vowel sound: pied, aller, les, finit, beaux. The same words followed by a vowel, however, may sound the consonants, as they do in these examples: beaux-arts, les amis, pied-à-terre.
+
+French writing, as with any language, is affected by the spoken language. In Old French, the plural for animal was animals. The /als/ sequence was unstable and was turned into a diphthong /aus/. This change was then reflected in the orthography: animaus. The us ending, very common in Latin, was then abbreviated by copyists (monks) by the letter x, resulting in a written form animax. As the French language further evolved, the pronunciation of au turned into /o/ so that the u was reestablished in orthography for consistency, resulting in modern French animaux (pronounced first /animos/ before the final /s/ was dropped in contemporary French). The same is true for cheval pluralized as chevaux and many others. In addition, castel pl. castels became château pl. châteaux.
+
+Some proposals exist to simplify the existing writing system, but they still fail to gather interest.[96][97][98][99]
+
+In 1990, a reform accepted some changes to French orthography. At the time the proposed changes were considered to be suggestions. In 2016, schoolbooks in France began to use the newer recommended spellings, with instruction to teachers that both old and new spellings be deemed correct.[100]
+
+French is a moderately inflected language. Nouns and most pronouns are inflected for number (singular or plural, though in most nouns the plural is pronounced the same as the singular even if spelled differently); adjectives, for number and gender (masculine or feminine) of their nouns; personal pronouns and a few other pronouns, for person, number, gender, and case; and verbs, for tense, aspect, mood, and the person and number of their subjects. Case is primarily marked using word order and prepositions, while certain verb features are marked using auxiliary verbs. According to the French lexicogrammatical system, French has a rank-scale hierarchy with clause as the top rank, which is followed by group rank, word rank, and morpheme rank. A French clause is made up of groups, groups are made up of words, and lastly, words are made up of morphemes.[101]
+
+French grammar shares several notable features with most other Romance languages, including
+
+Every French noun is either masculine or feminine. Because French nouns are not inflected for gender, a noun's form cannot specify its gender. For nouns regarding the living, their grammatical genders often correspond to that which they refer to. For example, a male teacher is a "enseignant" while a female teacher is a "enseignante". However, plural nouns that refer to a group that includes both masculine and feminine entities are always masculine. So a group of two male teachers would be "enseignants". A group of two male teachers and two female teachers would still be "enseignants". In many situations, and in the case of "enseignant", both the singular and plural form of a noun are pronounced identically. The article used for singular nouns is different from that used for plural nouns and the article provides a distinguishing factor between the two in speech. For example, the singular "le professeur" or "la professeur(e)" (the male or female teacher, professor) can be distinguished from the plural "les professeurs" because "le", "la", and "les" are all pronounced differently. There are some situations where both the feminine and masculine form of a noun are the same and the article provides the only difference. For example, "le dentiste" refers to a male dentist while "la dentiste" refers to a female dentist.
+
+The French language consists of both finite and non-finite moods. The finite moods include the indicative mood (indicatif), the subjunctive mood (subjonctif), the imperative mood (impératif), and the conditional mood (conditionnel). The non-finite moods include the infinitive mood (infinitif), the present participle (participe présent), and the past participle (participe passé).
+
+The indicative mood makes use of eight tense-aspect forms. These include the present (présent), the simple past (passé composé and passé simple), the past imperfective (imparfait), the pluperfect (plus-que-parfait), the simple future (futur simple), the future perfect (futur antérieur), and the past perfect (passé antérieur). Some forms are less commonly used today. In today's spoken French, the passé composé is used while the passé simple is reserved for formal situations or for literary purposes. Similarly, the plus-que-parfait is used for speaking rather than the older passé antérieur seen in literary works.
+
+Within the indicative mood, the passé composé, plus-que-parfait, futur antérieur, and passé antérieur all use auxiliary verbs in their forms.
+
+The subjunctive mood only includes four of the tense-aspect forms found in the indicative: present (présent), simple past (passé composé), past imperfective (imparfait), and pluperfect (plus-que-parfait).
+
+Within the subjunctive mood, the passé composé and plus-que-parfait use auxiliary verbs in their forms.
+
+The imperative is used in the present tense (with the exception of a few instances where it is used in the perfect tense). The imperative is used to give commands to you (tu), we/us (nous), and plural you (vous).
+
+The conditional makes use of the present (présent) and the past (passé).
+
+The passé uses auxiliary verbs in its forms.
+
+French uses both the active voice and the passive voice. The active voice is unmarked while the passive voice is formed by using a form of verb être ("to be") and the past participle.
+
+Example of the active voice:
+
+Example of the passive voice:
+
+French declarative word order is subject–verb–object although a pronoun object precedes the verb. Some types of sentences allow for or require different word orders, in particular inversion of the subject and verb like "Parlez-vous français?" when asking a question rather than just "Vous parlez français ?" Both questions mean the same thing; however, a rising inflection is always used on both of them whenever asking a question, especially on the second one. Specifically, the first translates into "Do you speak French?" while the second one is literally just "You speak French?" To avoid inversion while asking a question, 'Est-ce que' (literally 'is it that') may be placed in the beginning of the sentence. "Parlez-vous français ?" may become "Est-ce que vous parlez français ?" French also uses verb–object–subject (VOS) and object–subject–verb (OSV) word order. OSV word order is not used often and VOS is reserved for formal writings.[31]
+
+The majority of French words derive from Vulgar Latin or were constructed from Latin or Greek roots. In many cases a single etymological root appears in French in a "popular" or native form, inherited from Vulgar Latin, and a learned form, borrowed later from Classical Latin. The following pairs consist of a native noun and a learned adjective:
+
+However, a historical tendency to gallicise Latin roots can be identified, whereas English conversely leans towards a more direct incorporation of the Latin:
+
+There are also noun-noun and adjective-adjective pairs:
+
+It can be difficult to identify the Latin source of native French words, because in the evolution from Vulgar Latin, unstressed syllables were severely reduced and the remaining vowels and consonants underwent significant modifications.
+
+More recently the linguistic policy of the French language academies of France and Quebec has been to provide French equivalents to (mainly English) imported words, either by using existing vocabulary, extending its meaning or deriving a new word according to French morphological rules. The result is often two (or more) co-existing terms for describing the same phenomenon.
+
+Root languages of loanwords[102]
+
+It is estimated that 12% (4,200) of common French words found in a typical dictionary such as the Petit Larousse or Micro-Robert Plus (35,000 words) are of foreign origin (where Greek and Latin learned words are not seen as foreign). About 25% (1,054) of these foreign words come from English and are fairly recent borrowings. The others are some 707 words from Italian, 550 from ancient Germanic languages, 481 from other Gallo-Romance languages, 215 from Arabic, 164 from German, 160 from Celtic languages, 159 from Spanish, 153 from Dutch, 112 from Persian and Sanskrit, 101 from Native American languages, 89 from other Asian languages, 56 from other Afro-Asiatic languages, 55 from Slavic languages and Baltic languages, 10 from Basque and 144 (about 3%) from other languages.[102]
+
+One study analyzing the degree of differentiation of Romance languages in comparison to Latin estimated that among the languages analyzed French has the greatest distance from Latin.[103] Lexical similarity is 89% with Italian, 80% with Sardinian, 78% with Rhaeto-Romance, and 75% with Romanian, Spanish and Portuguese.[104][105][104]
+
+The French counting system is partially vigesimal: twenty (vingt) is used as a base number in the names of numbers from 70 to 99. The French word for 80 is quatre-vingts, literally "four twenties", and the word for 75 is soixante-quinze, literally "sixty-fifteen". This reform arose after the French Revolution to unify the counting systems (mostly vigesimal near the coast, because of Celtic (via Breton) and Viking influences. This system is comparable to the archaic English use of score, as in "fourscore and seven" (87), or "threescore and ten" (70).
+
+In Old French (during the Middle Ages), all numbers from 30 to 99 could be said in either base 10 or base 20, e.g. vint et doze (twenty and twelve) for 32, dous vinz et diz (two twenties and ten) for 50, uitante for 80, or nonante for 90.[106]
+
+Belgian French, Swiss French, Aostan French[107] and the French used in the Democratic Republic of the Congo, Rwanda and Burundi are different in this respect. In the French spoken in these places, 70 and 90 are septante and nonante. In Switzerland, depending on the local dialect, 80 can be quatre-vingts (Geneva, Neuchâtel, Jura) or huitante (Vaud, Valais, Fribourg). Octante had been used in Switzerland in the past, but is now considered archaic,[108] while in the Aosta Valley 80 is huitante.[107] In Belgium and in its former African colonies, however, quatre-vingts is universally used.
+
+French, like most European languages, uses a space to separate thousands.[109] The comma is used in French numbers as a decimal point, i.e. "2,5" instead of "2.5".
+
+Notes
+

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+
+
+French (français [fʁɑ̃sɛ] or langue française [lɑ̃ɡ fʁɑ̃sɛːz]) is a Romance language of the Indo-European family. It descended from the Vulgar Latin of the Roman Empire, as did all Romance languages. French evolved from Gallo-Romance, the Latin spoken in Gaul, and more specifically in Northern Gaul. Its closest relatives are the other langues d'oïl—languages historically spoken in northern France and in southern Belgium, which French (Francien) largely supplanted. French was also influenced by native Celtic languages of Northern Roman Gaul like Gallia Belgica and by the (Germanic) Frankish language of the post-Roman Frankish invaders. Today, owing to France's past overseas expansion, there are numerous French-based creole languages, most notably Haitian Creole. A French-speaking person or nation may be referred to as Francophone in both English and French.
+
+French is an official language in 29 countries across multiple continents,[5] most of which are members of the Organisation internationale de la Francophonie (OIF), the community of 84 countries which share the official use or teaching of French. French is also one of six official languages used in the United Nations.[6] It is spoken as a first language (in descending order of the number of speakers) in France, the Canadian provinces of Quebec, Ontario and New Brunswick as well as other Francophone regions, Belgium (Wallonia and the Brussels-Capital Region), western Switzerland (cantons of Bern, Fribourg, Geneva, Jura, Neuchâtel, Vaud, Valais), Monaco, partly in Luxembourg, the states of Louisiana, Maine, New Hampshire and Vermont in the United States, and in northwestern Italy (region of Aosta Valley), and by various communities elsewhere.[7]
+
+In 2015, approximately 40% of the francophone population (including L2 and partial speakers) lived in Europe, 35% in sub-Saharan Africa, 15% in North Africa and the Middle East, 8% in the Americas, and 1% in Asia and Oceania.[8] French is the fourth most widely spoken mother tongue in the European Union.[9] Of Europeans who speak other languages natively, approximately one-fifth are able to speak French as a second language.[10] French is the second most taught foreign language in the EU.[11] French is also the 18th most natively spoken language in the world, 6th most spoken language by total number of speakers and the second or third most studied language worldwide (with about 120 million current learners).[12] As a result of French and Belgian colonialism from the 16th century onward, French was introduced to new territories in the Americas, Africa and Asia. Most second-language speakers reside in Francophone Africa, in particular Gabon, Algeria, Morocco, Tunisia, Mauritius, Senegal and Ivory Coast.[13]
+
+French is estimated to have about 76 million native speakers and about 235 million daily, fluent speakers[14][1][15] and another 77 to 110 million secondary speakers who speak it as a second language to varying degrees of proficiency, mainly in Africa.[16] According to the Organisation internationale de la Francophonie (OIF), approximately 300 million people worldwide are "able to speak the language",[17] without specifying the criteria for this estimation or whom it encompasses.[2] According to a demographic projection led by the Université Laval and the Réseau Démographie de l'Agence universitaire de la francophonie, the total number of French speakers will reach approximately 500 million in 2025 and 650 million by 2050.[18] OIF estimates 700 million by 2050, 80% of whom will be in Africa.[8]
+
+French has a long history as an international language of literature and scientific standards and is a primary or second language of many international organisations including the United Nations, the European Union, the North Atlantic Treaty Organization, the World Trade Organization, the International Olympic Committee, and the International Committee of the Red Cross. In 2011, Bloomberg Businessweek ranked French the third most useful language for business, after English and Standard Mandarin Chinese.[19]
+
+French is a Romance language (meaning that it is descended primarily from Vulgar Latin) that evolved out of the Gallo-Romance dialects spoken in northern France. The language's early forms include Old French and Middle French.
+
+Due to Roman rule, Latin was gradually adopted by the inhabitants of Gaul, and as the language was learned by the common people it developed a distinct local character, with grammatical differences from Latin as spoken elsewhere, some of which being attested on graffiti.[20] This local variety evolved into the Gallo-Romance tongues, which include French and its closest relatives, such as Arpitan.
+
+The evolution of Latin in Gaul was shaped by its coexistence for over half a millennium beside the native Celtic Gaulish language, which did not go extinct until the late 6th century, long after the Fall of the Western Roman Empire.[21] The population remained 90% indigenous in origin,[22][23] and instead of Roman settlers, the Romanizing class was the local native elite, whose children learned Latin in Roman schools; at the time of the collapse of the Empire, this local elite had been slowly abandoning Gaulish entirely, but the rural and lower class populations remained Gaulish speakers who could sometimes also speak Latin or Greek.[24]  The final language shift from Gaulish to Vulgar Latin among rural and lower class populations occurred later, when both they and the incoming Frankish ruler/military class adopted the Gallo-Roman Vulgar Latin speech of the urban intellectual elite.[24]
+
+The Gaulish language likely survived into the 6th century in France, despite considerable Romanization.[21] Coexisting with Latin, Gaulish helped shape the Vulgar Latin dialects that developed into French,[24][21] with effects including loanwords and calques (including oui,[25] the word for "yes"),[26][25] sound changes shaped by Gaulish influence,[27][28] and influences in conjugation and word order.[26][25][20] Recent computational studies suggest that early gender shifts may have been motivated by the gender of the corresponding word in Gaulish.[29]
+
+The beginning of French in Gaul was greatly influenced by Germanic invasions into the country. These invasions had the greatest impact on the northern part of the country and on the language there.[30] A language divide began to grow across the country. The population in the north spoke langue d'oïl while the population in the south spoke langue d'oc.[30] Langue d'oïl grew into what is known as Old French. The period of Old French spanned between the 8th and 14th centuries. Old French shared many characteristics with Latin. For example, Old French made use of different possible word orders just as Latin did because it had a case system that retained the difference between nominative subjects and oblique non-subjects.[31] The period is marked by a heavy superstrate influence from the Germanic Frankish language, which non-exhaustively included the use in upper-class speech and higher registers of V2 word order,[32] a large percentage of the vocabulary (now at around 15% of modern French vocabulary [33]) including the impersonal singular pronoun on (a calque of Germanic man), and the name of the language itself.
+
+Within Old French many dialects emerged but the Francien dialect is one that not only continued but also thrived during the Middle French period (14th century–17th century).[30] Modern French grew out of this Francien dialect.[30] Grammatically, during the period of Middle French, noun declensions were lost and there began to be standardized rules. Robert Estienne published the first Latin-French dictionary, which included information about phonetics, etymology, and grammar.[34] Politically, the Ordinance of Villers-Cotterêts (1539) named French the language of law.
+
+During the 17th century, French replaced Latin as the most important language of diplomacy and international relations (lingua franca). It retained this role until approximately the middle of the 20th century, when it was replaced by English as the United States became the dominant global power following the Second World War.[35][36] Stanley Meisler of the Los Angeles Times said that the fact that the Treaty of Versailles was written in English as well as French was the "first diplomatic blow" against the language.[37]
+
+During the Grand Siècle (17th century), France, under the rule of powerful leaders such as Cardinal Richelieu and Louis XIV, enjoyed a period of prosperity and prominence among European nations. Richelieu established the Académie française to protect the French language. By the early 1800s, Parisian French had become the primary language of the aristocracy in France.
+
+Near the beginning of the 19th century, the French government began to pursue policies with the end goal of eradicating the many minorities and regional languages (patois) spoken in France. This began in 1794 with Henri Grégoire's "Report on the necessity and means to annihilate the patois and to universalize the use of the French language". When public education was made compulsory, only French was taught and the use of any other (patois) language was punished. The goals of the Public School System were made especially clear to the French-speaking teachers sent to teach students in regions such as Occitania and Brittany: "And remember, Gents: you were given your position in order to kill the Breton language" were instructions given from a French official to teachers in the French department of Finistère (western Brittany).[38] The prefect of Basses-Pyrénées in the French Basque Country wrote in 1846: "Our schools in the Basque Country are particularly meant to replace the Basque language with French...".[38] Students were taught that their ancestral languages were inferior and they should be ashamed of them; this process was known in the Occitan-speaking region as Vergonha.
+
+Among the historic reformers of French orthography, such as Louis Maigret, Marle M., Marcellin Berthelot, Philibert Monet, Jacques Peletier du Mans, and Somaize, nowadays the most striking reform is proposed by Mickael Korvin, a Franco-American linguist of Hungarian origin who wants to eliminate accents, silent letters, double letters and more.[39]
+
+Spoken by 19.71% of the European Union's population, French is the third most widely spoken language in the EU, after English and German.[9][41]
+
+Under the Constitution of France, French has been the official language of the Republic since 1992,[42] although the ordinance of Villers-Cotterêts made it mandatory for legal documents in 1539. France mandates the use of French in official government publications, public education except in specific cases, and legal contracts; advertisements must bear a translation of foreign words.
+
+In Belgium, French is the official language of Wallonia (excluding a part of the East Cantons, which are German-speaking) and one of the two official languages—along with Dutch—of the Brussels-Capital Region, where it is spoken by the majority of the population often as their primary language.[43]
+
+French is one of the four official languages of Switzerland, along with German, Italian, and Romansh, and is spoken in the western part of Switzerland, called Romandy, of which Geneva is the largest city. The language divisions in Switzerland do not coincide with political subdivisions, and some cantons have bilingual status: for example, cities such as Biel/Bienne and cantons such as Valais, Fribourg and Berne. French is the native language of about 23% of the Swiss population, and is spoken by 50%[44] of the population.
+
+French is also an official language of Monaco and Luxembourg, as well as in the Aosta Valley region of Italy, while French dialects remain spoken by minorities on the Channel Islands. It is also spoken in Andorra and is the main language after Catalan in El Pas de la Casa. The language is taught as the primary second language in the German land of Saarland, with French being taught from pre-school and over 43% of citizens being able to speak French.[45][46]
+
+The majority of the world's French-speaking population lives in Africa. According to the 2007 report by the Organisation Internationale de la Francophonie, an estimated 115 million African people spread across 31 Francophone countries can speak French as either a first or a second language.[13] This number does not include the people living in non-Francophone African countries who have learned French as a foreign language.[13] Due to the rise of French in Africa, the total French-speaking population worldwide is expected to reach 700 million people in 2050.[49] French is the fastest growing language on the continent (in terms of either official or foreign languages).[50][51]
+French is mostly a second language in Africa, but it has become a first language in some urban areas, such as the region of Abidjan, Ivory Coast[52] and in Libreville, Gabon.[53] There is not a single African French, but multiple forms that diverged through contact with various indigenous African languages.[54]
+
+Sub-Saharan Africa is the region where the French language is most likely to expand, because of the expansion of education and rapid population growth.[55] It is also where the language has evolved the most in recent years.[56][57] Some vernacular forms of French in Africa can be difficult to understand for French speakers from other countries,[58] but written forms of the language are very closely related to those of the rest of the French-speaking world.
+
+French is the second most common language in Canada, after English, and both are official languages at the federal level. It is the first language of 9.5 million people or 29% and the second language for 2.07 million or 6% of the entire population of Canada.[15] French is the sole official language in the province of Quebec, being the mother tongue for some 7 million people, or almost 80% (2006 Census) of the province. About 95% of the people of Quebec speak French as either their first or second language, and for some as their third language. Quebec is also home to the city of Montreal, which is the world's 4th-largest French-speaking city, by number of first language speakers.[59] New Brunswick and Manitoba are the only officially bilingual provinces, though full bilingualism is enacted only in New Brunswick, where about one third of the population is Francophone. French is also an official language of all of the territories (Northwest Territories, Nunavut, and Yukon). Out of the three, Yukon has the most French speakers, comprising just under 4% of the population.[60] Furthermore, while French is not an official language in Ontario, the French Language Services Act ensures that provincial services are to be available in the language. The Act applies to areas of the province where there are significant Francophone communities, namely Eastern Ontario and Northern Ontario. Elsewhere, sizable French-speaking minorities are found in southern Manitoba, Nova Scotia, Prince Edward Island and the Port au Port Peninsula in Newfoundland and Labrador, where the unique Newfoundland French dialect was historically spoken. Smaller pockets of French speakers exist in all other provinces. The Ontarian city of Ottawa, the Canadian capital, is also effectively bilingual, as it has a large population of federal government workers, who are required to offer services in both French and English, and is across a river from Quebec, opposite the major city of Gatineau with which it forms a single metropolitan area.[citation needed]
+
+According to the United States Census Bureau (2011), French is the fourth[61] most-spoken language in the United States after English, Spanish, and Chinese, when all forms of French are considered together and all dialects of Chinese are similarly combined. French remains the second most-spoken language in the states of Louisiana, Maine, Vermont and New Hampshire. Louisiana is home to many distinct dialects, collectively known as Louisiana French. According to the 2000 United States Census, there are over 194,000 people in Louisiana who speak French at home, the most of any state if Creole French is excluded.[62] New England French, essentially a variant of Canadian French, is spoken in parts of New England. Missouri French was historically spoken in Missouri and Illinois (formerly known as Upper Louisiana), but is nearly extinct today.[63]  French also survived in isolated pockets along the Gulf Coast of what was previously French Lower Louisiana, such as Mon Louis Island, Alabama and DeLisle, Mississippi (the latter only being discovered by linguists in the 1990s) but these varieties are severely endangered or presumed extinct.
+
+French is one of Haiti's two official languages. It is the principal language of writing, school instruction, and administrative use. It is spoken by all educated Haitians and is used in the business sector. It is also used for ceremonial events such as weddings, graduations and church masses. About 70–80% of the country's population have Haitian Creole as their first language; the rest speak French as a first language. The second official language is the recently standardized Haitian Creole, which virtually the entire population of Haiti speaks. Haitian Creole is one of the French-based creole languages, drawing the large majority of its vocabulary from French, with influences from West African languages, as well as several European languages. Haitian Creole is closely related to Louisiana Creole and the creole from the Lesser Antilles.[64]
+
+French is the official language of both French Guiana on the South American continent,[65] and of Saint Pierre and Miquelon,[66] an archipelago off the coast of Newfoundland in North America.
+
+French was spoken in French India and is still one of the official languages of Puducherry.[67]
+
+French was the official language of the colony of French Indochina, comprising modern-day Vietnam, Laos, and Cambodia. It continues to be an administrative language in Laos and Cambodia, although its influence has waned in recent years.[68] In colonial Vietnam, the elites primarily spoke French, while many servants who worked in French households spoke a French pidgin known as "Tây Bồi" (now extinct). After French rule ended, South Vietnam continued to use French in administration, education, and trade.[69] Since the Fall of Saigon and the opening of a unified Vietnam's economy, French has gradually been effectively displaced as the main foreign language of choice by English. French nevertheless maintains its colonial legacy by being spoken as a second language by the elderly and elite populations and is presently being revived in higher education and continues to be a diplomatic language in Vietnam. All three countries are official members of the OIF.[70]
+
+A former French mandate, Lebanon designates Arabic as the sole official language, while a special law regulates cases when French can be publicly used. Article 11 of Lebanon's Constitution states that "Arabic is the official national language. A law determines the cases in which the French language is to be used".[71] The French language in Lebanon is a widespread second language among the Lebanese people, and is taught in many schools along with Arabic and English. French is used on Lebanese pound banknotes, on road signs, on Lebanese license plates, and on official buildings (alongside Arabic).
+
+Today, French and English are secondary languages of Lebanon, with about 40% of the population being Francophone and 40% Anglophone.[72] The use of English is growing in the business and media environment. Out of about 900,000 students, about 500,000 are enrolled in Francophone schools, public or private, in which the teaching of mathematics and scientific subjects is provided in French.[73] Actual usage of French varies depending on the region and social status. One-third of high school students educated in French go on to pursue higher education in English-speaking institutions. English is the language of business and communication, with French being an element of social distinction, chosen for its emotional value.[74]
+
+A significant French-speaking community is also present in Israel, primarily among the communities of French Jews in Israel, Moroccan Jews in Israel and Lebanese Jews. Many secondary schools offer French as a foreign language.
+
+The UAE has the status in the Organisation internationale de la Francophonie as an observer state, and Qatar has the status in the organization as an associate state. However, in both countries, French is not spoken by almost any of the general population or migrant workers, but spoken by a small minority of those who invest in Francophone countries or have other financial or family ties. Their entrance as observer and associate states respectively into the organization was aided a good deal by their investments into the Organisation and France itself.[75] A country's status as an observer state in the Organisation internationale de la Francophonie gives the country the right to send representatives to organization meetings and make formal requests to the organization but they do not have voting rights within the OIF.[76] A country's status as an associate state also does not give a country voting abilities but associate states can discuss and review organization matters.[77]
+
+French is an official language of the Pacific Island nation of Vanuatu, where 45% of the population can speak it.[78] In the French special collectivity of New Caledonia, 97% of the population can speak, read and write French[79] while in French Polynesia this figure is 95%,[80] and in the French collectivity of Wallis and Futuna, it is 84%.[81]
+
+In French Polynesia and to a lesser extent Wallis and Futuna, where oral and written knowledge of the French language has become almost nearly universal (95% and 84% respectively), French increasingly tends to displace the native Polynesian languages as the language most spoken at home. In French Polynesia, the percentage of the population who reported that French was the language they use the most at home rose from 67% at the 2007 census to 74% at the 2017 census.[82][80] In Wallis and Futuna, the percentage of the population who reported that French was the language they use the most at home rose from 10% at the 2008 census to 13% at the 2018 census.[81][83]
+
+The future of the French language is often discussed in the news. For example, in 2014, The New York Times documented an increase in the teaching of French in New York, especially in K-12 dual-language programs where Spanish and Mandarin are the only second-language options more popular than French.[84] In a study published in March 2014 by Forbes, the investment bank Natixis said that French could become the world's most spoken language by 2050. It noted that French is spreading in areas where the population is rapidly increasing, especially in sub-Saharan Africa.[85]
+
+French is taught in universities around the world, and is one of the world's most influential languages because of its wide use in the worlds of journalism, jurisprudence, education, and diplomacy.[86]
+In diplomacy, French is one of the six official languages of the United Nations (and one of the UN Secretariat's only two working languages[87]), one of twenty official and three working languages of the European Union, an official language of NATO, the International Olympic Committee, the Council of Europe, the Organisation for Economic Co-operation and Development, Organization of American States (alongside Spanish, Portuguese and English), the Eurovision Song Contest, one of eighteen official languages of the European Space Agency, World Trade Organization and the least used of the three official languages in the North American Free Trade Agreement countries. It is also a working language in nonprofit organisations such as the Red Cross (alongside English, German, Spanish, Portuguese, Arabic and Russian), Amnesty International (alongside 32 other languages of which English is the most used, followed by Spanish, Portuguese, German, and Italian), Médecins sans Frontières (used alongside English, Spanish, Portuguese and Arabic), and Médecins du Monde (used alongside English).[88] Given the demographic prospects of the French-speaking nations of Africa, researcher Pascal-Emmanuel Gobry wrote in 2014 that French "could be the language of the future".[89]
+
+Significant as a judicial language, French is one of the official languages of such major international and regional courts, tribunals, and dispute-settlement bodies as the African Court on Human and Peoples' Rights, the Caribbean Court of Justice, the Court of Justice for the Economic Community of West African States, the Inter-American Court of Human Rights, the International Court of Justice, the International Criminal Tribunal for the former Yugoslavia, International Criminal Tribunal for Rwanda, the International Tribunal for the Law of the Sea the International Criminal Court and the World Trade Organization Appellate Body. It is the sole internal working language of the Court of Justice of the European Union, and makes with English the European Court of Human Rights's two working languages.[90]
+
+In 1997, George Werber published, in Language Today, a comprehensive academic study entitled "The World's 10 most influential languages".[91] In the article, Werber ranked French as, after English, the second most influential language of the world, ahead of Spanish.[91] His criteria were the numbers of native speakers, the number of secondary speakers (especially high for French among fellow world languages), the number of countries using the language and their respective populations, the economic power of the countries using the language, the number of major areas in which the language is used,  and the linguistic prestige associated with the mastery of the language (Werber highlighted that French in particular enjoys considerable linguistic prestige).[91] In a 2008 reassessment of his article, Werber concluded that his findings were still correct since "the situation among the top ten remains unchanged."[91]
+
+Knowledge of French is often considered to be a useful skill by business owners in the United Kingdom; a 2014 study found that 50% of British managers considered French to be a valuable asset for their business, thus ranking French as the most sought-after foreign language there, ahead of German (49%) and Spanish (44%).[92] MIT economist Albert Saiz calculated a 2.3% premium for those who have French as a foreign language in the workplace.[93]
+
+In English-speaking Canada, the United Kingdom, and the Republic of Ireland, French is the first foreign language taught and in number of pupils is far ahead of other languages. In the United States, Spanish is the most commonly taught foreign language in schools and universities, though French is next. In some areas of the country nearest to French-speaking Quebec, it is the language more commonly taught.
+
+Vowel phonemes in French
+
+Although there are many French regional accents, foreign learners normally use only one variety of the language.
+
+French pronunciation follows strict rules based on spelling, but French spelling is often based more on history than phonology. The rules for pronunciation vary between dialects, but the standard rules are:
+
+French is written with the 26 letters of the basic Latin script, with four diacritics appearing on vowels (circumflex accent, acute accent, grave accent, diaeresis) and the cedilla appearing in "ç".
+
+There are two ligatures, "œ" and "æ", but they are often replaced in contemporary French with "oe" and "ae", because the ligatures do not appear on the AZERTY keyboard layout used in French-speaking countries. However this is nonstandard in formal and literary texts.
+
+French spelling, like English spelling, tends to preserve obsolete pronunciation rules. This is mainly due to extreme phonetic changes since the Old French period, without a corresponding change in spelling. Moreover, some conscious changes were made to restore Latin orthography (as with some English words such as "debt"):
+
+French is a morphophonemic language. While it contains 130 graphemes that denote only 36 phonemes, many of its spelling rules are likely due to a consistency in morphemic patterns such as adding suffixes and prefixes.[94] Many given spellings of common morphemes usually lead to a predictable sound. In particular, a given vowel combination or diacritic generally leads to one phoneme. However, there is not a one-to-one relation of a phoneme and a single related grapheme, which can be seen in how tomber and tombé both end with the /e/ phoneme.[95] Additionally, there are many variations in the pronunciation of consonants at the end of words, demonstrated by how the x in paix is not pronounced though at the end of Aix it is.
+
+As a result, it can be difficult to predict the spelling of a word based on the sound. Final consonants are generally silent, except when the following word begins with a vowel (see Liaison (French)). For example, the following words end in a vowel sound: pied, aller, les, finit, beaux. The same words followed by a vowel, however, may sound the consonants, as they do in these examples: beaux-arts, les amis, pied-à-terre.
+
+French writing, as with any language, is affected by the spoken language. In Old French, the plural for animal was animals. The /als/ sequence was unstable and was turned into a diphthong /aus/. This change was then reflected in the orthography: animaus. The us ending, very common in Latin, was then abbreviated by copyists (monks) by the letter x, resulting in a written form animax. As the French language further evolved, the pronunciation of au turned into /o/ so that the u was reestablished in orthography for consistency, resulting in modern French animaux (pronounced first /animos/ before the final /s/ was dropped in contemporary French). The same is true for cheval pluralized as chevaux and many others. In addition, castel pl. castels became château pl. châteaux.
+
+Some proposals exist to simplify the existing writing system, but they still fail to gather interest.[96][97][98][99]
+
+In 1990, a reform accepted some changes to French orthography. At the time the proposed changes were considered to be suggestions. In 2016, schoolbooks in France began to use the newer recommended spellings, with instruction to teachers that both old and new spellings be deemed correct.[100]
+
+French is a moderately inflected language. Nouns and most pronouns are inflected for number (singular or plural, though in most nouns the plural is pronounced the same as the singular even if spelled differently); adjectives, for number and gender (masculine or feminine) of their nouns; personal pronouns and a few other pronouns, for person, number, gender, and case; and verbs, for tense, aspect, mood, and the person and number of their subjects. Case is primarily marked using word order and prepositions, while certain verb features are marked using auxiliary verbs. According to the French lexicogrammatical system, French has a rank-scale hierarchy with clause as the top rank, which is followed by group rank, word rank, and morpheme rank. A French clause is made up of groups, groups are made up of words, and lastly, words are made up of morphemes.[101]
+
+French grammar shares several notable features with most other Romance languages, including
+
+Every French noun is either masculine or feminine. Because French nouns are not inflected for gender, a noun's form cannot specify its gender. For nouns regarding the living, their grammatical genders often correspond to that which they refer to. For example, a male teacher is a "enseignant" while a female teacher is a "enseignante". However, plural nouns that refer to a group that includes both masculine and feminine entities are always masculine. So a group of two male teachers would be "enseignants". A group of two male teachers and two female teachers would still be "enseignants". In many situations, and in the case of "enseignant", both the singular and plural form of a noun are pronounced identically. The article used for singular nouns is different from that used for plural nouns and the article provides a distinguishing factor between the two in speech. For example, the singular "le professeur" or "la professeur(e)" (the male or female teacher, professor) can be distinguished from the plural "les professeurs" because "le", "la", and "les" are all pronounced differently. There are some situations where both the feminine and masculine form of a noun are the same and the article provides the only difference. For example, "le dentiste" refers to a male dentist while "la dentiste" refers to a female dentist.
+
+The French language consists of both finite and non-finite moods. The finite moods include the indicative mood (indicatif), the subjunctive mood (subjonctif), the imperative mood (impératif), and the conditional mood (conditionnel). The non-finite moods include the infinitive mood (infinitif), the present participle (participe présent), and the past participle (participe passé).
+
+The indicative mood makes use of eight tense-aspect forms. These include the present (présent), the simple past (passé composé and passé simple), the past imperfective (imparfait), the pluperfect (plus-que-parfait), the simple future (futur simple), the future perfect (futur antérieur), and the past perfect (passé antérieur). Some forms are less commonly used today. In today's spoken French, the passé composé is used while the passé simple is reserved for formal situations or for literary purposes. Similarly, the plus-que-parfait is used for speaking rather than the older passé antérieur seen in literary works.
+
+Within the indicative mood, the passé composé, plus-que-parfait, futur antérieur, and passé antérieur all use auxiliary verbs in their forms.
+
+The subjunctive mood only includes four of the tense-aspect forms found in the indicative: present (présent), simple past (passé composé), past imperfective (imparfait), and pluperfect (plus-que-parfait).
+
+Within the subjunctive mood, the passé composé and plus-que-parfait use auxiliary verbs in their forms.
+
+The imperative is used in the present tense (with the exception of a few instances where it is used in the perfect tense). The imperative is used to give commands to you (tu), we/us (nous), and plural you (vous).
+
+The conditional makes use of the present (présent) and the past (passé).
+
+The passé uses auxiliary verbs in its forms.
+
+French uses both the active voice and the passive voice. The active voice is unmarked while the passive voice is formed by using a form of verb être ("to be") and the past participle.
+
+Example of the active voice:
+
+Example of the passive voice:
+
+French declarative word order is subject–verb–object although a pronoun object precedes the verb. Some types of sentences allow for or require different word orders, in particular inversion of the subject and verb like "Parlez-vous français?" when asking a question rather than just "Vous parlez français ?" Both questions mean the same thing; however, a rising inflection is always used on both of them whenever asking a question, especially on the second one. Specifically, the first translates into "Do you speak French?" while the second one is literally just "You speak French?" To avoid inversion while asking a question, 'Est-ce que' (literally 'is it that') may be placed in the beginning of the sentence. "Parlez-vous français ?" may become "Est-ce que vous parlez français ?" French also uses verb–object–subject (VOS) and object–subject–verb (OSV) word order. OSV word order is not used often and VOS is reserved for formal writings.[31]
+
+The majority of French words derive from Vulgar Latin or were constructed from Latin or Greek roots. In many cases a single etymological root appears in French in a "popular" or native form, inherited from Vulgar Latin, and a learned form, borrowed later from Classical Latin. The following pairs consist of a native noun and a learned adjective:
+
+However, a historical tendency to gallicise Latin roots can be identified, whereas English conversely leans towards a more direct incorporation of the Latin:
+
+There are also noun-noun and adjective-adjective pairs:
+
+It can be difficult to identify the Latin source of native French words, because in the evolution from Vulgar Latin, unstressed syllables were severely reduced and the remaining vowels and consonants underwent significant modifications.
+
+More recently the linguistic policy of the French language academies of France and Quebec has been to provide French equivalents to (mainly English) imported words, either by using existing vocabulary, extending its meaning or deriving a new word according to French morphological rules. The result is often two (or more) co-existing terms for describing the same phenomenon.
+
+Root languages of loanwords[102]
+
+It is estimated that 12% (4,200) of common French words found in a typical dictionary such as the Petit Larousse or Micro-Robert Plus (35,000 words) are of foreign origin (where Greek and Latin learned words are not seen as foreign). About 25% (1,054) of these foreign words come from English and are fairly recent borrowings. The others are some 707 words from Italian, 550 from ancient Germanic languages, 481 from other Gallo-Romance languages, 215 from Arabic, 164 from German, 160 from Celtic languages, 159 from Spanish, 153 from Dutch, 112 from Persian and Sanskrit, 101 from Native American languages, 89 from other Asian languages, 56 from other Afro-Asiatic languages, 55 from Slavic languages and Baltic languages, 10 from Basque and 144 (about 3%) from other languages.[102]
+
+One study analyzing the degree of differentiation of Romance languages in comparison to Latin estimated that among the languages analyzed French has the greatest distance from Latin.[103] Lexical similarity is 89% with Italian, 80% with Sardinian, 78% with Rhaeto-Romance, and 75% with Romanian, Spanish and Portuguese.[104][105][104]
+
+The French counting system is partially vigesimal: twenty (vingt) is used as a base number in the names of numbers from 70 to 99. The French word for 80 is quatre-vingts, literally "four twenties", and the word for 75 is soixante-quinze, literally "sixty-fifteen". This reform arose after the French Revolution to unify the counting systems (mostly vigesimal near the coast, because of Celtic (via Breton) and Viking influences. This system is comparable to the archaic English use of score, as in "fourscore and seven" (87), or "threescore and ten" (70).
+
+In Old French (during the Middle Ages), all numbers from 30 to 99 could be said in either base 10 or base 20, e.g. vint et doze (twenty and twelve) for 32, dous vinz et diz (two twenties and ten) for 50, uitante for 80, or nonante for 90.[106]
+
+Belgian French, Swiss French, Aostan French[107] and the French used in the Democratic Republic of the Congo, Rwanda and Burundi are different in this respect. In the French spoken in these places, 70 and 90 are septante and nonante. In Switzerland, depending on the local dialect, 80 can be quatre-vingts (Geneva, Neuchâtel, Jura) or huitante (Vaud, Valais, Fribourg). Octante had been used in Switzerland in the past, but is now considered archaic,[108] while in the Aosta Valley 80 is huitante.[107] In Belgium and in its former African colonies, however, quatre-vingts is universally used.
+
+French, like most European languages, uses a space to separate thousands.[109] The comma is used in French numbers as a decimal point, i.e. "2,5" instead of "2.5".
+
+Notes
+

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+Frankfurt am Main is a major city in Hesse, Germany.
+
+Frankfurt may also refer to:

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+
+
+Frankfurt (officially: Frankfurt am Main (German: [ˈfʁaŋkfʊʁt ʔam ˈmaɪn] (listen); Hessian: Frangford am Maa, lit. "Frank ford on the[a] Main")) is a metropolis and the largest city of the German state of Hesse. Its 753,056 (2018) inhabitants make it the fifth-largest city in Germany. On the River Main (a tributary of the Rhine), it forms a continuous conurbation with the neighbouring city of Offenbach am Main and its urban area has a population of 2.3 million.[2][4] The city is at the centre of the larger Rhine-Main Metropolitan Region, which has a population of 5.5 million[1] and is Germany's second-largest metropolitan region after the Rhine-Ruhr Region. Frankfurt's central business district lies about 90 km (56 mi) northwest of the geographic centre of the EU at Gadheim, Lower Franconia. Like France and Franconia, the city is named after the Franks. Frankfurt is the largest city in the Rhine Franconian dialect area.
+
+Frankfurt was a city state, the Free City of Frankfurt, for nearly five centuries and was one of the most important cities of the Holy Roman Empire, as a site of imperial coronations; it lost its sovereignty upon the collapse of the empire in 1806, regained it in 1815 and then lost it again in 1866, when it was annexed (though neutral) by the Kingdom of Prussia. It has been part of the state of Hesse since 1945. Frankfurt is culturally, ethnically and religiously diverse, with half of its population, and a majority of its young people, having a migration background. A quarter of the population consists of foreign nationals, including many expatriates.
+
+Frankfurt is a global hub for commerce, culture, education, tourism and transportation, and rated as an "alpha world city" according to GaWC. It is the site of many global and European corporate headquarters. Frankfurt Airport is among the world's busiest. Frankfurt is one of the major financial centres of the European continent, with the headquarters of the European Central Bank, Deutsche Bundesbank, Frankfurt Stock Exchange, Deutsche Bank, DZ Bank, KfW, Commerzbank, several cloud and fintech startups[5] and other institutes. Automotive, technology and research, services, consulting, media and creative industries complement the economic base. Frankfurt's DE-CIX is the world's largest internet exchange point. Messe Frankfurt is one of the world's largest trade fairs. Major fairs include the Music Fair and the Frankfurt Book Fair, the world's largest book fair.
+
+Frankfurt is home to influential educational institutions, including the Goethe University, the UAS, the FUMPA and graduate schools like the Frankfurt School of Finance & Management. Its renowned cultural venues include the concert hall Alte Oper, Europe's largest English theatre and many museums (e.g. the Museumsufer ensemble with Städel and Liebieghaus, Senckenberg Natural Museum, Goethe House and the Schirn art venue at the old town). Frankfurt's skyline is shaped by some of Europe's tallest skyscrapers. The city is also characterised by various green areas and parks, including the central Wallanlagen, the City Forest, two major botanical gardens (the Palmengarten and the University's Botanical Garden) and the Frankfurt Zoo. In electronic music, Frankfurt has been a pioneering city since the 1980s, with renowned DJs including Sven Väth, Marc Trauner, Scot Project, Kai Tracid, and the clubs Dorian Gray, U60311, Omen and Cocoon. In sports, the city is known as the home of the top tier football club Eintracht Frankfurt, the Löwen Frankfurt ice hockey team, the basketball club Frankfurt Skyliners, the Frankfurt Marathon and the venue of Ironman Germany. It was also one of the host cities of the 1974 and 2006 FIFA World Cups.
+
+Frankfurt is the largest financial centre in continental Europe. It is home to the European Central Bank, Deutsche Bundesbank, Frankfurt Stock Exchange and several large commercial banks.
+
+The Frankfurt Stock Exchange is one of the world's largest stock exchanges by market capitalization and accounts for more than 90 percent of the turnover in the German market.
+
+In 2010, 63 national and 152 international banks had their registered offices in Frankfurt, including Germany's major banks, notably Deutsche Bank, DZ Bank, KfW and Commerzbank, as well as 41 representative offices of international banks.[6]
+
+Frankfurt is considered a global city (alpha world city) as listed by the GaWC group's 2012 inventory.[7] Among global cities it was ranked 10th by the Global Power City Index 2011 and 11th by the Global City Competitiveness Index 2012. Among financial centres it was ranked 8th by the International Financial Centers Development Index 2013 and 9th in the 2013 Global Financial Centres Index.
+
+Its central location within Germany and Europe makes Frankfurt a major air, rail and road transport hub. Frankfurt Airport is one of the world's busiest international airports by passenger traffic and the main hub for Germany's flag carrier Lufthansa. Frankfurt Central Station is one of the largest rail stations in Europe and the busiest junction operated by Deutsche Bahn, the German national railway company, with 342 trains a day to domestic and European destinations.[8] Frankfurter Kreuz, the Autobahn interchange close to the airport, is the most heavily used interchange in the EU, used by 320,000 cars daily.[9] In 2011 human-resource-consulting firm Mercer ranked Frankfurt as seventh in its annual 'Quality of Living' survey of cities around the world.[10] According to The Economist cost-of-living survey, Frankfurt is Germany's most expensive city and the world's 10th most expensive.[11]
+
+Frankfurt has many high-rise buildings in the city centre, forming the Frankfurt skyline. It is one of the few cities in the European Union to have such a skyline, which is why Germans sometimes refer to Frankfurt as Mainhattan, a portmanteau of the local Main River and Manhattan. The other well known and obvious nickname is Bankfurt. Before World War II the city was globally noted for its unique old town with timber-framed buildings, the largest timber-framed old town in Europe. The Römer area was later rebuilt and is popular with visitors and for events such as Christmas markets. Other parts of the old town were reconstructed as part of the Dom-Römer Project from 2012 to 2018.
+
+Frankonovurd (in Old High German) or Vadum Francorum (in Latin) were the first names mentioned in written records from 794. It transformed to Frankenfort during the Middle Ages and then to Franckfort and Franckfurth in the modern era. According to historian David Gans, the city was named c. 146 AD by its builder, a Frankish king named Zuna, who ruled over the province then known as Sicambri. He hoped thereby to perpetuate the name of his lineage.[12] The name is derived from the Franconofurd of the Germanic tribe of the Franks; Furt (cf. English ford) where the river was shallow enough to be crossed on foot.
+
+By the 19th century, the name Frankfurt had been established as the official spelling. The older English spelling of Frankfort is now rarely seen in reference to Frankfurt am Main, although more than a dozen other towns and cities, mainly in the United States, use this spelling (e.g., Frankfort, Kentucky; Frankfort, New York; Frankfort, Illinois).
+
+The suffix am Main has been used regularly since the 14th century. In English, the city's full name of Frankfurt am Main means "Frankfurt on the Main" (pronounced like English mine or German mein). Frankfurt is located on an ancient ford (German: Furt) on the Main River. As a part of early Franconia, the inhabitants were the early Franks, thus the city's name reveals its legacy as "the ford of the Franks on the Main".[13]
+
+Among English speakers, the city is commonly known simply as Frankfurt, but Germans occasionally call it by its full name to distinguish it from the other (significantly smaller) German city of Frankfurt an der Oder in the Land of Brandenburg on the Polish border.
+
+The city district Bonames has a name probably dating back to Roman times, thought to be derived from bona me(n)sa (good table).
+
+The common abbreviations for the city, primarily used in railway services and on road signs, are Frankfurt (Main), Frankfurt (M), Frankfurt a. M., Frankfurt/Main or Frankfurt/M. The common abbreviation for the name of the city is "FFM". Also in use is "FRA", the IATA code for Frankfurt Airport.
+
+Roman settlements were established in the area of the Römer, probably in the first century. Nida (Heddernheim) was also a Roman civitas capital.
+
+Alemanni and Franks lived there, and by 794, Charlemagne presided over an imperial assembly and church synod, at which Franconofurd (alternative spellings end with -furt and -vurd) was first mentioned.
+
+Frankfurt was one of the most important cities in the Holy Roman Empire. From 855, the German kings and emperors were elected and crowned in Aachen. From 1562, the kings and emperors were crowned in Frankfurt, initiated for Maximilian II. This tradition ended in 1792, when Franz II was elected. His coronation was deliberately held on Bastille Day, 14 July, the anniversary of the storming of the Bastille. The elections and coronations took place in St. Bartholomäus Cathedral, known as the Kaiserdom (Emperor's Cathedral), or its predecessors.
+
+The Frankfurter Messe (Frankfurt Trade Fair) was first mentioned in 1150. In 1240, Emperor Friedrich II granted an imperial privilege to its visitors, meaning they would be protected by the empire. The fair became particularly important when similar fairs in French Beaucaire lost attraction around 1380. Book trade fairs began in 1478.
+
+In 1372, Frankfurt became a Reichsstadt (Imperial Free City), i.e., directly subordinate to the Holy Roman Emperor and not to a regional ruler or a local nobleman.
+
+In 1585, Frankfurt traders established a system of exchange rates for the various currencies that were circulating to prevent cheating and extortion. Therein lay the early roots for the Frankfurt Stock Exchange.
+
+Frankfurt managed to remain neutral during the Thirty Years' War, but suffered from the bubonic plague that refugees brought to the city. After the war, Frankfurt regained its wealth. In the late 1770s the theatre principal Abel Seyler was based in Frankfurt, and established the city's theatrical life.[14]
+
+Following the French Revolution, Frankfurt was occupied or bombarded several times by French troops. It remained a free city until the collapse of the Holy Roman Empire in 1805/6. In 1806, it became part of the principality of Aschaffenburg under the Fürstprimas (Prince-Primate), Karl Theodor Anton Maria von Dalberg. This meant that Frankfurt was incorporated into the confederation of the Rhine. In 1810, Dalberg adopted the title of a Grand Duke of Frankfurt. Napoleon intended to make his adopted son Eugène de Beauharnais, already Prince de Venise ("prince of Venice", a newly established primogeniture in Italy), Grand Duke of Frankfurt after Dalberg's death (since the latter as a Catholic bishop had no legitimate heirs). The Grand Duchy remained a short episode lasting from 1810 to 1813, when the military tide turned in favour of the Anglo-Prussian lead allies that overturned the Napoleonic order. Dalberg abdicated in favour of Eugène de Beauharnais, which of course was only a symbolic action, as the latter effectively never ruled after the ruin of the French armies and Frankfurt's takeover by the allies.
+
+After Napoleon's final defeat and abdication, the Congress of Vienna (1814–1815) dissolved the grand-duchy and Frankfurt became a fully sovereign city state with a republican form of government. Frankfurt entered the newly founded German Confederation (till 1866) as a free city, becoming the seat of its Bundestag, the confederal parliament where the nominally presiding Habsburg Emperor of Austria was represented by an Austrian "presidential envoy".
+
+After the ill-fated revolution of 1848, Frankfurt was the seat of the first democratically elected German parliament, the Frankfurt Parliament, which met in the Frankfurter Paulskirche (St. Paul's Church) and was opened on 18 May 1848. The institution failed in 1849 when the Prussian king, Frederick William IV, declared that he would not accept "a crown from the gutter". In the year of its existence, the assembly developed a common constitution for a unified Germany, with the Prussian king as its monarch.
+
+Frankfurt lost its independence after the Austro-Prussian War in 1866 when Prussia annexed several smaller states, among them the Free City of Frankfurt. The Prussian administration incorporated Frankfurt into its province of Hesse-Nassau. The Prussian occupation and annexation was perceived as a great injustice in Frankfurt, which retained its distinct western European, urban and cosmopolitan character. The formerly independent towns of Bornheim and Bockenheim were incorporated in 1890.
+
+In 1914, the citizens founded the University of Frankfurt, later named Goethe University Frankfurt. This marked the only civic foundation of a university in Germany; today it is one of Germany's largest.
+
+From 6 April to 17 May 1920, following military intervention to put down the Ruhr uprising, Frankfurt was occupied by French troops.[15] The French claimed that Articles 42 to 44 of the peace treaty of Versailles concerning the demilitarisation of the Rhineland had been broken.[16] In 1924, Ludwig Landmann became the first Jewish mayor of the city, and led a significant expansion during the following years. During the Nazi era, the synagogues of the city were destroyed.
+
+Frankfurt was severely bombed in World War II (1939–1945). About 5,500 residents were killed during the raids, and the once-famous medieval city centre, by that time the largest in Germany, was almost completely destroyed. It became a ground battlefield on 26 March 1945, when the Allied advance into Germany was forced to take the city in contested urban combat that included a river assault. The 5th Infantry Division and the 6th Armored Division of the United States Army captured Frankfurt after several days of intense fighting, and it was declared largely secure on 29 March 1945.[17]
+
+After the end of the war, Frankfurt became a part of the newly founded state of Hesse, consisting of the old Hesse-(Darmstadt) and the Prussian Hesse provinces. The city was part of the American Zone of Occupation of Germany. The Military Governor for the United States Zone (1945–1949) and the United States High Commissioner for Germany (HICOG) (1949–1952) had their headquarters in the IG Farben Building, intentionally left undamaged by the Allies' wartime bombardment.
+
+Frankfurt was the original choice for the provisional capital city of the newly founded state of West Germany in 1949. The city constructed a parliament building that was never used for its intended purpose (it housed the radio studios of Hessischer Rundfunk). In the end, Konrad Adenauer, the first postwar Chancellor, preferred the town of Bonn, for the most part because it was close to his hometown, but also because many other prominent politicians opposed the choice of Frankfurt out of concern that Frankfurt would be accepted as the permanent capital, thereby weakening the West German population's support for a reunification with East Germany and the eventual return of the capital to Berlin.
+
+Postwar reconstruction took place in a sometimes simple modern style, thus changing Frankfurt's architectural face. A few landmark buildings were reconstructed historically, albeit in a simplified manner (e.g., Römer, St. Paul's Church, and Goethe House). The collection of historically significant Cairo Genizah documents of the Municipal Library was destroyed by the bombing. According to Arabist and Genizah scholar S.D. Goitein, "not even handlists indicating its contents have survived."[18]
+
+The end of the war marked Frankfurt's comeback as Germany's leading financial centre, mainly because Berlin, now a city divided into four sectors, could no longer rival it. In 1948, the allies founded the Bank deutscher Länder, the forerunner of Deutsche Bundesbank. Following this decision, more financial institutions were re-established, e.g. Deutsche Bank and Dresdner Bank. In the 1950s, Frankfurt Stock Exchange regained its position as the country's leading stock exchange.
+
+Frankfurt also re-emerged as Germany's transportation centre and Frankfurt Airport became Europe's second-busiest airport behind London Heathrow Airport in 1961.
+
+During the 1970s, the city created one of Europe's most efficient underground transportation systems.[19] That system includes a suburban rail system (S-Bahn) linking outlying communities with the city centre, and a deep underground light rail system with smaller coaches (U-Bahn) also capable of travelling above ground on rails.
+
+In 1998, the European Central Bank was founded in Frankfurt, followed by the European Insurance and Occupational Pensions Authority and European Systemic Risk Board in 2011.
+
+Frankfurt is the largest city in the federated state of Hesse in the south-western part of Germany.
+
+Frankfurt is located on both sides of the Main River, south-east of the Taunus mountain range. The southern part of the city contains the Frankfurt City Forest, Germany's largest city forest. The city area is 248.31 km2 (95.87 sq mi) and extends over 23.4 km (14.54 mi) east to west and 23.3 km (14.48 mi) north to south. The city centre is north of the River Main in Altstadt district (the historical centre) and the surrounding Innenstadt district. The geographical centre is in Bockenheim district near Frankfurt West station.
+
+Frankfurt is the centre of the densely populated Frankfurt Rhine-Main Metropolitan Region with a population of 5.5 million. Other important cities in the region are Wiesbaden (capital of Hesse), Mainz (capital of Rhineland-Palatinate), Darmstadt, Offenbach am Main, Hanau, Aschaffenburg, Bad Homburg vor der Höhe, Rüsselsheim, Wetzlar and Marburg.
+
+The city is divided into 46 city districts (Stadtteile), which are in turn divided into 121 city boroughs (Stadtbezirke) and 448 electoral districts (Wahlbezirke). The 46 city districts combine into 16 area districts (Ortsbezirke), which each have a district committee and chairperson.
+
+The largest city district by population and area is Sachsenhausen, while the smallest is Altstadt, Frankfurt's historical center. Three larger city districts (Sachsenhausen, Westend and Nordend) are divided for administrative purposes into a northern (-Nord) and a southern (-Süd) part, respectively a western (-West) and an eastern (-Ost) part, but are generally considered as one city district (which is why often only 43 city districts are mentioned, even on the City's official website).[20]
+
+Some larger housing areas are often falsely called city districts, even by locals, like Nordweststadt (part of Niederursel, Heddernheim and Praunheim), Goldstein (part of Schwanheim), Riedberg (part of Kalbach-Riedberg) and Europaviertel (part of Gallus). The Bankenviertel (banking district), Frankfurt's financial district, is also not an administrative city district (it covers parts of the western Innenstadt district, the southern Westend district and the eastern Bahnhofsviertel district).
+
+Many city districts are incorporated suburbs (Vororte), or were previously independent cities, such as Höchst. Some like Nordend and Westend arose during the rapid growth of the city in the Gründerzeit following the Unification of Germany, while others were formed from territory which previously belonged to other city district(s), such as Dornbusch and Riederwald.
+
+Until the year 1877 the city's territory consisted of the present-day inner-city districts of Altstadt, Innenstadt, Bahnhofsviertel, Gutleutviertel, Gallus, Westend, Nordend, Ostend and Sachsenhausen.
+
+Bornheim was part of an administrative district called Landkreis Frankfurt, before becoming part of the city on 1 January 1877, followed by Bockenheim on 1 April 1895. Seckbach, Niederrad and Oberrad followed on 1 July 1900. The Landkreis Frankfurt was finally dispersed on 1 April 1910, and therefore Berkersheim, Bonames, Eckenheim, Eschersheim, Ginnheim, Hausen, Heddernheim, Niederursel, Praunheim, Preungesheim and Rödelheim joined the City. In the same year a new city district, Riederwald, was created on territory that had formerly belonged to Seckbach and Ostend.
+
+On 1 April 1928 the City of Höchst became part of Frankfurt, as well as its city districts Sindlingen, Unterliederbach and Zeilsheim. Simultaneously the Landkreis Höchst was dispersed with its member cities either joining Frankfurt (Fechenheim, Griesheim, Nied, Schwanheim, Sossenheim) or joining the newly established Landkreis of Main-Taunus-Kreis.
+
+Dornbusch became a city district in 1946. It was created on territory that had formerly belonged to Eckenheim and Ginnheim.
+
+On 1 August 1972 Hesse's smaller suburbs of Harheim, Kalbach, Nieder-Erlenbach, and Nieder-Eschbach became districts while other neighbouring suburbs chose to join the Main-Taunus-Kreis, the Landkreis Offenbach, the Kreis Groß-Gerau, the Hochtaunuskreis, the Main-Kinzig-Kreis or the Wetteraukreis.
+
+Bergen-Enkheim was the last suburb to become part of Frankfurt on 1 January 1977.
+
+Flughafen became an official city district in 1979. It covers the area of Frankfurt Airport that had belonged to Sachsenhausen and the neighbouring city of Mörfelden-Walldorf.
+
+Frankfurt's youngest city district is Frankfurter Berg. It was part of Bonames until 1996.
+
+Kalbach was officially renamed Kalbach-Riedberg in 2006 because of the large residential housing development in the area known as Riedberg.
+
+To the west Frankfurt borders the administrative district (Landkreis) of Main-Taunus-Kreis with towns such as Hattersheim am Main, Kriftel, Hofheim am Taunus, Kelkheim, Liederbach am Taunus, Sulzbach, Schwalbach am Taunus and Eschborn; to the northwest the Hochtaunuskreis with Steinbach, Oberursel (Taunus) and Bad Homburg vor der Höhe; to the north the Wetteraukreis with Karben and Bad Vilbel; to the northeast the Main-Kinzig-Kreis with Niederdorfelden and Maintal; to the southeast the city of Offenbach am Main; to the south the Kreis Offenbach with Neu-Isenburg and to the southwest the Kreis Groß-Gerau with Mörfelden-Walldorf, Rüsselsheim and Kelsterbach.
+
+Together with these towns (and some larger nearby towns, e.g., Hanau, Rodgau, Dreieich, Langen) Frankfurt forms a contiguous built-up urban area called Stadtregion Frankfurt which is not an official administrative district. The urban area had an estimated population of 2.3 million in 2010 and is therefore the 13th largest urban area in the European Union.
+
+Frankfurt has a temperate-oceanic climate (Köppen: Cfb). Its average annual temperature is 10.6 °C (51.1 °F), with monthly mean temperatures ranging from 1.6 °C (34.9 °F) in January to 20.0 °C (68.0 °F) in July.
+
+With a population of 732,688 (2015) within its administrative boundaries[24] and of 2,300,000 in the actual urban area,[4] Frankfurt is the fifth largest city in Germany after Berlin, Hamburg, Munich and Cologne. 
+Central Frankfurt has been a Großstadt (a city with at least 100,000 residents by definition) since 1875. With 414,576 residents in 1910, it was the ninth largest city in Germany and the number of inhabitants grew to 553,464 before World War II. After the war, at the end of the year 1945, the number had dropped to 358,000. In the following years, the population grew again and reached an all-time-high of 691,257 in 1963. It dropped again to 592,411 in 1986 but has increased since then. According to the demographic forecasts for central Frankfurt, the city will have a population up to 825,000 within its administrative boundaries in 2020 and more than 2.5 million inhabitants in its urban area.
+
+During the 1970s, the state government of Hesse wanted to include the entire urban area into its administrative boundaries. This would have made Frankfurt officially the second largest city in Germany after Berlin with up to 3 million inhabitants.[25] However, because local authorities did not agree the administrative territory is still much smaller than its actual urban area.
+
+According to data from the city register of residents, 51.2% of the population had a migration background as of 2015, which means that a person or at least one or both of their parents was born with foreign citizenship. For the first time, a majority of the city residents had an at least part non-German background.[28] Moreover, three of four children in the city under the age of six had immigrant backgrounds.[29] and 27.7% of residents had a foreign citizenship.[30]
+
+According to statistics, 46.7% of immigrants in Frankfurt come from other countries in The European Union, 24.5% of immigrants in Frankfurt come from European countries that are not part of the EU, 15.7% of immigrants in Frankfurt come from Asia (including Western Asia and South Asia), 7.3% of immigrants in Frankfurt come from Africa, 3.4% of immigrants in Frankfurt come from North America (Including the Caribbean and Central America), 0.2% of immigrants in Frankfurt come from Australia and Zealandia, 2.3% of immigrants in Frankfurt come from South America and 1.1% of immigrants in Frankfurt come from The Pacific Island Nations. Because of this, the city is often considered to be a multicultural city and has been compared to New York City and London.
+
+Frankfurt was historically a Protestant-dominated city. However, during the 19th century an increasing number of Catholics moved there. The Jewish community has a history dating back to Medieval times and has always ranked among the largest in Germany. Two synagogues operate there. Due to the growing immigration of people from Muslim countries beginning in the 1960s, Frankfurt has a large Muslim community. The Ahmadiyya Noor Mosque, constructed in 1959, is the city's largest mosque and the third largest in Germany.[31]
+
+As of 2013[update], the largest Christian denominations were Catholicism (22.7% of the population) and Protestantism, especially Lutheranism (19.4%).[32] Estimations put the share of Muslim inhabitants at approximately 12% (2006).[33] According to calculations based on census data for 21 countries of origin, the number of Muslim migrants in Frankfurt amounted to about 84,000 in 2011, making up 12.6 percent of the population.[34] A large part of them was from Turkey and Morocco. Over 7,000 inhabitants were affiliated with the Jewish community, amounting to approximately 1% of the population.[35]
+
+Frankfurt is one of five independent district-free cities (kreisfreie Städte) in Hesse, which means that it does not form part of another general-purpose local government entity, in this case it is not part of a Landkreis. The other four cities are the second to fifth largest cities in Hesse: Wiesbaden, Kassel, Darmstadt and Offenbach am Main. A kreisfreie Stadt has territorial sovereignty within its defined city limits.
+
+In 1995 Petra Roth of the Christian Democratic Union (CDU) became Lord Mayor (Oberbürgermeisterin), Frankfurt's municipal leader. In 2012, Peter Feldmann (SPD) succeeded Roth as Lord Mayor. The CDU and the Alliance '90/The Greens (Bündnis '90/Die Grünen) formed the government.
+
+Frankfurt is twinned with:
+
+
+
+
+
+Partnerships and city friendships are a weaker form of cooperation than the sister city relationship, acting more like a fixed-term cooperation or limited to certain projects. Frankfurt has partnerships with the following cities:
+
+Römer
+
+Römer, the German word for Roman, is a complex of nine houses that form the Frankfurt city hall (Rathaus). The houses were acquired by the city council in 1405 from a wealthy merchant family. The middle house became the city hall and was later connected with its neighbours. The Kaisersaal ("Emperor's Hall") is located on the upper floor and is where the newly crowned emperors held their banquets. The Römer was partially destroyed in World War II and later rebuilt. The surrounding square, the Römerberg, is named after the city hall.
+
+The former Altstadt (old town) quarter between the Römer and the Frankfurt Cathedral was redeveloped as the Dom-Römer Quarter from 2012 to 2018, including 15 reconstructions of historical buildings that were destroyed during World War II.
+
+Frankfurt Cathedral
+
+Frankfurt Cathedral (Frankfurter Dom) is not a cathedral, but the main Catholic church, dedicated to St. Bartholomew. The Gothic building was constructed in the 14th and 15th centuries on the foundation of an earlier church from the Merovingian time. From 1356 onwards, kings of the Holy Roman Empire were elected in this church, and from 1562 to 1792, Roman-German emperors were crowned there.
+
+Since the 18th century, St. Bartholomew's has been called Dom, although it was never a bishop's seat. In 1867 it was destroyed by fire and rebuilt in its present style. It was again partially destroyed in World War II and rebuilt in the 1950s. Its height is 95 meters. The cathedral tower has a viewing platform open to the public at a height of 66 meters, accessed through a narrow spiral staircase with 386 steps.
+
+St. Paul's Church
+
+St. Paul's Church (Paulskirche) is a national historic monument in Germany because it was the seat of the first democratically elected parliament in 1848. It was established in 1789 as a Protestant church, but was not completed until 1833. Its importance has its roots in the Frankfurt Parliament, which met in the church during the revolutionary years of 1848/49 in order to write a constitution for a united Germany. The attempt failed because the monarchs of Prussia and Austria did not want to lose power. In 1849 Prussian troops ended the democratic experiment by force and the parliament dissolved. Afterwards, the building was used for church services again.
+
+St. Paul's was partially destroyed in World War II, particularly its interior, which now has a modern appearance. It was quickly and symbolically rebuilt after the war; today it is used mainly for exhibitions and events.
+
+Archäologischer Garten Frankfurt
+
+The Archaeological Garden contains small parts of the oldest recovered buildings: an ancient Roman settlement and the Frankfurt Royal Palace (Kaiserpfalz Frankfurt) from the 6th century. The garden is located between the Römerberg and the Cathedral. It was discovered after World War II when the area was heavily bombed and later partly rebuilt. The remains were preserved and are now open to the public. There are plans underway to construct a building on top of the garden but anyhow it is decided that the garden will stay open to the public.
+
+Haus Wertheim
+
+Wertheim House is the only timbered house in the Altstadt district that survived the heavy bombings of World War II undamaged. It is located on the Römerberg next to the Historical Museum.
+
+Saalhof
+
+The Saalhof is the oldest conserved building in the Altstadt district and dates to the 12th century. It was used as an exhibition hall by Dutch clothiers when trade fairs were held during the 14th and 15th century. The Saalhof was partly destroyed in World War II and later rebuilt. Today it serves as a part of the Historical Museum.
+
+Eiserner Steg
+
+The Eiserner Steg (Iron Bridge) is a pedestrian-only bridge across the Main that connects Römerberg and Sachsenhausen. It was built in 1868 and was the second bridge to cross the river. After World War II, when it was blown up by the Wehrmacht, it was quickly rebuilt in 1946. Today some 10,000 people cross the bridge on a daily basis.
+
+Alte Oper
+
+The Alte Oper is a former opera house, hence the name "Old Opera". The opera house was built in 1880 by architect Richard Lucae. It was one of the major opera houses in Germany until it was heavily damaged in World War II. Until the late 1970s, it was a ruin, nicknamed "Germany's most beautiful ruin". Former Frankfurt Lord Mayor Rudi Arndt called for blowing it up in the 1960s, which earned him the nickname "Dynamite-Rudi". (Later on, Arndt said he never had meant his suggestion seriously.)
+
+Public pressure led to its refurbishment and reopening in 1981. Today, it functions as a famous concert hall, while operas are performed at the "new" Frankfurt Opera. The inscription on the frieze of the Alte Oper says: "Dem Wahren, Schönen, Guten" ("To the true, the beautiful, the good").
+
+Eschenheimer Turm
+
+The Eschenheim Tower (Eschenheimer Turm) was erected at the beginning of the 15th century and served as a city gate as part of late-medieval fortifications. It is the oldest and most unaltered building in the Innenstadt district.
+
+St. Catherine's Church
+
+St. Catherine's Church (Katharinenkirche) is the largest Protestant church, dedicated to Catherine of Alexandria, a martyred early Christian saint. It is located in the city centre at the entrance to the Zeil, the central pedestrian shopping street.
+
+Hauptwache
+
+Although today Hauptwache is mostly associated with the inner-city underground train station of the same name, the name originates from a baroque building on the square above the station. The Hauptwache building was constructed in 1730 and was used as a prison, therefore the name that translates as "main guard-house". Today the square surrounding the building is also called "Hauptwache" (formal: An der Hauptwache). It is situated in the city centre opposite to St. Catherine's Church and houses a famous café.
+
+Central Station
+
+Frankfurt Central Station (Frankfurt Hauptbahnhof), which opened in 1888, was built as the central train station for Frankfurt to replace three smaller train stations in the city centre and to boost the needed capacity for travellers. It was constructed as a terminus station and was the largest train station in Europe by floor area until 1915 when Leipzig Central Station was opened. Its three main halls were constructed in a neorenaissance-style, while the later enlargement with two outer halls in 1924 was constructed in neoclassic-style.
+
+Frankfurter Hof
+
+The Frankfurter Hof is a landmarked hotel in the city centre at Kaiserplatz, built from 1872 to 1876. It is part of Steigenberger Hotels group and is considered the city's most prestigious.
+
+St. Leonhard
+
+St. Leonhard, on the Main close to the bridge Eiserner Steg, is a Catholic late Gothic hall church, derived from a Romanesque style basilica beginning in 1425. It is the only one of nine churches in the Old Town that survived World War II almost undamaged. The parish serves the English-speaking community. The church has been under restoration since 2011.
+
+Frankfurt is one of the few European cities with a significant number of skyscrapers, (buildings at least 150 m (492.13 ft) tall). It hosts 17 out of Germany's 18 skyscrapers. Most skyscrapers and high-rise office buildings are located in the financial district (Bankenviertel) near the city centre, around the trade fair premises (Europaviertel) and at Mainzer Landstraße between Opernplatz and Platz der Republik, which connects the two areas.
+
+The 17 skyscrapers are:
+
+Other high-rise buildings include:
+
+For centuries, St. Bartholomeus's Cathedral was the tallest structure. The first building to exceed the 95-metre-high cathedral was not an office building but a grain silo, the 120-metre-high (390 ft) Henninger Turm, built from 1959 to 1961.
+
+The first high-rise building boom came in the 1970s when Westend Gate (then called Plaza Büro Center) and Silberturm were constructed and became the tallest buildings in Germany with a height of 159.3 metres and 166.3 metres, respectively. Around the same time, Frankfurter Büro Center and City-Haus (142.4 metres and 142.1 metres) were constructed at Mainzer Landstraße and Eurotower (148.0 metres) and Garden Tower (127.0 metres; then called Helaba-Hochhaus) were constructed in the financial district.
+
+None of the buildings constructed during the 1980s surpassed Silberturm. The most famous buildings from this decade are the Deutsche Bank Twin Towers at Taunusanlage, both 155.0 metres tall.
+
+The 1990s featured a second wave. Messeturm, built on the trade fair site, reached a height of 256.5 metres and became the tallest building in Europe by 1991. It was overtaken by the 259-metre-high (850 ft) Commerzbank Tower in 1997. Other tall buildings from this decade are Westendstrasse 1 (208.0 metres), Main Tower (200.0 metres) and Trianon (186.0 metres).
+
+In 21st-century Frankfurt, more high-rise buildings and skyscrapers (e.g., Skyper, Opernturm, Tower 185, Seat of the European Central Bank, Taunusturm) emerged, but none have surpassed Commerzbank Tower.
+
+With a large forest, many parks, the Main riverbanks and the two botanical gardens, Frankfurt is considered a "green city": More than 50 percent of the area within the city limits are protected green areas.[42]
+
+With more than 30 museums, Frankfurt has one of the largest variety of museums in Europe. 20 museums are part of the Museumsufer, located on the front row of both sides of the Main riverbank or nearby, which was created on an initiative by cultural politician Hilmar Hoffmann.
+
+Ten museums are located on the southern riverbank in Sachsenhausen between the Eiserner Steg and the Friedensbrücke. The street itself, Schaumainkai, is partially closed to traffic on Saturdays for Frankfurt's largest flea market.
+
+Two museums are located on the northern riverbank:
+
+Not directly located on the northern riverbank in the Altstadt district are:
+
+Another important museum is located in the Westend district:
+
+Other museums are the Dialogmuseum (Dialogue Museum) in the Ostend district, Eintracht Frankfurt Museum at Commerzbank-Arena, Explora Museum+Wissenschaft+Technik (Explora Museum of Science and Engineering) in the Nordend district, the Frankfurter Feldbahnmuseum (Light Railway Museum Frankfurt) in the Gallus district, the Verkehrsmuseum Frankfurt (Transport Museum Frankfurt) in the Schwanheim district, the Hammer Museum in the Bahnhofsviertel district and the Geldmuseum der Deutschen Bundesbank (Money Museum of the German Federal Bank) in the Ginnheim district.
+
+Eurodance and Trance music originated in Frankfurt. In 1989 German producers Michael Münzing and Luca Anzilotti (under the pseudonyms Benito Benites and John "Virgo" Garrett III) formed the Snap! project. Snap! songs combined Rap and Soul vocals adding rhythm by using computer technology and mixing electronic sounds, bass and drums. By doing so a new genre was born: Eurodance.[43] In the early 1990s, DJs including Sven Väth and DJ DAG (of Dance 2 Trance) first played a harder, deeper style of acid house that became popular worldwide over the next decade as Trance music. Some of the early and most influential Eurodance, Trance and Techno acts, e.g., La Bouche, Jam and Spoon, Magic Affair, Culture Beat, Snap!, Dance 2 Trance, Oliver Lieb and Hardfloor, and record labels such as Harthouse and Eye Q, were based in the city in the early 1990s.
+
+Frankfurt is home to two major botanical gardens.
+
+Frankfurt offers a variety of restaurants, bars, pubs and clubs. Clubs concentrate in and around the city centre and in the Ostend district, mainly close to Hanauer Landstraße. Restaurants, bars and pubs concentrate in Sachsenhausen, Nordend, Bornheim and Bockenheim.
+
+One of the main venues of the early Trance music sound was the Omen nightclub (closed 1998). Another popular disco club of the 1980-1990s and a hotspot for Techno/Trance music was the Dorian Gray, located within Terminal 1 at Frankfurt Airport. Because of the location at the airport the club had no restrictions regarding opening hours. The club had to close at the end of 2000 because of stricter fire safety regulations. Also notable for its extraordinary design was Coocoon Club in Fechenheim which opened in 2004 was and voted best techno club of the year by music magazines "Groove" and "Raveline" in 2004, 2005, 2006 and 2007. It closed in 2012.[45]
+
+The city can be accessed from around the world via Frankfurt Airport (Flughafen Frankfurt am Main) located 12 km (7 mi) southwest of the city centre. The airport has four runways and serves 265 non-stop destinations. Run by transport company Fraport it ranks among the world's busiest airports by passenger traffic and is the busiest airport by cargo traffic in Europe. The airport also serves as a hub for Condor and as the main hub for German flag carrier Lufthansa. It is the busiest airport in Europe in terms of cargo traffic, and the fourth busiest in Europe in terms of passenger traffic behind London Heathrow Airport, Paris Charles de Gaulle Airport and Amsterdam Airport Schiphol. Passenger traffic at Frankfurt Airport in 2018 was 69,510,269 passengers.
+
+A third terminal is being constructed (planned to open in 2023). The third terminal will increase the capacity of the airport to over 90 million passengers per year.[49]
+
+The airport can be reached by car or bus and has two railway stations, one for regional and one for long-distance traffic. The S-Bahn lines S8 and S9 (direction Offenbach Ost or Hanau Hbf) departing at the regional station take 10–15 minutes from the airport to Frankfurt Central Station and onwards to the city centre (Hauptwache station), the IC and ICE trains departing at the long-distance station take 10 minutes to Frankfurt Central Station.
+
+Despite the name, Frankfurt Hahn Airport (Flughafen Frankfurt-Hahn) is situated approximately 120 km (75 mi) from the city in Lautzenhausen (Rhineland-Palatinate). Hahn Airport is a major base for low-cost carrier Ryanair. This airport can only be reached by car or bus. An hourly bus service runs from Frankfurt Central Station, taking just over 2 hours [50]. Passenger traffic at Hahn Airport in 2010 was 3.5 million.
+
+Frankfurt Egelsbach Airport (Flugplatz Frankfurt-Egelsbach) is a busy general aviation airport located south-east of Frankfurt Airport, near Egelsbach.
+
+Frankfurt is a traffic hub for the German motorway (Autobahn) system. The Frankfurter Kreuz is an Autobahn interchange close to the airport, where the Bundesautobahn 3 (A3), Cologne to Würzburg, and the Bundesautobahn 5 (A5), Basel to Hanover, meet. With approximately 320,000 cars passing through it every day it is Europe's most heavily used interchange. The Bundesautobahn 66 (A66) connects Frankfurt with Wiesbaden in the west and Fulda in the east. The Bundesautobahn 661 (A661) is mainly a commuter motorway which starts in the south (Egelsbach), runs through the eastern part and ends in the north (Oberursel). The Bundesautobahn 648 (A648) is a very short motorway in the western part which primarily serves as a fast connection between the A 66 and the Frankfurt Trade Fair. The A5 in the west, the A3 in the south and the A661 in the north-east form a ring road around the inner city districts and define a Low-emission zone (Umweltzone; established in 2008), meaning that vehicles have to meet certain emission criteria to enter the zone.
+
+The streets of central Frankfurt are usually congested with cars during rush hour. Some areas, especially around the shopping streets Zeil, Goethestraße and Freßgass, are pedestrian-only streets. Car parks are located throughout the city and especially in the city centre.
+
+Frankfurt Central Station (Frankfurt Hauptbahnhof, often abbreviated as Frankfurt (Main) Hbf or F-Hbf) is the largest railway station in Germany by railway traffic. By daily passenger volume, it ranks second together with Munich Central Station (350,000 each) after Hamburg Central Station (450,000). It is located between the Gallus, the Gutleutviertel and the Bahnhofsviertel district, not far away from the trade fair and the financial district. It serves as a major hub for long-distance trains (InterCity, ICE) and regional trains as well as for Frankfurt's public transport system. It is a stop for most of ICE high speed lines, making it Germany's most important ICE station. ICE Trains to London via the Channel Tunnel were planned for 2013.[51] All Rhine-Main S-Bahn lines, two U-Bahn lines (U4, U5), several tram and bus lines stop there. Regional and local trains are integrated in the Public transport system Rhein-Main-Verkehrsverbund (RMV), the second largest integrated public transport systems in the world, after Verkehrsverbund Berlin-Brandenburg.
+
+Frankfurt Airport can be accessed by two railway stations: Frankfurt Airport long-distance station (Frankfurt Flughafen Fernbahnhof) is only for long-distance traffic and connects the airport to the main rail network, with most of the ICE services using the Cologne-Frankfurt high-speed rail line. The long-distance station is located outside the actual airport ground but has a connecting bridge for pedestrians to Terminal 1, concourse B. Frankfurt Airport regional station (Frankfurt Flughafen Regionalbahnhof) is for local S-Bahn trains (lines S8, S9) and regional trains. The regional station is located within Terminal 1, concourse B.
+
+Frankfurt's third long-distance station is Frankfurt South station (Frankfurt Südbahnhof, often abbreviated as Frankfurt (Main) Süd or F-Süd), located in Sachsenhausen. It is an important destination for local trains and trams (lines 14 to 16, 19) and the terminal stop for four U-Bahn lines (U1, U2, U3, U8) and four S-Bahn lines (S3, S4, S5, S6).
+
+The Frankfurt Trade Fair offers two railway stations: Messe station is for local S-Bahn trains (lines S3-S6) and is located at the centre of the trade fair premises while Festhalle/Messe station is served by U-Bahn line U4 and is located at the north-east corner of the premises.
+
+Two other major railway stations in the city centre are Konstablerwache and Hauptwache, located on each end of the Zeil. They are the main stations to change from east-to-west-bound S-Bahn trains to north-to-south-bound U-Bahn trains. Konstablerwache station is the second-busiest railway station regarding daily passenger volume (191,000) after the central station. The third-busiest railway station is Hauptwache station (181,000).[citation needed][52]
+
+There are three stations for intercity bus services in Frankfurt: one at the south side of the Central Station, one at the Terminal 2 of the airport and another one at Stephanstraße.[53]
+
+The city has two rapid transit systems: the U-Bahn and the S-Bahn, as well as an above-ground tram system. Information about the U- and S-Bahn can be found on the website of the RMV.[54]
+
+Nine S-Bahn lines (S1 to S9) connect Frankfurt with the densely populated Rhine Main Region. Most routes have at least 15-minute service during the day, either by one line running every 15 minutes, or by two lines servicing one route at a 30-minute interval. All lines, except line S7, run through the Frankfurt city tunnel and serve the stations Ostendstraße, Konstablerwache, Hauptwache, Taunusanlage and Frankfurt Central Station. When leaving the city the S-Bahn travels above ground. It provides access to the trade fair (S3, S4, S5, S6), the airport (S8, S9), the stadium (S7, S8, S9) and nearby cities such as Wiesbaden, Mainz, Darmstadt, Rüsselsheim, Hanau, Offenbach am Main, Oberursel, Bad Homburg, Kronberg, Friedberg and smaller towns that are on the way.
+The S8/S9 runs 24/7.
+
+The U-Bahn has nine lines (U1 to U9) serving Frankfurt and the larger suburbs of Bad Homburg and Oberursel in the north. The trains that run on the U-Bahn are in fact light rail (Stadtbahn) as many lines travel along a track in the middle of the street instead of underground further from the city centre. The minimum service interval is 2.5 minutes, although the usual pattern is that each line runs at 7.5 to 10-minute intervals, which produce between 3 and 5-minute intervals on city centre tracks shared by more than one line.
+
+Frankfurt has ten tram lines (11, 12, 14 to 21), with trams arriving usually every 10 minutes. Many sections are served by two lines, combining to run at 5-minute intervals during rush-hour. Trams only run above ground and serve more stops than the U-Bahn or the S-Bahn.
+
+A number of bus lines complete the Frankfurt public transport system. Night buses replace U-Bahn and tram services between 1:30 am and 3:30 am.[55] The central junction for the night bus service is Konstablerwache in the city centre, where all night bus lines start and end.
+
+Taxicabs can usually be found outside the major S-Bahn and U-Bahn stations, at the central station, the south station, the airport, the trade fair and in the crowded inner-city shopping streets. The common way to obtain a taxi is to either call a taxi operator or to go to a taxi rank. However, although not the norm, one can hail a passing taxi on the street.
+
+Uber ceased operations in Frankfurt on 9 November 2015 after operating in the city for 18 months.[56]
+
+Deutsche Bahn makes bicycles available for hire through their Call a Bike service. The bicycles are stationed all over the city, including at selected railway stations. They can easily be spotted because of their eye-catching silver-red colour. To rent a specific bike, riders either call a service number to get an unlock code or reserve the bike via the smartphone application. To return the bike, the rider locks it within a designated return area (and calls the service number, if not booked via the app).[57]
+
+Nextbike also makes bicycles available for hire in Frankfurt. They are stationed all over the city. These can be spotted with their blue color scheme.
+
+Cycle rickshaws (velotaxis), a type of tricycle designed to carry passengers in addition to the driver, are also available. These are allowed to operate in pedestrian-only areas and are therefore practical for sightseeing.
+
+Frankfurt has a network of cycle routes. Many long-distance bike routes into the city have cycle tracks that are separate from motor vehicle traffic. A number of roads in the city centre are "bicycle streets" where the cyclist has the right of way and where motorised vehicles are only allowed access if they do not disrupt the cycle users. In addition, cyclists are allowed to ride many cramped one-way streets in both directions. As of 2015[update], 15 percent of citizens used bicycles.[58]
+
+Frankfurt is one of the world's most important financial centres and Germany's financial capital, followed by Munich. Frankfurt was ranked 8th at the International Financial Centers Development Index (2013), 8th at the Worldwide Centres of Commerce Index (2008), 9th at the Global Financial Centres Index (September 2013),[59] 10th at the Global Power City Index (2011), 11th at the Global City Competitiveness Index (2012), 12th at the Innovation Cities Index (2011),[60] 14th at the World City Survey (2011) and 23rd at the Global Cities Index (2012).[61]
+
+The city's importance as a financial centre has risen since the eurozone crisis. Indications are the establishment of two institutions of the European System of Financial Supervisors (European Insurance and Occupational Pensions Authority and European Systemic Risk Board) in 2011 and the Single Supervisory Mechanism by which the European Central Bank was to assume responsibility for specific supervisory tasks related to the financial stability of the biggest and most important Eurozone banks.
+
+According to an annual study by Cushman & Wakefield, the European Cities Monitor (2010), Frankfurt has been one of the top three cities for international companies in Europe, after London and Paris, since the survey started in 1990.[62] It is the only German city considered to be an alpha world city (category 3) as listed by the Loughborough University group's 2010 inventory,[63] which was a promotion from the group's 2008 inventory when it was ranked as an alpha minus world city (category 4).[64]
+
+With over 922 jobs per 1,000 inhabitants, Frankfurt has the highest concentration of jobs in Germany. On work days and Saturdays one million people commute from all over the Rhein-Main-Area.
+
+The city is expected to benefit from international banks relocating jobs from London to Frankfurt as a result of Brexit to retain access to the EU market.[65][66] Thus far, Morgan Stanley, Citigroup Inc., Standard Chartered Plc and Nomura Holdings Inc. announced they would move their EU headquarters to Frankfurt.[66]
+
+Frankfurt is home to two important central banks: the German Bundesbank and the European Central Bank (ECB).[67]
+
+The European Central Bank (Europäische Zentralbank) is one of the world's most important central banks. The ECB sets monetary policy for the Eurozone, consisting of 19 European Union member states that have adopted the Euro (€) as their common currency. From 1998 the ECB Headquarters have been located in Frankfurt, first in the Eurotower at Willy-Brandt-Platz and in two other nearby high-rises. The new Seat of the European Central Bank in the Ostend district, consisting of the former wholesale market hall (Großmarkthalle) and a newly built 185-metre skyscraper, was completed in late 2014. The new building complex was designed to accommodate up to 2,300 ECB personnel. The location is a few kilometres away from the city centre and borders an industrial area as well as the Osthafen (East Harbour), It was primarily chosen because of its large premises which allows the ECB to install security arrangements without high fences.
+
+The city honours the importance of the ECB by officially using the slogan "The City of the Euro" since 1998.
+
+The Deutsche Bundesbank (German Federal Bank), located in Ginnheim, was established in 1957 as the central bank for the Federal Republic of Germany. Until the euro (€) was introduced in 1999, the Deutsche Bundesbank was responsible for the monetary policy of Germany and for the German currency, the Deutsche Mark (DM). The Bundesbank was greatly respected for its control of inflation through the second half of the 20th century. Today the Bundesbank is an integral part of the European System of Central Banks (ESCB) which is formed by all 28 European Union member states.
+
+In 2010, 63 national and 152 international banks had a registered office, including the headquarters of the major German banks, as well as 41 offices of international banks.[6] Frankfurt is therefore known as Bankenstadt ("City of the banks") and nicknamed "Mainhattan" (a portmanteau of the local Main river and Manhattan in New York City) or "Bankfurt". 73,200 people were employed at banks in 2010.
+
+Other major German banks include Frankfurter Volksbank, the second-largest Volksbank in Germany, Frankfurter Sparkasse and old-established private banks such as Bankhaus Metzler, Hauck & Aufhäuser and Delbrück Bethmann Maffei.
+
+Many international banks have a registered or a representative office, e.g., Credit Suisse, UBS, Bank of America, Morgan Stanley, Goldman Sachs, Merrill Lynch, JPMorgan Chase & Co., Bank of China, Banco do Brasil, Itaú Unibanco Société Générale, BNP Paribas, SEB, Royal Bank of Scotland and Barclays.
+
+The Frankfurt Stock Exchange (Frankfurter Wertpapierbörse) began in the 9th century. By the 16th century Frankfurt had developed into an important European hub for trade fairs and financial services. Today the Frankfurt Stock Exchange is by far the largest in Germany, with a turnover of more than 90 percent of the German stock market and is the third-largest in Europe after the London Stock Exchange and the European branch of the NYSE Euronext. The most important stock market index is the DAX, the index of the 30 largest German business companies listed at the stock exchange. The stock exchange is owned and operated by Deutsche Börse, which is itself listed in the DAX. Deutsche Börse also owns the European futures exchange Eurex and clearing company Clearstream. Trading takes place exclusively via the Xetra trading system, with redundant floor brokers taking on the role of market-makers on the new platform.
+
+On 1 February 2012 European Commission blocked the proposed merger of Deutsche Börse and NYSE Euronext. "The merger between Deutsche Börse and NYSE Euronext would have led to a near-monopoly in European financial derivatives worldwide. These markets are at the heart of the financial system and it is crucial for the whole European economy that they remain competitive. We tried to find a solution, but the remedies offered fell far short of resolving the concerns."[69] European competition commissioner, Joaquín Almunia, said.
+
+It is located in the city centre at the Börsenplatz. Deutsche Börse's headquarters are formally registered in Frankfurt but it moved most of its employees to a high-rise called "The Cube" in Eschborn in 2010, primarily due to significantly lower local corporate taxes.
+
+Frankfurt Trade Fair (Messe Frankfurt) has the third-largest exhibition site in the world with a total of 578,000 square metres (6,221,540 square feet). The trade fair premises are located in the western part between Bockenheim, the Westend and the Gallus district. It houses ten exhibition halls with a total of 321,754 square meters (3,463,331 square feet) of space and 96,078 square metres (1,034,175 square feet) of outdoor space.
+
+Hosted in Frankfurt are the Frankfurt Motor Show (Internationale Automobil-Ausstellung – IAA), the world's largest auto show, the Frankfurt Book Fair (Frankfurter Buchmesse), the world's largest book fair, the Ambiente Frankfurt, the world's largest consumer goods fair, the Achema, the world's largest plant engineering fair, and many more like Paperworld, Christmasworld, Beautyworld, Tendence Lifestyle or Light+Building.
+
+Messe Frankfurt GmbH, the owner and operator company, organized 87 exhibitions in 2010, 51 thereof in foreign countries. It is one of the largest trade fair companies with commercial activities in over 150 countries.
+
+A landmark building of the trade fair (and of the whole city) is the Messeturm (the name translates as Fair Trade Tower), which was the tallest building in Europe from 1991 to 1997. It is located on the north-east corner of the trade fair premises at the so-called city entrance. Despite the name it is not used for exhibition but serves as an office tower.
+
+Frankfurt Airport is one of the busiest airports in the world and is also the single largest place of work in Germany with over 500 companies which employ 71,500 people (2010).[70]
+
+The largest company at Frankfurt Airport is Lufthansa, Germany's flag carrier and Europe's largest airline. Lufthansa employs 35,000 people in Frankfurt.[71][72] The Lufthansa Aviation Center (LAC) is the main operation base of Lufthansa at Frankfurt Airport. The airport serves as Lufthansa's primary hub with 157 worldwide destinations (compared to 110 destinations at Munich Airport, Lufthansa's second-largest hub). Lufthansa Cargo is based in Frankfurt and operates its largest cargo center (LCC) at Frankfurt Airport. Lufthansa Flight Training is also based here.
+
+Fraport is the owner and operator of Frankfurt Airport. It is the airport's second-largest employer (19,800 workers in 2010).[73] Fraport also operates other airports worldwide, e.g., King Abdulaziz International Airport in Jeddah, Jorge Chávez International Airport in Lima and Antalya Airport.
+
+Condor is a German airline and part of Thomas Cook Group, based at Frankfurt Airport.
+
+Three of the four largest international accountancy and professional services firms (Big Four) are present.
+
+PricewaterhouseCoopers (PwC) German headquarters are located at Tower 185. KPMG moved its European Headquarters (KPMG Europe LLP) to The Squaire. Deloitte Touche Tohmatsu are present, while Ernst & Young is located in Eschborn.
+
+The three major international credit rating agencies – Standard & Poor's, Moody's and Fitch Ratings – have their German headquarters in Frankfurt.
+
+DWS Investments is the largest investment trust company in Germany and manages €288 billion fund assets. It is one of the 10 largest investment trust companies in the world.[74] Other large investment trust companies are Allianz Global Investors Europe (a division of Allianz SE, and a top-five global active investment manager with €1,933 billion assets under management globally), Union Investment and Deka Investmentfonds.
+
+Many of the largest international management consultancies are represented, including Arthur D. Little, McKinsey & Company, Boston Consulting Group, Booz & Company, Oliver Wyman, Bearing Point, Capgemini, Bain & Company and Roland Berger Strategy Consultants.
+
+Located in Frankfurt are the German headquarters of Jones Lang LaSalle and BNP Paribas Real Estate.
+
+Frankfurt has the highest concentration of lawyers in Germany, with one lawyer per 97 inhabitants (followed by Düsseldorf with a ratio of 1/117 and Munich with 1/124) in 2005.[75]
+
+Most of the large international law firms maintain offices, among them Allen & Overy, Baker & McKenzie, Bird & Bird, Clifford Chance, Cleary Gottlieb Steen & Hamilton, Debevoise & Plimpton, DLA Piper, Freshfields Bruckhaus Deringer, Hogan Lovells, Jones Day, Latham & Watkins, Linklaters, Mayer Brown, Milbank, Tweed, Hadley & McCloy, Norton Rose, Shearman & Sterling, Sidley Austin, SJ Berwin, Skadden, Arps, Slate, Meagher & Flom, Sullivan & Cromwell, K&L Gates, Taylor Wessing and White & Case.
+
+Although it is best known for its banks and financial institutions, Frankfurt is also a centre for media companies. Around 570 companies of the advertising industry and 270 public relations companies are there.
+
+According to a ranking of German FOCUS magazine (November 2007) seven of the 48 largest advertising agencies in Germany are based in Frankfurt, including Havas, Dentsu, McCann-Erickson, Saatchi & Saatchi, JWT, and Publicis.[76]
+
+Frankfurt is home to the German headquarters of Nestlé, the world's largest food company, located in Niederrad. Other important food companies are Ferrero SpA (German headquarters) and Radeberger Gruppe KG, the largest private brewery group in Germany.
+
+The South-Korean automobile manufacturer Kia Motors moved its European headquarters to Frankfurt in 2007. In the same year Italian manufacturer Fiat opened its new German headquarters. The automotive supplier Continental AG has the headquarters and a major manufacturing plant of its Chassis & Safety division (formerly ITT Automotive) located in Frankfurt Rödelheim.
+
+Some of the largest German construction companies have offices, e.g., Bilfinger Berger, Hochtief, Züblin and BAM Deutschland.
+
+Frankfurt has Germany's highest concentration of homeowners. This is partly attributed to the financial sector, but also to its cosmopolitan nature, with expatriates and immigrants representing one fourth of its population. For this reason Frankfurt's property market often operates differently than the rest of the country where the prices are generally flatter.
+
+Frankfurt is home to companies from the chemical, the transportation, the telecommunication and the energy industry. Some of the larger companies are:
+
+Within Frankfurt's urban area are several important companies.
+
+The business centre of Eschborn is located right at Frankfurt's city limits in the west and attracts businesses with significantly lower corporate taxes compared to Frankfurt. Major companies in Eschborn include Ernst & Young, Vodafone Germany, Randstad Holding and VR Leasing. Deutsche Börse moved most of its employees to Eschborn in 2010.
+
+Rüsselsheim is internationally known for its automobile manufacturer Opel, one of the biggest automobile manufacturers in Germany. With 20,000 employees in 2003, Opel was one of the five largest employers in Hesse.
+
+Offenbach am Main is home to the European headquarters of automobile manufacturer Hyundai Motor Company, to the German headquarters of automobile manufacturer Honda, to Honeywell Germany and to Deutscher Wetterdienst, the central scientific agency that monitors weather and meteorological conditions over Germany.
+
+Two DAX companies are located in Bad Homburg vor der Höhe, Fresenius SE & Co. KGaA and Fresenius Medical Care. Other major companies are Hewlett-Packard, Bridgestone, Deutsche Leasing and Basler Versicherungen.
+
+Kronberg im Taunus is home of the German headquarters of automobile manufacturer Jaguar Cars as well as the German headquarters of Accenture.
+
+Lufthansa Systems, a subsidiary of Lufthansa, is located in Kelsterbach.
+
+LSG Sky Chefs, another subsidiary of Lufthansa, is located in Neu-Isenburg.
+
+The German headquarters of Thomas Cook Group are based in Oberursel.
+
+Langen is home to Deutsche Flugsicherung, the German air traffic control.
+
+According to a ranking list (2001) produced by the University of Liverpool, Frankfurt is the richest city in Europe by GDP per capita, followed by Karlsruhe, Paris and Munich.[77]
+
+Frankfurt was voted the 7th in the Mercer Quality of Living Survey by the Mercer Quality of Living Survey (2012),[78] seventh in the Mercer Quality of Living Survey (2010) and 18th at the Economist's World's Most Liveable Cities Survey (2011).[79] According to an annual citizen survey (2010), arranged by the city council, 66 percent inhabitants are satisfied or highly satisfied with the city, while only 6 percent said that they are dissatisfied. Compared to the 1993's survey the number of satisfied inhabitants has grown about 22 percent while the number of dissatisfied inhabitants was reduced by 8 percent. 84 percent of the inhabitants like to live in Frankfurt, 13 percent would rather choose to live somewhere else. 37 percent are satisfied with the public safety (1993: only 9 percent), 22 percent are dissatisfied (1993: 64 percent).[80]
+
+Frankfurt consistently has the highest levels of crime per 100,000 inhabitants in Germany (15.976 crimes per annum in 2008) and is therefore dubbed the German "crime capital".[81] However, this statistic is often criticized[citation needed] because it ignores major factors: It is calculated based on the administrative 680,000-inhabitant figure while the urban area has 2.5 M inhabitants and on weekdays adds another million people[citation needed] (not counting the 53 million passengers passing through the airport each year). The rate for personal safety-relevant crimes such as murder, manslaughter, rape or bodily harm, is 3.4 percent, placing Frankfurt twelfth in the ranking (related to the official 680,000-inhabitant figure) or number 21 (related to the one-million-figure).[82] In 2018, the state of Hesse where Frankfurt lies ranked the third safest state in Germany.[83]
+
+The European Insurance and Occupational Pensions Authority (EIOPA) is an institution of the European Union and part of the European System of Financial Supervisors that was created in response to the financial crisis of 2007–2008. It was established on 1 January 2011.
+
+Frankfurt is one of two locations of the German Federal Financial Supervisory Authority (Bundesanstalt für Finanzdienstleistungsaufsicht, short: BaFin). The BaFin is an independent federal institution and acts as Germany's financial regulatory authority.
+
+Frankfurt is home to the German office of the International Finance Corporation (IFC), which is part of the World Bank Group. The IFC promotes sustainable private sector investment in developing countries.
+
+Frankfurt is one of two sites of the German National Library (Deutsche Nationalbibliothek), the other being Leipzig. The Deutsche Nationalbibliothek is the largest universal library in Germany. Its task, unique in Germany, is to collect, permanently archive, comprehensively document and record bibliographically all German and German-language publications from 1913 on, foreign publications about Germany, translations of German works and the works of German-speaking emigrants published abroad between 1933 and 1945, and to make them available to the public.
+
+Frankfurt is home to multiple trade unions and associations, including:
+
+trade associations include:
+
+Frankfurt is one of Germany's leading tourist destinations. In addition to its infrastructure and economy, its diversity supports a vibrant cultural scene. This blend of attractions led 4.3 million tourists (2012) to visit Frankfurt.[84] The Hotels in central Frankfurt offer 34,000 beds in 228 hotels, of which 13 are luxury hotels and 46 are first-class hotels.[85]
+
+Besides the tourist attractions in central Frankfurt many internationally famous sites are within 80 km (50 mi) of the city, such as:
+
+As a profoundly international city, Frankfurt hosts 92 diplomatic missions (consulates and consulates-general). Worldwide, only New York City and Hamburg are non-capital cities with more foreign representation. The Consulate General of the United States in Eckenheim is the largest American consulate in the world.
+
+Several courts are located in Frankfurt, including:
+
+Two important daily newspapers are published. The conservative Frankfurter Allgemeine Zeitung, also known as FAZ, was founded in 1949 and is the German newspaper with the widest circulation outside of Germany, with its editors claiming to deliver the newspaper to 148 countries every day. The FAZ has a circulation of over 380,000 copies daily. The other important newspaper, the Frankfurter Rundschau, was first published in 1945 and has a daily circulation of over 181,000.
+
+Several magazines also originate from Frankfurt. The local Journal Frankfurt is the best-known magazine for events, parties, and "insider tips". Öko-Test is a consumer-oriented magazine that focuses on ecological topics. Titanic is a well-known and often criticized satirical magazine with a circulation of approximately 100,000.
+
+Frankfurt's first radio station was the Südwestdeutsche Rundfunkdienst AG (Southwest German Broadcast Service), founded in 1924. Its successor service is the public broadcaster Hessischer Rundfunk (Hessian Broadcast Service). It is located at the "Funkhaus am Dornbusch" in the Dornbusch district and is one of the most important radio and television broadcasters in Hesse, with additional studios in Kassel, Darmstadt and Fulda.
+
+Bloomberg TV and RTL Television have regional studios.
+
+Other radio broadcasters include Main FM and Radio X.
+
+From August 1945 to October 2004, the American Forces Network (AFN) had broadcast from Frankfurt. Due to troop reductions the AFN's location has been closed with AFN now broadcasting from Mannheim.
+
+Frankfurt is home to the German office of Reuters, a global news agency.
+
+Frankfurt hosts two universities and several specialist schools. The two business schools are Goethe University Frankfurt's Goethe Business School and Frankfurt School of Finance & Management.
+
+The oldest and best-known university is the Johann Wolfgang Goethe University, with locations in Bockenheim, Westend, and Riedberg, and the university hospital in Niederrad. Goethe Business School is part of the University's House of Finance at Campus Westend. The Business School's Full Time MBA program has over 70% international students.
+
+The Frankfurt University of Applied Sciences was created out of several older organisations in 1971, and offers over 38 study areas, in the arts, sciences, engineering and law. Some of the most important research projects: Planet Earth Simulator, FraLine-IT-School-Service, quantitative analysis of methane in human corpses with the help of a mass spectrometer, software engineering (e.g., fraDesk), analysis of qualitative and quantitative gas in human lungs, long-term studies on photovoltaic modules (to name only a few).
+
+The city is also home to a business school, Frankfurt School of Finance & Management, formerly known as the Hochschule für Bankwirtschaft (Institution of Higher Learning for Banking Economics), with its new campus near Deutsche Nationalbibliothek U-Bahn stop (recently moving from its previous location in the Ostend (Eastend) neighbourhood). In 2001, it became a specialist institution for Economics and Management, or FOM. Frankfurt School is consistently ranked among the best business schools in the world, attributed to its high research output and quality of undergraduate and graduate training.[93]
+
+Frankfurt has the State Institution of Higher Learning for Artistic Education known as the Städelschule, founded in 1817 by Johann Friedrich Städel. It was taken over by the city in 1942 and turned into a state art school.
+
+Music institutions are the Frankfurt University of Music and Performing Arts, and the Hoch Conservatory (Dr. Hoch's Konservatorium) which was founded in 1878. The International Ensemble Modern Academy is a significant institution for the study of contemporary music.[94]
+
+The Sankt Georgen Graduate School of Philosophy and Theology (German:Philosophisch-Theologische Hochschule Sankt Georgen), a private institution with membership in the German Jesuit Association, has been located in Sachsenhausen since 1950.
+
+The city is home to three Max Planck Society institutes: the Max Planck Institute for European History of Law (MPIeR), Max Planck Institute for Biophysics, and the Max Planck Institute for Brain Research.
+
+The Frankfurt Institute for Advanced Studies, sponsored by several institutional and private sources, is involved in theoretical research in physics, chemistry, neuroscience, and computer science.
+
+Frankfurt is host to the Römisch-Germanische-Kommission (RGK), the German Archaeological Institute branch for prehistoric archaeology in Germany and Europe. The RGK is involved in a variety of research projects. Its library, with over 130,000 volumes, is one of the largest specialised archaeological libraries in the world.
+
+Frankfurt schools rank among the best equipped schools nationwide for availability of PCs and other media facilities. In order to assure maintenance and support of the school PCs, the city in cooperation with the University of Applied Sciences launched the project Fraline – IT-Schul-Service, an initiative employing students to provide basic school IT-support.
+
+Frankfurt is home to several professional sports teams. Some of them have won German Championships. E.g. the Skyliners Frankfurt won the German Basketball Championship in 2004 and the German Cup in 2000. Women's side 1. FFC Frankfurt are Germany's record title holders; Eintracht Frankfurt are one-time German champions, five-times winners of the DFB-Pokal, and winners of the UEFA Cup in 1980.
+Frankfurt hosts the following sports teams or clubs:
+
+Frankfurt is host to the classic cycle race Eschborn-Frankfurt City Loop (known as Rund um den Henninger-Turm from 1961 to 2008). The city hosts also the annual Frankfurt Marathon and the Ironman Germany. In addition to the former, it is one of 13 global host locations to the J.P. Morgan Corporate Challenge [6], Germany's biggest corporate sports event. Rhein-Main Eissport Club forms the base of the German bandy community.[7]

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+Frankfurt (officially: Frankfurt am Main (German: [ˈfʁaŋkfʊʁt ʔam ˈmaɪn] (listen); Hessian: Frangford am Maa, lit. "Frank ford on the[a] Main")) is a metropolis and the largest city of the German state of Hesse. Its 753,056 (2018) inhabitants make it the fifth-largest city in Germany. On the River Main (a tributary of the Rhine), it forms a continuous conurbation with the neighbouring city of Offenbach am Main and its urban area has a population of 2.3 million.[2][4] The city is at the centre of the larger Rhine-Main Metropolitan Region, which has a population of 5.5 million[1] and is Germany's second-largest metropolitan region after the Rhine-Ruhr Region. Frankfurt's central business district lies about 90 km (56 mi) northwest of the geographic centre of the EU at Gadheim, Lower Franconia. Like France and Franconia, the city is named after the Franks. Frankfurt is the largest city in the Rhine Franconian dialect area.
+
+Frankfurt was a city state, the Free City of Frankfurt, for nearly five centuries and was one of the most important cities of the Holy Roman Empire, as a site of imperial coronations; it lost its sovereignty upon the collapse of the empire in 1806, regained it in 1815 and then lost it again in 1866, when it was annexed (though neutral) by the Kingdom of Prussia. It has been part of the state of Hesse since 1945. Frankfurt is culturally, ethnically and religiously diverse, with half of its population, and a majority of its young people, having a migration background. A quarter of the population consists of foreign nationals, including many expatriates.
+
+Frankfurt is a global hub for commerce, culture, education, tourism and transportation, and rated as an "alpha world city" according to GaWC. It is the site of many global and European corporate headquarters. Frankfurt Airport is among the world's busiest. Frankfurt is one of the major financial centres of the European continent, with the headquarters of the European Central Bank, Deutsche Bundesbank, Frankfurt Stock Exchange, Deutsche Bank, DZ Bank, KfW, Commerzbank, several cloud and fintech startups[5] and other institutes. Automotive, technology and research, services, consulting, media and creative industries complement the economic base. Frankfurt's DE-CIX is the world's largest internet exchange point. Messe Frankfurt is one of the world's largest trade fairs. Major fairs include the Music Fair and the Frankfurt Book Fair, the world's largest book fair.
+
+Frankfurt is home to influential educational institutions, including the Goethe University, the UAS, the FUMPA and graduate schools like the Frankfurt School of Finance & Management. Its renowned cultural venues include the concert hall Alte Oper, Europe's largest English theatre and many museums (e.g. the Museumsufer ensemble with Städel and Liebieghaus, Senckenberg Natural Museum, Goethe House and the Schirn art venue at the old town). Frankfurt's skyline is shaped by some of Europe's tallest skyscrapers. The city is also characterised by various green areas and parks, including the central Wallanlagen, the City Forest, two major botanical gardens (the Palmengarten and the University's Botanical Garden) and the Frankfurt Zoo. In electronic music, Frankfurt has been a pioneering city since the 1980s, with renowned DJs including Sven Väth, Marc Trauner, Scot Project, Kai Tracid, and the clubs Dorian Gray, U60311, Omen and Cocoon. In sports, the city is known as the home of the top tier football club Eintracht Frankfurt, the Löwen Frankfurt ice hockey team, the basketball club Frankfurt Skyliners, the Frankfurt Marathon and the venue of Ironman Germany. It was also one of the host cities of the 1974 and 2006 FIFA World Cups.
+
+Frankfurt is the largest financial centre in continental Europe. It is home to the European Central Bank, Deutsche Bundesbank, Frankfurt Stock Exchange and several large commercial banks.
+
+The Frankfurt Stock Exchange is one of the world's largest stock exchanges by market capitalization and accounts for more than 90 percent of the turnover in the German market.
+
+In 2010, 63 national and 152 international banks had their registered offices in Frankfurt, including Germany's major banks, notably Deutsche Bank, DZ Bank, KfW and Commerzbank, as well as 41 representative offices of international banks.[6]
+
+Frankfurt is considered a global city (alpha world city) as listed by the GaWC group's 2012 inventory.[7] Among global cities it was ranked 10th by the Global Power City Index 2011 and 11th by the Global City Competitiveness Index 2012. Among financial centres it was ranked 8th by the International Financial Centers Development Index 2013 and 9th in the 2013 Global Financial Centres Index.
+
+Its central location within Germany and Europe makes Frankfurt a major air, rail and road transport hub. Frankfurt Airport is one of the world's busiest international airports by passenger traffic and the main hub for Germany's flag carrier Lufthansa. Frankfurt Central Station is one of the largest rail stations in Europe and the busiest junction operated by Deutsche Bahn, the German national railway company, with 342 trains a day to domestic and European destinations.[8] Frankfurter Kreuz, the Autobahn interchange close to the airport, is the most heavily used interchange in the EU, used by 320,000 cars daily.[9] In 2011 human-resource-consulting firm Mercer ranked Frankfurt as seventh in its annual 'Quality of Living' survey of cities around the world.[10] According to The Economist cost-of-living survey, Frankfurt is Germany's most expensive city and the world's 10th most expensive.[11]
+
+Frankfurt has many high-rise buildings in the city centre, forming the Frankfurt skyline. It is one of the few cities in the European Union to have such a skyline, which is why Germans sometimes refer to Frankfurt as Mainhattan, a portmanteau of the local Main River and Manhattan. The other well known and obvious nickname is Bankfurt. Before World War II the city was globally noted for its unique old town with timber-framed buildings, the largest timber-framed old town in Europe. The Römer area was later rebuilt and is popular with visitors and for events such as Christmas markets. Other parts of the old town were reconstructed as part of the Dom-Römer Project from 2012 to 2018.
+
+Frankonovurd (in Old High German) or Vadum Francorum (in Latin) were the first names mentioned in written records from 794. It transformed to Frankenfort during the Middle Ages and then to Franckfort and Franckfurth in the modern era. According to historian David Gans, the city was named c. 146 AD by its builder, a Frankish king named Zuna, who ruled over the province then known as Sicambri. He hoped thereby to perpetuate the name of his lineage.[12] The name is derived from the Franconofurd of the Germanic tribe of the Franks; Furt (cf. English ford) where the river was shallow enough to be crossed on foot.
+
+By the 19th century, the name Frankfurt had been established as the official spelling. The older English spelling of Frankfort is now rarely seen in reference to Frankfurt am Main, although more than a dozen other towns and cities, mainly in the United States, use this spelling (e.g., Frankfort, Kentucky; Frankfort, New York; Frankfort, Illinois).
+
+The suffix am Main has been used regularly since the 14th century. In English, the city's full name of Frankfurt am Main means "Frankfurt on the Main" (pronounced like English mine or German mein). Frankfurt is located on an ancient ford (German: Furt) on the Main River. As a part of early Franconia, the inhabitants were the early Franks, thus the city's name reveals its legacy as "the ford of the Franks on the Main".[13]
+
+Among English speakers, the city is commonly known simply as Frankfurt, but Germans occasionally call it by its full name to distinguish it from the other (significantly smaller) German city of Frankfurt an der Oder in the Land of Brandenburg on the Polish border.
+
+The city district Bonames has a name probably dating back to Roman times, thought to be derived from bona me(n)sa (good table).
+
+The common abbreviations for the city, primarily used in railway services and on road signs, are Frankfurt (Main), Frankfurt (M), Frankfurt a. M., Frankfurt/Main or Frankfurt/M. The common abbreviation for the name of the city is "FFM". Also in use is "FRA", the IATA code for Frankfurt Airport.
+
+Roman settlements were established in the area of the Römer, probably in the first century. Nida (Heddernheim) was also a Roman civitas capital.
+
+Alemanni and Franks lived there, and by 794, Charlemagne presided over an imperial assembly and church synod, at which Franconofurd (alternative spellings end with -furt and -vurd) was first mentioned.
+
+Frankfurt was one of the most important cities in the Holy Roman Empire. From 855, the German kings and emperors were elected and crowned in Aachen. From 1562, the kings and emperors were crowned in Frankfurt, initiated for Maximilian II. This tradition ended in 1792, when Franz II was elected. His coronation was deliberately held on Bastille Day, 14 July, the anniversary of the storming of the Bastille. The elections and coronations took place in St. Bartholomäus Cathedral, known as the Kaiserdom (Emperor's Cathedral), or its predecessors.
+
+The Frankfurter Messe (Frankfurt Trade Fair) was first mentioned in 1150. In 1240, Emperor Friedrich II granted an imperial privilege to its visitors, meaning they would be protected by the empire. The fair became particularly important when similar fairs in French Beaucaire lost attraction around 1380. Book trade fairs began in 1478.
+
+In 1372, Frankfurt became a Reichsstadt (Imperial Free City), i.e., directly subordinate to the Holy Roman Emperor and not to a regional ruler or a local nobleman.
+
+In 1585, Frankfurt traders established a system of exchange rates for the various currencies that were circulating to prevent cheating and extortion. Therein lay the early roots for the Frankfurt Stock Exchange.
+
+Frankfurt managed to remain neutral during the Thirty Years' War, but suffered from the bubonic plague that refugees brought to the city. After the war, Frankfurt regained its wealth. In the late 1770s the theatre principal Abel Seyler was based in Frankfurt, and established the city's theatrical life.[14]
+
+Following the French Revolution, Frankfurt was occupied or bombarded several times by French troops. It remained a free city until the collapse of the Holy Roman Empire in 1805/6. In 1806, it became part of the principality of Aschaffenburg under the Fürstprimas (Prince-Primate), Karl Theodor Anton Maria von Dalberg. This meant that Frankfurt was incorporated into the confederation of the Rhine. In 1810, Dalberg adopted the title of a Grand Duke of Frankfurt. Napoleon intended to make his adopted son Eugène de Beauharnais, already Prince de Venise ("prince of Venice", a newly established primogeniture in Italy), Grand Duke of Frankfurt after Dalberg's death (since the latter as a Catholic bishop had no legitimate heirs). The Grand Duchy remained a short episode lasting from 1810 to 1813, when the military tide turned in favour of the Anglo-Prussian lead allies that overturned the Napoleonic order. Dalberg abdicated in favour of Eugène de Beauharnais, which of course was only a symbolic action, as the latter effectively never ruled after the ruin of the French armies and Frankfurt's takeover by the allies.
+
+After Napoleon's final defeat and abdication, the Congress of Vienna (1814–1815) dissolved the grand-duchy and Frankfurt became a fully sovereign city state with a republican form of government. Frankfurt entered the newly founded German Confederation (till 1866) as a free city, becoming the seat of its Bundestag, the confederal parliament where the nominally presiding Habsburg Emperor of Austria was represented by an Austrian "presidential envoy".
+
+After the ill-fated revolution of 1848, Frankfurt was the seat of the first democratically elected German parliament, the Frankfurt Parliament, which met in the Frankfurter Paulskirche (St. Paul's Church) and was opened on 18 May 1848. The institution failed in 1849 when the Prussian king, Frederick William IV, declared that he would not accept "a crown from the gutter". In the year of its existence, the assembly developed a common constitution for a unified Germany, with the Prussian king as its monarch.
+
+Frankfurt lost its independence after the Austro-Prussian War in 1866 when Prussia annexed several smaller states, among them the Free City of Frankfurt. The Prussian administration incorporated Frankfurt into its province of Hesse-Nassau. The Prussian occupation and annexation was perceived as a great injustice in Frankfurt, which retained its distinct western European, urban and cosmopolitan character. The formerly independent towns of Bornheim and Bockenheim were incorporated in 1890.
+
+In 1914, the citizens founded the University of Frankfurt, later named Goethe University Frankfurt. This marked the only civic foundation of a university in Germany; today it is one of Germany's largest.
+
+From 6 April to 17 May 1920, following military intervention to put down the Ruhr uprising, Frankfurt was occupied by French troops.[15] The French claimed that Articles 42 to 44 of the peace treaty of Versailles concerning the demilitarisation of the Rhineland had been broken.[16] In 1924, Ludwig Landmann became the first Jewish mayor of the city, and led a significant expansion during the following years. During the Nazi era, the synagogues of the city were destroyed.
+
+Frankfurt was severely bombed in World War II (1939–1945). About 5,500 residents were killed during the raids, and the once-famous medieval city centre, by that time the largest in Germany, was almost completely destroyed. It became a ground battlefield on 26 March 1945, when the Allied advance into Germany was forced to take the city in contested urban combat that included a river assault. The 5th Infantry Division and the 6th Armored Division of the United States Army captured Frankfurt after several days of intense fighting, and it was declared largely secure on 29 March 1945.[17]
+
+After the end of the war, Frankfurt became a part of the newly founded state of Hesse, consisting of the old Hesse-(Darmstadt) and the Prussian Hesse provinces. The city was part of the American Zone of Occupation of Germany. The Military Governor for the United States Zone (1945–1949) and the United States High Commissioner for Germany (HICOG) (1949–1952) had their headquarters in the IG Farben Building, intentionally left undamaged by the Allies' wartime bombardment.
+
+Frankfurt was the original choice for the provisional capital city of the newly founded state of West Germany in 1949. The city constructed a parliament building that was never used for its intended purpose (it housed the radio studios of Hessischer Rundfunk). In the end, Konrad Adenauer, the first postwar Chancellor, preferred the town of Bonn, for the most part because it was close to his hometown, but also because many other prominent politicians opposed the choice of Frankfurt out of concern that Frankfurt would be accepted as the permanent capital, thereby weakening the West German population's support for a reunification with East Germany and the eventual return of the capital to Berlin.
+
+Postwar reconstruction took place in a sometimes simple modern style, thus changing Frankfurt's architectural face. A few landmark buildings were reconstructed historically, albeit in a simplified manner (e.g., Römer, St. Paul's Church, and Goethe House). The collection of historically significant Cairo Genizah documents of the Municipal Library was destroyed by the bombing. According to Arabist and Genizah scholar S.D. Goitein, "not even handlists indicating its contents have survived."[18]
+
+The end of the war marked Frankfurt's comeback as Germany's leading financial centre, mainly because Berlin, now a city divided into four sectors, could no longer rival it. In 1948, the allies founded the Bank deutscher Länder, the forerunner of Deutsche Bundesbank. Following this decision, more financial institutions were re-established, e.g. Deutsche Bank and Dresdner Bank. In the 1950s, Frankfurt Stock Exchange regained its position as the country's leading stock exchange.
+
+Frankfurt also re-emerged as Germany's transportation centre and Frankfurt Airport became Europe's second-busiest airport behind London Heathrow Airport in 1961.
+
+During the 1970s, the city created one of Europe's most efficient underground transportation systems.[19] That system includes a suburban rail system (S-Bahn) linking outlying communities with the city centre, and a deep underground light rail system with smaller coaches (U-Bahn) also capable of travelling above ground on rails.
+
+In 1998, the European Central Bank was founded in Frankfurt, followed by the European Insurance and Occupational Pensions Authority and European Systemic Risk Board in 2011.
+
+Frankfurt is the largest city in the federated state of Hesse in the south-western part of Germany.
+
+Frankfurt is located on both sides of the Main River, south-east of the Taunus mountain range. The southern part of the city contains the Frankfurt City Forest, Germany's largest city forest. The city area is 248.31 km2 (95.87 sq mi) and extends over 23.4 km (14.54 mi) east to west and 23.3 km (14.48 mi) north to south. The city centre is north of the River Main in Altstadt district (the historical centre) and the surrounding Innenstadt district. The geographical centre is in Bockenheim district near Frankfurt West station.
+
+Frankfurt is the centre of the densely populated Frankfurt Rhine-Main Metropolitan Region with a population of 5.5 million. Other important cities in the region are Wiesbaden (capital of Hesse), Mainz (capital of Rhineland-Palatinate), Darmstadt, Offenbach am Main, Hanau, Aschaffenburg, Bad Homburg vor der Höhe, Rüsselsheim, Wetzlar and Marburg.
+
+The city is divided into 46 city districts (Stadtteile), which are in turn divided into 121 city boroughs (Stadtbezirke) and 448 electoral districts (Wahlbezirke). The 46 city districts combine into 16 area districts (Ortsbezirke), which each have a district committee and chairperson.
+
+The largest city district by population and area is Sachsenhausen, while the smallest is Altstadt, Frankfurt's historical center. Three larger city districts (Sachsenhausen, Westend and Nordend) are divided for administrative purposes into a northern (-Nord) and a southern (-Süd) part, respectively a western (-West) and an eastern (-Ost) part, but are generally considered as one city district (which is why often only 43 city districts are mentioned, even on the City's official website).[20]
+
+Some larger housing areas are often falsely called city districts, even by locals, like Nordweststadt (part of Niederursel, Heddernheim and Praunheim), Goldstein (part of Schwanheim), Riedberg (part of Kalbach-Riedberg) and Europaviertel (part of Gallus). The Bankenviertel (banking district), Frankfurt's financial district, is also not an administrative city district (it covers parts of the western Innenstadt district, the southern Westend district and the eastern Bahnhofsviertel district).
+
+Many city districts are incorporated suburbs (Vororte), or were previously independent cities, such as Höchst. Some like Nordend and Westend arose during the rapid growth of the city in the Gründerzeit following the Unification of Germany, while others were formed from territory which previously belonged to other city district(s), such as Dornbusch and Riederwald.
+
+Until the year 1877 the city's territory consisted of the present-day inner-city districts of Altstadt, Innenstadt, Bahnhofsviertel, Gutleutviertel, Gallus, Westend, Nordend, Ostend and Sachsenhausen.
+
+Bornheim was part of an administrative district called Landkreis Frankfurt, before becoming part of the city on 1 January 1877, followed by Bockenheim on 1 April 1895. Seckbach, Niederrad and Oberrad followed on 1 July 1900. The Landkreis Frankfurt was finally dispersed on 1 April 1910, and therefore Berkersheim, Bonames, Eckenheim, Eschersheim, Ginnheim, Hausen, Heddernheim, Niederursel, Praunheim, Preungesheim and Rödelheim joined the City. In the same year a new city district, Riederwald, was created on territory that had formerly belonged to Seckbach and Ostend.
+
+On 1 April 1928 the City of Höchst became part of Frankfurt, as well as its city districts Sindlingen, Unterliederbach and Zeilsheim. Simultaneously the Landkreis Höchst was dispersed with its member cities either joining Frankfurt (Fechenheim, Griesheim, Nied, Schwanheim, Sossenheim) or joining the newly established Landkreis of Main-Taunus-Kreis.
+
+Dornbusch became a city district in 1946. It was created on territory that had formerly belonged to Eckenheim and Ginnheim.
+
+On 1 August 1972 Hesse's smaller suburbs of Harheim, Kalbach, Nieder-Erlenbach, and Nieder-Eschbach became districts while other neighbouring suburbs chose to join the Main-Taunus-Kreis, the Landkreis Offenbach, the Kreis Groß-Gerau, the Hochtaunuskreis, the Main-Kinzig-Kreis or the Wetteraukreis.
+
+Bergen-Enkheim was the last suburb to become part of Frankfurt on 1 January 1977.
+
+Flughafen became an official city district in 1979. It covers the area of Frankfurt Airport that had belonged to Sachsenhausen and the neighbouring city of Mörfelden-Walldorf.
+
+Frankfurt's youngest city district is Frankfurter Berg. It was part of Bonames until 1996.
+
+Kalbach was officially renamed Kalbach-Riedberg in 2006 because of the large residential housing development in the area known as Riedberg.
+
+To the west Frankfurt borders the administrative district (Landkreis) of Main-Taunus-Kreis with towns such as Hattersheim am Main, Kriftel, Hofheim am Taunus, Kelkheim, Liederbach am Taunus, Sulzbach, Schwalbach am Taunus and Eschborn; to the northwest the Hochtaunuskreis with Steinbach, Oberursel (Taunus) and Bad Homburg vor der Höhe; to the north the Wetteraukreis with Karben and Bad Vilbel; to the northeast the Main-Kinzig-Kreis with Niederdorfelden and Maintal; to the southeast the city of Offenbach am Main; to the south the Kreis Offenbach with Neu-Isenburg and to the southwest the Kreis Groß-Gerau with Mörfelden-Walldorf, Rüsselsheim and Kelsterbach.
+
+Together with these towns (and some larger nearby towns, e.g., Hanau, Rodgau, Dreieich, Langen) Frankfurt forms a contiguous built-up urban area called Stadtregion Frankfurt which is not an official administrative district. The urban area had an estimated population of 2.3 million in 2010 and is therefore the 13th largest urban area in the European Union.
+
+Frankfurt has a temperate-oceanic climate (Köppen: Cfb). Its average annual temperature is 10.6 °C (51.1 °F), with monthly mean temperatures ranging from 1.6 °C (34.9 °F) in January to 20.0 °C (68.0 °F) in July.
+
+With a population of 732,688 (2015) within its administrative boundaries[24] and of 2,300,000 in the actual urban area,[4] Frankfurt is the fifth largest city in Germany after Berlin, Hamburg, Munich and Cologne. 
+Central Frankfurt has been a Großstadt (a city with at least 100,000 residents by definition) since 1875. With 414,576 residents in 1910, it was the ninth largest city in Germany and the number of inhabitants grew to 553,464 before World War II. After the war, at the end of the year 1945, the number had dropped to 358,000. In the following years, the population grew again and reached an all-time-high of 691,257 in 1963. It dropped again to 592,411 in 1986 but has increased since then. According to the demographic forecasts for central Frankfurt, the city will have a population up to 825,000 within its administrative boundaries in 2020 and more than 2.5 million inhabitants in its urban area.
+
+During the 1970s, the state government of Hesse wanted to include the entire urban area into its administrative boundaries. This would have made Frankfurt officially the second largest city in Germany after Berlin with up to 3 million inhabitants.[25] However, because local authorities did not agree the administrative territory is still much smaller than its actual urban area.
+
+According to data from the city register of residents, 51.2% of the population had a migration background as of 2015, which means that a person or at least one or both of their parents was born with foreign citizenship. For the first time, a majority of the city residents had an at least part non-German background.[28] Moreover, three of four children in the city under the age of six had immigrant backgrounds.[29] and 27.7% of residents had a foreign citizenship.[30]
+
+According to statistics, 46.7% of immigrants in Frankfurt come from other countries in The European Union, 24.5% of immigrants in Frankfurt come from European countries that are not part of the EU, 15.7% of immigrants in Frankfurt come from Asia (including Western Asia and South Asia), 7.3% of immigrants in Frankfurt come from Africa, 3.4% of immigrants in Frankfurt come from North America (Including the Caribbean and Central America), 0.2% of immigrants in Frankfurt come from Australia and Zealandia, 2.3% of immigrants in Frankfurt come from South America and 1.1% of immigrants in Frankfurt come from The Pacific Island Nations. Because of this, the city is often considered to be a multicultural city and has been compared to New York City and London.
+
+Frankfurt was historically a Protestant-dominated city. However, during the 19th century an increasing number of Catholics moved there. The Jewish community has a history dating back to Medieval times and has always ranked among the largest in Germany. Two synagogues operate there. Due to the growing immigration of people from Muslim countries beginning in the 1960s, Frankfurt has a large Muslim community. The Ahmadiyya Noor Mosque, constructed in 1959, is the city's largest mosque and the third largest in Germany.[31]
+
+As of 2013[update], the largest Christian denominations were Catholicism (22.7% of the population) and Protestantism, especially Lutheranism (19.4%).[32] Estimations put the share of Muslim inhabitants at approximately 12% (2006).[33] According to calculations based on census data for 21 countries of origin, the number of Muslim migrants in Frankfurt amounted to about 84,000 in 2011, making up 12.6 percent of the population.[34] A large part of them was from Turkey and Morocco. Over 7,000 inhabitants were affiliated with the Jewish community, amounting to approximately 1% of the population.[35]
+
+Frankfurt is one of five independent district-free cities (kreisfreie Städte) in Hesse, which means that it does not form part of another general-purpose local government entity, in this case it is not part of a Landkreis. The other four cities are the second to fifth largest cities in Hesse: Wiesbaden, Kassel, Darmstadt and Offenbach am Main. A kreisfreie Stadt has territorial sovereignty within its defined city limits.
+
+In 1995 Petra Roth of the Christian Democratic Union (CDU) became Lord Mayor (Oberbürgermeisterin), Frankfurt's municipal leader. In 2012, Peter Feldmann (SPD) succeeded Roth as Lord Mayor. The CDU and the Alliance '90/The Greens (Bündnis '90/Die Grünen) formed the government.
+
+Frankfurt is twinned with:
+
+
+
+
+
+Partnerships and city friendships are a weaker form of cooperation than the sister city relationship, acting more like a fixed-term cooperation or limited to certain projects. Frankfurt has partnerships with the following cities:
+
+Römer
+
+Römer, the German word for Roman, is a complex of nine houses that form the Frankfurt city hall (Rathaus). The houses were acquired by the city council in 1405 from a wealthy merchant family. The middle house became the city hall and was later connected with its neighbours. The Kaisersaal ("Emperor's Hall") is located on the upper floor and is where the newly crowned emperors held their banquets. The Römer was partially destroyed in World War II and later rebuilt. The surrounding square, the Römerberg, is named after the city hall.
+
+The former Altstadt (old town) quarter between the Römer and the Frankfurt Cathedral was redeveloped as the Dom-Römer Quarter from 2012 to 2018, including 15 reconstructions of historical buildings that were destroyed during World War II.
+
+Frankfurt Cathedral
+
+Frankfurt Cathedral (Frankfurter Dom) is not a cathedral, but the main Catholic church, dedicated to St. Bartholomew. The Gothic building was constructed in the 14th and 15th centuries on the foundation of an earlier church from the Merovingian time. From 1356 onwards, kings of the Holy Roman Empire were elected in this church, and from 1562 to 1792, Roman-German emperors were crowned there.
+
+Since the 18th century, St. Bartholomew's has been called Dom, although it was never a bishop's seat. In 1867 it was destroyed by fire and rebuilt in its present style. It was again partially destroyed in World War II and rebuilt in the 1950s. Its height is 95 meters. The cathedral tower has a viewing platform open to the public at a height of 66 meters, accessed through a narrow spiral staircase with 386 steps.
+
+St. Paul's Church
+
+St. Paul's Church (Paulskirche) is a national historic monument in Germany because it was the seat of the first democratically elected parliament in 1848. It was established in 1789 as a Protestant church, but was not completed until 1833. Its importance has its roots in the Frankfurt Parliament, which met in the church during the revolutionary years of 1848/49 in order to write a constitution for a united Germany. The attempt failed because the monarchs of Prussia and Austria did not want to lose power. In 1849 Prussian troops ended the democratic experiment by force and the parliament dissolved. Afterwards, the building was used for church services again.
+
+St. Paul's was partially destroyed in World War II, particularly its interior, which now has a modern appearance. It was quickly and symbolically rebuilt after the war; today it is used mainly for exhibitions and events.
+
+Archäologischer Garten Frankfurt
+
+The Archaeological Garden contains small parts of the oldest recovered buildings: an ancient Roman settlement and the Frankfurt Royal Palace (Kaiserpfalz Frankfurt) from the 6th century. The garden is located between the Römerberg and the Cathedral. It was discovered after World War II when the area was heavily bombed and later partly rebuilt. The remains were preserved and are now open to the public. There are plans underway to construct a building on top of the garden but anyhow it is decided that the garden will stay open to the public.
+
+Haus Wertheim
+
+Wertheim House is the only timbered house in the Altstadt district that survived the heavy bombings of World War II undamaged. It is located on the Römerberg next to the Historical Museum.
+
+Saalhof
+
+The Saalhof is the oldest conserved building in the Altstadt district and dates to the 12th century. It was used as an exhibition hall by Dutch clothiers when trade fairs were held during the 14th and 15th century. The Saalhof was partly destroyed in World War II and later rebuilt. Today it serves as a part of the Historical Museum.
+
+Eiserner Steg
+
+The Eiserner Steg (Iron Bridge) is a pedestrian-only bridge across the Main that connects Römerberg and Sachsenhausen. It was built in 1868 and was the second bridge to cross the river. After World War II, when it was blown up by the Wehrmacht, it was quickly rebuilt in 1946. Today some 10,000 people cross the bridge on a daily basis.
+
+Alte Oper
+
+The Alte Oper is a former opera house, hence the name "Old Opera". The opera house was built in 1880 by architect Richard Lucae. It was one of the major opera houses in Germany until it was heavily damaged in World War II. Until the late 1970s, it was a ruin, nicknamed "Germany's most beautiful ruin". Former Frankfurt Lord Mayor Rudi Arndt called for blowing it up in the 1960s, which earned him the nickname "Dynamite-Rudi". (Later on, Arndt said he never had meant his suggestion seriously.)
+
+Public pressure led to its refurbishment and reopening in 1981. Today, it functions as a famous concert hall, while operas are performed at the "new" Frankfurt Opera. The inscription on the frieze of the Alte Oper says: "Dem Wahren, Schönen, Guten" ("To the true, the beautiful, the good").
+
+Eschenheimer Turm
+
+The Eschenheim Tower (Eschenheimer Turm) was erected at the beginning of the 15th century and served as a city gate as part of late-medieval fortifications. It is the oldest and most unaltered building in the Innenstadt district.
+
+St. Catherine's Church
+
+St. Catherine's Church (Katharinenkirche) is the largest Protestant church, dedicated to Catherine of Alexandria, a martyred early Christian saint. It is located in the city centre at the entrance to the Zeil, the central pedestrian shopping street.
+
+Hauptwache
+
+Although today Hauptwache is mostly associated with the inner-city underground train station of the same name, the name originates from a baroque building on the square above the station. The Hauptwache building was constructed in 1730 and was used as a prison, therefore the name that translates as "main guard-house". Today the square surrounding the building is also called "Hauptwache" (formal: An der Hauptwache). It is situated in the city centre opposite to St. Catherine's Church and houses a famous café.
+
+Central Station
+
+Frankfurt Central Station (Frankfurt Hauptbahnhof), which opened in 1888, was built as the central train station for Frankfurt to replace three smaller train stations in the city centre and to boost the needed capacity for travellers. It was constructed as a terminus station and was the largest train station in Europe by floor area until 1915 when Leipzig Central Station was opened. Its three main halls were constructed in a neorenaissance-style, while the later enlargement with two outer halls in 1924 was constructed in neoclassic-style.
+
+Frankfurter Hof
+
+The Frankfurter Hof is a landmarked hotel in the city centre at Kaiserplatz, built from 1872 to 1876. It is part of Steigenberger Hotels group and is considered the city's most prestigious.
+
+St. Leonhard
+
+St. Leonhard, on the Main close to the bridge Eiserner Steg, is a Catholic late Gothic hall church, derived from a Romanesque style basilica beginning in 1425. It is the only one of nine churches in the Old Town that survived World War II almost undamaged. The parish serves the English-speaking community. The church has been under restoration since 2011.
+
+Frankfurt is one of the few European cities with a significant number of skyscrapers, (buildings at least 150 m (492.13 ft) tall). It hosts 17 out of Germany's 18 skyscrapers. Most skyscrapers and high-rise office buildings are located in the financial district (Bankenviertel) near the city centre, around the trade fair premises (Europaviertel) and at Mainzer Landstraße between Opernplatz and Platz der Republik, which connects the two areas.
+
+The 17 skyscrapers are:
+
+Other high-rise buildings include:
+
+For centuries, St. Bartholomeus's Cathedral was the tallest structure. The first building to exceed the 95-metre-high cathedral was not an office building but a grain silo, the 120-metre-high (390 ft) Henninger Turm, built from 1959 to 1961.
+
+The first high-rise building boom came in the 1970s when Westend Gate (then called Plaza Büro Center) and Silberturm were constructed and became the tallest buildings in Germany with a height of 159.3 metres and 166.3 metres, respectively. Around the same time, Frankfurter Büro Center and City-Haus (142.4 metres and 142.1 metres) were constructed at Mainzer Landstraße and Eurotower (148.0 metres) and Garden Tower (127.0 metres; then called Helaba-Hochhaus) were constructed in the financial district.
+
+None of the buildings constructed during the 1980s surpassed Silberturm. The most famous buildings from this decade are the Deutsche Bank Twin Towers at Taunusanlage, both 155.0 metres tall.
+
+The 1990s featured a second wave. Messeturm, built on the trade fair site, reached a height of 256.5 metres and became the tallest building in Europe by 1991. It was overtaken by the 259-metre-high (850 ft) Commerzbank Tower in 1997. Other tall buildings from this decade are Westendstrasse 1 (208.0 metres), Main Tower (200.0 metres) and Trianon (186.0 metres).
+
+In 21st-century Frankfurt, more high-rise buildings and skyscrapers (e.g., Skyper, Opernturm, Tower 185, Seat of the European Central Bank, Taunusturm) emerged, but none have surpassed Commerzbank Tower.
+
+With a large forest, many parks, the Main riverbanks and the two botanical gardens, Frankfurt is considered a "green city": More than 50 percent of the area within the city limits are protected green areas.[42]
+
+With more than 30 museums, Frankfurt has one of the largest variety of museums in Europe. 20 museums are part of the Museumsufer, located on the front row of both sides of the Main riverbank or nearby, which was created on an initiative by cultural politician Hilmar Hoffmann.
+
+Ten museums are located on the southern riverbank in Sachsenhausen between the Eiserner Steg and the Friedensbrücke. The street itself, Schaumainkai, is partially closed to traffic on Saturdays for Frankfurt's largest flea market.
+
+Two museums are located on the northern riverbank:
+
+Not directly located on the northern riverbank in the Altstadt district are:
+
+Another important museum is located in the Westend district:
+
+Other museums are the Dialogmuseum (Dialogue Museum) in the Ostend district, Eintracht Frankfurt Museum at Commerzbank-Arena, Explora Museum+Wissenschaft+Technik (Explora Museum of Science and Engineering) in the Nordend district, the Frankfurter Feldbahnmuseum (Light Railway Museum Frankfurt) in the Gallus district, the Verkehrsmuseum Frankfurt (Transport Museum Frankfurt) in the Schwanheim district, the Hammer Museum in the Bahnhofsviertel district and the Geldmuseum der Deutschen Bundesbank (Money Museum of the German Federal Bank) in the Ginnheim district.
+
+Eurodance and Trance music originated in Frankfurt. In 1989 German producers Michael Münzing and Luca Anzilotti (under the pseudonyms Benito Benites and John "Virgo" Garrett III) formed the Snap! project. Snap! songs combined Rap and Soul vocals adding rhythm by using computer technology and mixing electronic sounds, bass and drums. By doing so a new genre was born: Eurodance.[43] In the early 1990s, DJs including Sven Väth and DJ DAG (of Dance 2 Trance) first played a harder, deeper style of acid house that became popular worldwide over the next decade as Trance music. Some of the early and most influential Eurodance, Trance and Techno acts, e.g., La Bouche, Jam and Spoon, Magic Affair, Culture Beat, Snap!, Dance 2 Trance, Oliver Lieb and Hardfloor, and record labels such as Harthouse and Eye Q, were based in the city in the early 1990s.
+
+Frankfurt is home to two major botanical gardens.
+
+Frankfurt offers a variety of restaurants, bars, pubs and clubs. Clubs concentrate in and around the city centre and in the Ostend district, mainly close to Hanauer Landstraße. Restaurants, bars and pubs concentrate in Sachsenhausen, Nordend, Bornheim and Bockenheim.
+
+One of the main venues of the early Trance music sound was the Omen nightclub (closed 1998). Another popular disco club of the 1980-1990s and a hotspot for Techno/Trance music was the Dorian Gray, located within Terminal 1 at Frankfurt Airport. Because of the location at the airport the club had no restrictions regarding opening hours. The club had to close at the end of 2000 because of stricter fire safety regulations. Also notable for its extraordinary design was Coocoon Club in Fechenheim which opened in 2004 was and voted best techno club of the year by music magazines "Groove" and "Raveline" in 2004, 2005, 2006 and 2007. It closed in 2012.[45]
+
+The city can be accessed from around the world via Frankfurt Airport (Flughafen Frankfurt am Main) located 12 km (7 mi) southwest of the city centre. The airport has four runways and serves 265 non-stop destinations. Run by transport company Fraport it ranks among the world's busiest airports by passenger traffic and is the busiest airport by cargo traffic in Europe. The airport also serves as a hub for Condor and as the main hub for German flag carrier Lufthansa. It is the busiest airport in Europe in terms of cargo traffic, and the fourth busiest in Europe in terms of passenger traffic behind London Heathrow Airport, Paris Charles de Gaulle Airport and Amsterdam Airport Schiphol. Passenger traffic at Frankfurt Airport in 2018 was 69,510,269 passengers.
+
+A third terminal is being constructed (planned to open in 2023). The third terminal will increase the capacity of the airport to over 90 million passengers per year.[49]
+
+The airport can be reached by car or bus and has two railway stations, one for regional and one for long-distance traffic. The S-Bahn lines S8 and S9 (direction Offenbach Ost or Hanau Hbf) departing at the regional station take 10–15 minutes from the airport to Frankfurt Central Station and onwards to the city centre (Hauptwache station), the IC and ICE trains departing at the long-distance station take 10 minutes to Frankfurt Central Station.
+
+Despite the name, Frankfurt Hahn Airport (Flughafen Frankfurt-Hahn) is situated approximately 120 km (75 mi) from the city in Lautzenhausen (Rhineland-Palatinate). Hahn Airport is a major base for low-cost carrier Ryanair. This airport can only be reached by car or bus. An hourly bus service runs from Frankfurt Central Station, taking just over 2 hours [50]. Passenger traffic at Hahn Airport in 2010 was 3.5 million.
+
+Frankfurt Egelsbach Airport (Flugplatz Frankfurt-Egelsbach) is a busy general aviation airport located south-east of Frankfurt Airport, near Egelsbach.
+
+Frankfurt is a traffic hub for the German motorway (Autobahn) system. The Frankfurter Kreuz is an Autobahn interchange close to the airport, where the Bundesautobahn 3 (A3), Cologne to Würzburg, and the Bundesautobahn 5 (A5), Basel to Hanover, meet. With approximately 320,000 cars passing through it every day it is Europe's most heavily used interchange. The Bundesautobahn 66 (A66) connects Frankfurt with Wiesbaden in the west and Fulda in the east. The Bundesautobahn 661 (A661) is mainly a commuter motorway which starts in the south (Egelsbach), runs through the eastern part and ends in the north (Oberursel). The Bundesautobahn 648 (A648) is a very short motorway in the western part which primarily serves as a fast connection between the A 66 and the Frankfurt Trade Fair. The A5 in the west, the A3 in the south and the A661 in the north-east form a ring road around the inner city districts and define a Low-emission zone (Umweltzone; established in 2008), meaning that vehicles have to meet certain emission criteria to enter the zone.
+
+The streets of central Frankfurt are usually congested with cars during rush hour. Some areas, especially around the shopping streets Zeil, Goethestraße and Freßgass, are pedestrian-only streets. Car parks are located throughout the city and especially in the city centre.
+
+Frankfurt Central Station (Frankfurt Hauptbahnhof, often abbreviated as Frankfurt (Main) Hbf or F-Hbf) is the largest railway station in Germany by railway traffic. By daily passenger volume, it ranks second together with Munich Central Station (350,000 each) after Hamburg Central Station (450,000). It is located between the Gallus, the Gutleutviertel and the Bahnhofsviertel district, not far away from the trade fair and the financial district. It serves as a major hub for long-distance trains (InterCity, ICE) and regional trains as well as for Frankfurt's public transport system. It is a stop for most of ICE high speed lines, making it Germany's most important ICE station. ICE Trains to London via the Channel Tunnel were planned for 2013.[51] All Rhine-Main S-Bahn lines, two U-Bahn lines (U4, U5), several tram and bus lines stop there. Regional and local trains are integrated in the Public transport system Rhein-Main-Verkehrsverbund (RMV), the second largest integrated public transport systems in the world, after Verkehrsverbund Berlin-Brandenburg.
+
+Frankfurt Airport can be accessed by two railway stations: Frankfurt Airport long-distance station (Frankfurt Flughafen Fernbahnhof) is only for long-distance traffic and connects the airport to the main rail network, with most of the ICE services using the Cologne-Frankfurt high-speed rail line. The long-distance station is located outside the actual airport ground but has a connecting bridge for pedestrians to Terminal 1, concourse B. Frankfurt Airport regional station (Frankfurt Flughafen Regionalbahnhof) is for local S-Bahn trains (lines S8, S9) and regional trains. The regional station is located within Terminal 1, concourse B.
+
+Frankfurt's third long-distance station is Frankfurt South station (Frankfurt Südbahnhof, often abbreviated as Frankfurt (Main) Süd or F-Süd), located in Sachsenhausen. It is an important destination for local trains and trams (lines 14 to 16, 19) and the terminal stop for four U-Bahn lines (U1, U2, U3, U8) and four S-Bahn lines (S3, S4, S5, S6).
+
+The Frankfurt Trade Fair offers two railway stations: Messe station is for local S-Bahn trains (lines S3-S6) and is located at the centre of the trade fair premises while Festhalle/Messe station is served by U-Bahn line U4 and is located at the north-east corner of the premises.
+
+Two other major railway stations in the city centre are Konstablerwache and Hauptwache, located on each end of the Zeil. They are the main stations to change from east-to-west-bound S-Bahn trains to north-to-south-bound U-Bahn trains. Konstablerwache station is the second-busiest railway station regarding daily passenger volume (191,000) after the central station. The third-busiest railway station is Hauptwache station (181,000).[citation needed][52]
+
+There are three stations for intercity bus services in Frankfurt: one at the south side of the Central Station, one at the Terminal 2 of the airport and another one at Stephanstraße.[53]
+
+The city has two rapid transit systems: the U-Bahn and the S-Bahn, as well as an above-ground tram system. Information about the U- and S-Bahn can be found on the website of the RMV.[54]
+
+Nine S-Bahn lines (S1 to S9) connect Frankfurt with the densely populated Rhine Main Region. Most routes have at least 15-minute service during the day, either by one line running every 15 minutes, or by two lines servicing one route at a 30-minute interval. All lines, except line S7, run through the Frankfurt city tunnel and serve the stations Ostendstraße, Konstablerwache, Hauptwache, Taunusanlage and Frankfurt Central Station. When leaving the city the S-Bahn travels above ground. It provides access to the trade fair (S3, S4, S5, S6), the airport (S8, S9), the stadium (S7, S8, S9) and nearby cities such as Wiesbaden, Mainz, Darmstadt, Rüsselsheim, Hanau, Offenbach am Main, Oberursel, Bad Homburg, Kronberg, Friedberg and smaller towns that are on the way.
+The S8/S9 runs 24/7.
+
+The U-Bahn has nine lines (U1 to U9) serving Frankfurt and the larger suburbs of Bad Homburg and Oberursel in the north. The trains that run on the U-Bahn are in fact light rail (Stadtbahn) as many lines travel along a track in the middle of the street instead of underground further from the city centre. The minimum service interval is 2.5 minutes, although the usual pattern is that each line runs at 7.5 to 10-minute intervals, which produce between 3 and 5-minute intervals on city centre tracks shared by more than one line.
+
+Frankfurt has ten tram lines (11, 12, 14 to 21), with trams arriving usually every 10 minutes. Many sections are served by two lines, combining to run at 5-minute intervals during rush-hour. Trams only run above ground and serve more stops than the U-Bahn or the S-Bahn.
+
+A number of bus lines complete the Frankfurt public transport system. Night buses replace U-Bahn and tram services between 1:30 am and 3:30 am.[55] The central junction for the night bus service is Konstablerwache in the city centre, where all night bus lines start and end.
+
+Taxicabs can usually be found outside the major S-Bahn and U-Bahn stations, at the central station, the south station, the airport, the trade fair and in the crowded inner-city shopping streets. The common way to obtain a taxi is to either call a taxi operator or to go to a taxi rank. However, although not the norm, one can hail a passing taxi on the street.
+
+Uber ceased operations in Frankfurt on 9 November 2015 after operating in the city for 18 months.[56]
+
+Deutsche Bahn makes bicycles available for hire through their Call a Bike service. The bicycles are stationed all over the city, including at selected railway stations. They can easily be spotted because of their eye-catching silver-red colour. To rent a specific bike, riders either call a service number to get an unlock code or reserve the bike via the smartphone application. To return the bike, the rider locks it within a designated return area (and calls the service number, if not booked via the app).[57]
+
+Nextbike also makes bicycles available for hire in Frankfurt. They are stationed all over the city. These can be spotted with their blue color scheme.
+
+Cycle rickshaws (velotaxis), a type of tricycle designed to carry passengers in addition to the driver, are also available. These are allowed to operate in pedestrian-only areas and are therefore practical for sightseeing.
+
+Frankfurt has a network of cycle routes. Many long-distance bike routes into the city have cycle tracks that are separate from motor vehicle traffic. A number of roads in the city centre are "bicycle streets" where the cyclist has the right of way and where motorised vehicles are only allowed access if they do not disrupt the cycle users. In addition, cyclists are allowed to ride many cramped one-way streets in both directions. As of 2015[update], 15 percent of citizens used bicycles.[58]
+
+Frankfurt is one of the world's most important financial centres and Germany's financial capital, followed by Munich. Frankfurt was ranked 8th at the International Financial Centers Development Index (2013), 8th at the Worldwide Centres of Commerce Index (2008), 9th at the Global Financial Centres Index (September 2013),[59] 10th at the Global Power City Index (2011), 11th at the Global City Competitiveness Index (2012), 12th at the Innovation Cities Index (2011),[60] 14th at the World City Survey (2011) and 23rd at the Global Cities Index (2012).[61]
+
+The city's importance as a financial centre has risen since the eurozone crisis. Indications are the establishment of two institutions of the European System of Financial Supervisors (European Insurance and Occupational Pensions Authority and European Systemic Risk Board) in 2011 and the Single Supervisory Mechanism by which the European Central Bank was to assume responsibility for specific supervisory tasks related to the financial stability of the biggest and most important Eurozone banks.
+
+According to an annual study by Cushman & Wakefield, the European Cities Monitor (2010), Frankfurt has been one of the top three cities for international companies in Europe, after London and Paris, since the survey started in 1990.[62] It is the only German city considered to be an alpha world city (category 3) as listed by the Loughborough University group's 2010 inventory,[63] which was a promotion from the group's 2008 inventory when it was ranked as an alpha minus world city (category 4).[64]
+
+With over 922 jobs per 1,000 inhabitants, Frankfurt has the highest concentration of jobs in Germany. On work days and Saturdays one million people commute from all over the Rhein-Main-Area.
+
+The city is expected to benefit from international banks relocating jobs from London to Frankfurt as a result of Brexit to retain access to the EU market.[65][66] Thus far, Morgan Stanley, Citigroup Inc., Standard Chartered Plc and Nomura Holdings Inc. announced they would move their EU headquarters to Frankfurt.[66]
+
+Frankfurt is home to two important central banks: the German Bundesbank and the European Central Bank (ECB).[67]
+
+The European Central Bank (Europäische Zentralbank) is one of the world's most important central banks. The ECB sets monetary policy for the Eurozone, consisting of 19 European Union member states that have adopted the Euro (€) as their common currency. From 1998 the ECB Headquarters have been located in Frankfurt, first in the Eurotower at Willy-Brandt-Platz and in two other nearby high-rises. The new Seat of the European Central Bank in the Ostend district, consisting of the former wholesale market hall (Großmarkthalle) and a newly built 185-metre skyscraper, was completed in late 2014. The new building complex was designed to accommodate up to 2,300 ECB personnel. The location is a few kilometres away from the city centre and borders an industrial area as well as the Osthafen (East Harbour), It was primarily chosen because of its large premises which allows the ECB to install security arrangements without high fences.
+
+The city honours the importance of the ECB by officially using the slogan "The City of the Euro" since 1998.
+
+The Deutsche Bundesbank (German Federal Bank), located in Ginnheim, was established in 1957 as the central bank for the Federal Republic of Germany. Until the euro (€) was introduced in 1999, the Deutsche Bundesbank was responsible for the monetary policy of Germany and for the German currency, the Deutsche Mark (DM). The Bundesbank was greatly respected for its control of inflation through the second half of the 20th century. Today the Bundesbank is an integral part of the European System of Central Banks (ESCB) which is formed by all 28 European Union member states.
+
+In 2010, 63 national and 152 international banks had a registered office, including the headquarters of the major German banks, as well as 41 offices of international banks.[6] Frankfurt is therefore known as Bankenstadt ("City of the banks") and nicknamed "Mainhattan" (a portmanteau of the local Main river and Manhattan in New York City) or "Bankfurt". 73,200 people were employed at banks in 2010.
+
+Other major German banks include Frankfurter Volksbank, the second-largest Volksbank in Germany, Frankfurter Sparkasse and old-established private banks such as Bankhaus Metzler, Hauck & Aufhäuser and Delbrück Bethmann Maffei.
+
+Many international banks have a registered or a representative office, e.g., Credit Suisse, UBS, Bank of America, Morgan Stanley, Goldman Sachs, Merrill Lynch, JPMorgan Chase & Co., Bank of China, Banco do Brasil, Itaú Unibanco Société Générale, BNP Paribas, SEB, Royal Bank of Scotland and Barclays.
+
+The Frankfurt Stock Exchange (Frankfurter Wertpapierbörse) began in the 9th century. By the 16th century Frankfurt had developed into an important European hub for trade fairs and financial services. Today the Frankfurt Stock Exchange is by far the largest in Germany, with a turnover of more than 90 percent of the German stock market and is the third-largest in Europe after the London Stock Exchange and the European branch of the NYSE Euronext. The most important stock market index is the DAX, the index of the 30 largest German business companies listed at the stock exchange. The stock exchange is owned and operated by Deutsche Börse, which is itself listed in the DAX. Deutsche Börse also owns the European futures exchange Eurex and clearing company Clearstream. Trading takes place exclusively via the Xetra trading system, with redundant floor brokers taking on the role of market-makers on the new platform.
+
+On 1 February 2012 European Commission blocked the proposed merger of Deutsche Börse and NYSE Euronext. "The merger between Deutsche Börse and NYSE Euronext would have led to a near-monopoly in European financial derivatives worldwide. These markets are at the heart of the financial system and it is crucial for the whole European economy that they remain competitive. We tried to find a solution, but the remedies offered fell far short of resolving the concerns."[69] European competition commissioner, Joaquín Almunia, said.
+
+It is located in the city centre at the Börsenplatz. Deutsche Börse's headquarters are formally registered in Frankfurt but it moved most of its employees to a high-rise called "The Cube" in Eschborn in 2010, primarily due to significantly lower local corporate taxes.
+
+Frankfurt Trade Fair (Messe Frankfurt) has the third-largest exhibition site in the world with a total of 578,000 square metres (6,221,540 square feet). The trade fair premises are located in the western part between Bockenheim, the Westend and the Gallus district. It houses ten exhibition halls with a total of 321,754 square meters (3,463,331 square feet) of space and 96,078 square metres (1,034,175 square feet) of outdoor space.
+
+Hosted in Frankfurt are the Frankfurt Motor Show (Internationale Automobil-Ausstellung – IAA), the world's largest auto show, the Frankfurt Book Fair (Frankfurter Buchmesse), the world's largest book fair, the Ambiente Frankfurt, the world's largest consumer goods fair, the Achema, the world's largest plant engineering fair, and many more like Paperworld, Christmasworld, Beautyworld, Tendence Lifestyle or Light+Building.
+
+Messe Frankfurt GmbH, the owner and operator company, organized 87 exhibitions in 2010, 51 thereof in foreign countries. It is one of the largest trade fair companies with commercial activities in over 150 countries.
+
+A landmark building of the trade fair (and of the whole city) is the Messeturm (the name translates as Fair Trade Tower), which was the tallest building in Europe from 1991 to 1997. It is located on the north-east corner of the trade fair premises at the so-called city entrance. Despite the name it is not used for exhibition but serves as an office tower.
+
+Frankfurt Airport is one of the busiest airports in the world and is also the single largest place of work in Germany with over 500 companies which employ 71,500 people (2010).[70]
+
+The largest company at Frankfurt Airport is Lufthansa, Germany's flag carrier and Europe's largest airline. Lufthansa employs 35,000 people in Frankfurt.[71][72] The Lufthansa Aviation Center (LAC) is the main operation base of Lufthansa at Frankfurt Airport. The airport serves as Lufthansa's primary hub with 157 worldwide destinations (compared to 110 destinations at Munich Airport, Lufthansa's second-largest hub). Lufthansa Cargo is based in Frankfurt and operates its largest cargo center (LCC) at Frankfurt Airport. Lufthansa Flight Training is also based here.
+
+Fraport is the owner and operator of Frankfurt Airport. It is the airport's second-largest employer (19,800 workers in 2010).[73] Fraport also operates other airports worldwide, e.g., King Abdulaziz International Airport in Jeddah, Jorge Chávez International Airport in Lima and Antalya Airport.
+
+Condor is a German airline and part of Thomas Cook Group, based at Frankfurt Airport.
+
+Three of the four largest international accountancy and professional services firms (Big Four) are present.
+
+PricewaterhouseCoopers (PwC) German headquarters are located at Tower 185. KPMG moved its European Headquarters (KPMG Europe LLP) to The Squaire. Deloitte Touche Tohmatsu are present, while Ernst & Young is located in Eschborn.
+
+The three major international credit rating agencies – Standard & Poor's, Moody's and Fitch Ratings – have their German headquarters in Frankfurt.
+
+DWS Investments is the largest investment trust company in Germany and manages €288 billion fund assets. It is one of the 10 largest investment trust companies in the world.[74] Other large investment trust companies are Allianz Global Investors Europe (a division of Allianz SE, and a top-five global active investment manager with €1,933 billion assets under management globally), Union Investment and Deka Investmentfonds.
+
+Many of the largest international management consultancies are represented, including Arthur D. Little, McKinsey & Company, Boston Consulting Group, Booz & Company, Oliver Wyman, Bearing Point, Capgemini, Bain & Company and Roland Berger Strategy Consultants.
+
+Located in Frankfurt are the German headquarters of Jones Lang LaSalle and BNP Paribas Real Estate.
+
+Frankfurt has the highest concentration of lawyers in Germany, with one lawyer per 97 inhabitants (followed by Düsseldorf with a ratio of 1/117 and Munich with 1/124) in 2005.[75]
+
+Most of the large international law firms maintain offices, among them Allen & Overy, Baker & McKenzie, Bird & Bird, Clifford Chance, Cleary Gottlieb Steen & Hamilton, Debevoise & Plimpton, DLA Piper, Freshfields Bruckhaus Deringer, Hogan Lovells, Jones Day, Latham & Watkins, Linklaters, Mayer Brown, Milbank, Tweed, Hadley & McCloy, Norton Rose, Shearman & Sterling, Sidley Austin, SJ Berwin, Skadden, Arps, Slate, Meagher & Flom, Sullivan & Cromwell, K&L Gates, Taylor Wessing and White & Case.
+
+Although it is best known for its banks and financial institutions, Frankfurt is also a centre for media companies. Around 570 companies of the advertising industry and 270 public relations companies are there.
+
+According to a ranking of German FOCUS magazine (November 2007) seven of the 48 largest advertising agencies in Germany are based in Frankfurt, including Havas, Dentsu, McCann-Erickson, Saatchi & Saatchi, JWT, and Publicis.[76]
+
+Frankfurt is home to the German headquarters of Nestlé, the world's largest food company, located in Niederrad. Other important food companies are Ferrero SpA (German headquarters) and Radeberger Gruppe KG, the largest private brewery group in Germany.
+
+The South-Korean automobile manufacturer Kia Motors moved its European headquarters to Frankfurt in 2007. In the same year Italian manufacturer Fiat opened its new German headquarters. The automotive supplier Continental AG has the headquarters and a major manufacturing plant of its Chassis & Safety division (formerly ITT Automotive) located in Frankfurt Rödelheim.
+
+Some of the largest German construction companies have offices, e.g., Bilfinger Berger, Hochtief, Züblin and BAM Deutschland.
+
+Frankfurt has Germany's highest concentration of homeowners. This is partly attributed to the financial sector, but also to its cosmopolitan nature, with expatriates and immigrants representing one fourth of its population. For this reason Frankfurt's property market often operates differently than the rest of the country where the prices are generally flatter.
+
+Frankfurt is home to companies from the chemical, the transportation, the telecommunication and the energy industry. Some of the larger companies are:
+
+Within Frankfurt's urban area are several important companies.
+
+The business centre of Eschborn is located right at Frankfurt's city limits in the west and attracts businesses with significantly lower corporate taxes compared to Frankfurt. Major companies in Eschborn include Ernst & Young, Vodafone Germany, Randstad Holding and VR Leasing. Deutsche Börse moved most of its employees to Eschborn in 2010.
+
+Rüsselsheim is internationally known for its automobile manufacturer Opel, one of the biggest automobile manufacturers in Germany. With 20,000 employees in 2003, Opel was one of the five largest employers in Hesse.
+
+Offenbach am Main is home to the European headquarters of automobile manufacturer Hyundai Motor Company, to the German headquarters of automobile manufacturer Honda, to Honeywell Germany and to Deutscher Wetterdienst, the central scientific agency that monitors weather and meteorological conditions over Germany.
+
+Two DAX companies are located in Bad Homburg vor der Höhe, Fresenius SE & Co. KGaA and Fresenius Medical Care. Other major companies are Hewlett-Packard, Bridgestone, Deutsche Leasing and Basler Versicherungen.
+
+Kronberg im Taunus is home of the German headquarters of automobile manufacturer Jaguar Cars as well as the German headquarters of Accenture.
+
+Lufthansa Systems, a subsidiary of Lufthansa, is located in Kelsterbach.
+
+LSG Sky Chefs, another subsidiary of Lufthansa, is located in Neu-Isenburg.
+
+The German headquarters of Thomas Cook Group are based in Oberursel.
+
+Langen is home to Deutsche Flugsicherung, the German air traffic control.
+
+According to a ranking list (2001) produced by the University of Liverpool, Frankfurt is the richest city in Europe by GDP per capita, followed by Karlsruhe, Paris and Munich.[77]
+
+Frankfurt was voted the 7th in the Mercer Quality of Living Survey by the Mercer Quality of Living Survey (2012),[78] seventh in the Mercer Quality of Living Survey (2010) and 18th at the Economist's World's Most Liveable Cities Survey (2011).[79] According to an annual citizen survey (2010), arranged by the city council, 66 percent inhabitants are satisfied or highly satisfied with the city, while only 6 percent said that they are dissatisfied. Compared to the 1993's survey the number of satisfied inhabitants has grown about 22 percent while the number of dissatisfied inhabitants was reduced by 8 percent. 84 percent of the inhabitants like to live in Frankfurt, 13 percent would rather choose to live somewhere else. 37 percent are satisfied with the public safety (1993: only 9 percent), 22 percent are dissatisfied (1993: 64 percent).[80]
+
+Frankfurt consistently has the highest levels of crime per 100,000 inhabitants in Germany (15.976 crimes per annum in 2008) and is therefore dubbed the German "crime capital".[81] However, this statistic is often criticized[citation needed] because it ignores major factors: It is calculated based on the administrative 680,000-inhabitant figure while the urban area has 2.5 M inhabitants and on weekdays adds another million people[citation needed] (not counting the 53 million passengers passing through the airport each year). The rate for personal safety-relevant crimes such as murder, manslaughter, rape or bodily harm, is 3.4 percent, placing Frankfurt twelfth in the ranking (related to the official 680,000-inhabitant figure) or number 21 (related to the one-million-figure).[82] In 2018, the state of Hesse where Frankfurt lies ranked the third safest state in Germany.[83]
+
+The European Insurance and Occupational Pensions Authority (EIOPA) is an institution of the European Union and part of the European System of Financial Supervisors that was created in response to the financial crisis of 2007–2008. It was established on 1 January 2011.
+
+Frankfurt is one of two locations of the German Federal Financial Supervisory Authority (Bundesanstalt für Finanzdienstleistungsaufsicht, short: BaFin). The BaFin is an independent federal institution and acts as Germany's financial regulatory authority.
+
+Frankfurt is home to the German office of the International Finance Corporation (IFC), which is part of the World Bank Group. The IFC promotes sustainable private sector investment in developing countries.
+
+Frankfurt is one of two sites of the German National Library (Deutsche Nationalbibliothek), the other being Leipzig. The Deutsche Nationalbibliothek is the largest universal library in Germany. Its task, unique in Germany, is to collect, permanently archive, comprehensively document and record bibliographically all German and German-language publications from 1913 on, foreign publications about Germany, translations of German works and the works of German-speaking emigrants published abroad between 1933 and 1945, and to make them available to the public.
+
+Frankfurt is home to multiple trade unions and associations, including:
+
+trade associations include:
+
+Frankfurt is one of Germany's leading tourist destinations. In addition to its infrastructure and economy, its diversity supports a vibrant cultural scene. This blend of attractions led 4.3 million tourists (2012) to visit Frankfurt.[84] The Hotels in central Frankfurt offer 34,000 beds in 228 hotels, of which 13 are luxury hotels and 46 are first-class hotels.[85]
+
+Besides the tourist attractions in central Frankfurt many internationally famous sites are within 80 km (50 mi) of the city, such as:
+
+As a profoundly international city, Frankfurt hosts 92 diplomatic missions (consulates and consulates-general). Worldwide, only New York City and Hamburg are non-capital cities with more foreign representation. The Consulate General of the United States in Eckenheim is the largest American consulate in the world.
+
+Several courts are located in Frankfurt, including:
+
+Two important daily newspapers are published. The conservative Frankfurter Allgemeine Zeitung, also known as FAZ, was founded in 1949 and is the German newspaper with the widest circulation outside of Germany, with its editors claiming to deliver the newspaper to 148 countries every day. The FAZ has a circulation of over 380,000 copies daily. The other important newspaper, the Frankfurter Rundschau, was first published in 1945 and has a daily circulation of over 181,000.
+
+Several magazines also originate from Frankfurt. The local Journal Frankfurt is the best-known magazine for events, parties, and "insider tips". Öko-Test is a consumer-oriented magazine that focuses on ecological topics. Titanic is a well-known and often criticized satirical magazine with a circulation of approximately 100,000.
+
+Frankfurt's first radio station was the Südwestdeutsche Rundfunkdienst AG (Southwest German Broadcast Service), founded in 1924. Its successor service is the public broadcaster Hessischer Rundfunk (Hessian Broadcast Service). It is located at the "Funkhaus am Dornbusch" in the Dornbusch district and is one of the most important radio and television broadcasters in Hesse, with additional studios in Kassel, Darmstadt and Fulda.
+
+Bloomberg TV and RTL Television have regional studios.
+
+Other radio broadcasters include Main FM and Radio X.
+
+From August 1945 to October 2004, the American Forces Network (AFN) had broadcast from Frankfurt. Due to troop reductions the AFN's location has been closed with AFN now broadcasting from Mannheim.
+
+Frankfurt is home to the German office of Reuters, a global news agency.
+
+Frankfurt hosts two universities and several specialist schools. The two business schools are Goethe University Frankfurt's Goethe Business School and Frankfurt School of Finance & Management.
+
+The oldest and best-known university is the Johann Wolfgang Goethe University, with locations in Bockenheim, Westend, and Riedberg, and the university hospital in Niederrad. Goethe Business School is part of the University's House of Finance at Campus Westend. The Business School's Full Time MBA program has over 70% international students.
+
+The Frankfurt University of Applied Sciences was created out of several older organisations in 1971, and offers over 38 study areas, in the arts, sciences, engineering and law. Some of the most important research projects: Planet Earth Simulator, FraLine-IT-School-Service, quantitative analysis of methane in human corpses with the help of a mass spectrometer, software engineering (e.g., fraDesk), analysis of qualitative and quantitative gas in human lungs, long-term studies on photovoltaic modules (to name only a few).
+
+The city is also home to a business school, Frankfurt School of Finance & Management, formerly known as the Hochschule für Bankwirtschaft (Institution of Higher Learning for Banking Economics), with its new campus near Deutsche Nationalbibliothek U-Bahn stop (recently moving from its previous location in the Ostend (Eastend) neighbourhood). In 2001, it became a specialist institution for Economics and Management, or FOM. Frankfurt School is consistently ranked among the best business schools in the world, attributed to its high research output and quality of undergraduate and graduate training.[93]
+
+Frankfurt has the State Institution of Higher Learning for Artistic Education known as the Städelschule, founded in 1817 by Johann Friedrich Städel. It was taken over by the city in 1942 and turned into a state art school.
+
+Music institutions are the Frankfurt University of Music and Performing Arts, and the Hoch Conservatory (Dr. Hoch's Konservatorium) which was founded in 1878. The International Ensemble Modern Academy is a significant institution for the study of contemporary music.[94]
+
+The Sankt Georgen Graduate School of Philosophy and Theology (German:Philosophisch-Theologische Hochschule Sankt Georgen), a private institution with membership in the German Jesuit Association, has been located in Sachsenhausen since 1950.
+
+The city is home to three Max Planck Society institutes: the Max Planck Institute for European History of Law (MPIeR), Max Planck Institute for Biophysics, and the Max Planck Institute for Brain Research.
+
+The Frankfurt Institute for Advanced Studies, sponsored by several institutional and private sources, is involved in theoretical research in physics, chemistry, neuroscience, and computer science.
+
+Frankfurt is host to the Römisch-Germanische-Kommission (RGK), the German Archaeological Institute branch for prehistoric archaeology in Germany and Europe. The RGK is involved in a variety of research projects. Its library, with over 130,000 volumes, is one of the largest specialised archaeological libraries in the world.
+
+Frankfurt schools rank among the best equipped schools nationwide for availability of PCs and other media facilities. In order to assure maintenance and support of the school PCs, the city in cooperation with the University of Applied Sciences launched the project Fraline – IT-Schul-Service, an initiative employing students to provide basic school IT-support.
+
+Frankfurt is home to several professional sports teams. Some of them have won German Championships. E.g. the Skyliners Frankfurt won the German Basketball Championship in 2004 and the German Cup in 2000. Women's side 1. FFC Frankfurt are Germany's record title holders; Eintracht Frankfurt are one-time German champions, five-times winners of the DFB-Pokal, and winners of the UEFA Cup in 1980.
+Frankfurt hosts the following sports teams or clubs:
+
+Frankfurt is host to the classic cycle race Eschborn-Frankfurt City Loop (known as Rund um den Henninger-Turm from 1961 to 2008). The city hosts also the annual Frankfurt Marathon and the Ironman Germany. In addition to the former, it is one of 13 global host locations to the J.P. Morgan Corporate Challenge [6], Germany's biggest corporate sports event. Rhein-Main Eissport Club forms the base of the German bandy community.[7]

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+Francisco Franco Bahamonde (/ˈfræŋkoʊ/, Spanish: [fɾanˈθisko ˈfɾaŋko]; 4 December 1892 – 20 November 1975) was a Spanish general who led the Nationalist forces in overthrowing the Second Spanish Republic during the Spanish Civil War and thereafter ruled over Spain from 1939 to 1975 as a dictator, assuming the title Caudillo. This period in Spanish history, from the Nationalist victory to Franco's death, is commonly known as Francoist Spain or the Francoist dictatorship.
+
+Born in Ferrol, Spain into an upper-class military family, Franco served in the Spanish Army as a cadet in the Toledo Infantry Academy from 1907 to 1910. While serving in Morocco, he rose through the ranks to become brigadier general in 1926, aged 33, becoming the youngest general in Spain. Two years later Franco became the director of the General Military Academy in Zaragoza. As a conservative and monarchist, Franco regretted the abolition of the monarchy and the establishment of the Second Republic in 1931. He was devastated by the closing of his Academy, but nevertheless continued his service in the Republican Army.[1] His career redoubled after the right-wing CEDA and PRR won the 1933 election empowering him to lead the suppression of the 1934 uprising in Asturias. Franco was briefly elevated to Chief of Army Staff before the 1936 election moved the leftist Popular Front into power, relegating him to the Canary Islands. Two years later Franco, after initial reluctance, joined a military coup which, after failing to take Spain, sparked the Spanish Civil War.
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+During the war, he commandeered Spain's colonial army in Africa and after the death of much of the rebel leadership became his faction's only leader, later appointed Generalissimo and Head of State in 1936. He consolidated all nationalist parties into the FET y de las JONS (creating a one-party state). Three years later the Nationalists declared victory which extended Franco's dictatorship over Spain through a period of repression of political opponents. His dictatorship's use of forced labor, concentration camps, and executions led to between 30,000 and 50,000 deaths.[9][10] Combined with wartime killings, this brings the death toll of the White Terror to between 100,000 and 200,000.[11][12] In post-war Spain, Franco ruled with more power than any Spanish leader before or since and developed a cult of personality around his rule by founding the Movimiento Nacional.  During World War II he maintained Spanish neutrality but supported the Axis — whose members Italy and Germany had supported him during the Civil War — in various ways, damaging the country's international reputation.
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+During the start of the Cold War, Franco lifted Spain out of its mid-19th century economic depression through technocratic and economically liberal policies, presiding over a period of rampant growth known as the "Spanish miracle". At the same time, his regime transitioned from being totalitarian to authoritarian with limited pluralism and became a leader in the anti-Communist movement, garnering support from the West, particularly the United States.[13][14] The dictatorship softened and Luis Carrero Blanco became Franco's éminence grise, whose role expanded after Franco struggled with Parkinson's disease in the 1960s. In 1973 Franco resigned as prime minister – separated from the head of state office since 1966 – due to advanced age and illness, but remained in power as the latter and commander-in-chief. Franco died in 1975, aged 82, and was entombed in the Valle de los Caídos. He restored the monarchy in his final years, being succeeded by Juan Carlos as King of Spain, who, in turn, led the Spanish transition to democracy.
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+The legacy of Franco in Spanish history remains controversial as the nature of his dictatorship changed over time. His reign was marked by both brutal repression, with thousands killed, and economic prosperity, which greatly improved the quality of life in Spain. His dictatorial style proved highly adaptable, which enabled wide-sweeping social and economic reform, while consistent pursuits during his reign centered on highly centralised government, authoritarianism, nationalism, national Catholicism, anti-freemasonry, and anti-communism.
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+Francisco Franco Bahamonde was born on 4 December 1892 in the Calle Frutos Saavedra in El Ferrol, Galicia.[15] He was baptised thirteen days later at the military church of San Francisco, with the baptismal name Francisco Paulino Hermenegildo Teódulo;[15] Francisco for his paternal grandfather, Paulino for his godfather, Hermenegildo for his maternal grandmother and godmother, and Teódulo for the saint day of his birth. Franco was born into a seafaring family of Andalusian ancestry.[16][b]
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+After relocating to Galicia, the family was involved in the Spanish Navy, and over the span of two centuries produced naval officers for six uninterrupted generations (including several admirals),[19] down to Franco's father Nicolás Franco y Salgado Araújo (22 November 1855 – 22 February 1942).[20]
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+His mother, María del Pilar Bahamonde y Pardo de Andrade (15 October 1865 – 28 February 1934), was from an upper-middle-class Roman Catholic family. Her father, Ladislao Bahamonde Ortega, was the commissar of naval equipment at the Port of El Ferrol. Franco's parents married in 1890 in the Church of San Francisco in El Ferrol.[21] The young Franco spent much of his childhood with his two brothers, Nicolás and Ramón, and his two sisters, María del Pilar and María de la Paz. His brother Nicolás was naval officer and diplomat who  married María Isabel Pascual del Pobil y Ravello.[22] Ramón was an internationally-known aviator, a Freemason originally with leftist political leanings.[23] He was also the second sibling to die, killed in an air accident on a military mission in 1938.[23]
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+Franco's father was a naval officer who reached the rank of vice admiral (intendente general). When Franco was fourteen, his father moved away to Madrid following a reassignment and ultimately abandoned his family, marrying another woman. While Franco did not suffer any great abuse at his father's hand, he would never overcome his antipathy for his father and largely ignored him for the rest of his life; years after becoming dictator, Franco wrote a brief novel Raza under the pseudonym Jaime de Andrade, whose protagonist is believed by Stanley Payne to represent the idealised man Franco wished his father had been. Conversely, Franco strongly identified with his mother (who always wore widow's black once she realised her husband had abandoned her) and learned from her moderation, austerity, self-control, family solidarity and respect for Catholicism, though he would also inherit his father's harshness, coldness and implacability.[24]
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+Francisco was to follow his father into the Navy, but as a result of the Spanish–American War the country lost much of its navy as well as most of its colonies. Not needing any more officers, the Naval Academy admitted no new entrants from 1906 to 1913. To his father's chagrin, Francisco decided to try the Spanish Army. In 1907, he entered the Infantry Academy in Toledo. At the age of fourteen, Franco was one of the youngest members of his class, with most boys being between sixteen and eighteen. He was short and was bullied for his small size. His grades were average; though his good memory meant he seldom struggled in mental tests, his small stature was a hindrance in physical tests. He would graduate in July 1910 as second lieutenant, coming in at position 251 out of 312, though this may have been less to do with his grades than his small size, young age and reduced physical presence; Stanley Payne observes that by the time Civil War began, Franco had already become a major general and would soon be a generalissimo, while none of his higher-ranking fellow cadets had managed to get beyond the rank of lieutenant-colonel.[25][26] At 19, Franco was promoted to the rank of first lieutenant in June 1912.[27][28] Two years later, he obtained a commission to Morocco. Spanish efforts to occupy their new African protectorate provoked the Second Melillan campaign in 1909 with native Moroccans, the first of a period of Riffian rebellions. Their tactics resulted in heavy losses among Spanish military officers, and also provided an opportunity to earn promotion through merit. It was said that officers would receive either la caja o la faja (a coffin or a general's sash). Franco quickly gained a reputation as a good officer.
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+In 1913, Franco transferred into the newly formed regulares: Moroccan colonial troops with Spanish officers, who acted as shock troops. This transfer into a perilous role may have been decided because Franco failed to win the hand of his first love, Sofía Subirán. The letters between the two were found and she was questioned by journalists.
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+In 1916, aged 23 as a captain, he was shot by enemy machine gun fire. He was badly wounded in the abdomen, specifically the liver, in a skirmish at El Biutz. The physicians of the battle later concluded that his intestines were spared because he inhaled the moment he was shot. In 2008, it was alleged by historian José María Zavala that this injury had left Franco with only one testicle. Zavala cites Ana Puigvert, whose father Antonio Puigvert, was Franco's physician.[29]
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+His recovery was seen by native troops in Africa as a spiritual event – they believed Franco to be blessed with baraka, or protected by God. He was recommended for promotion to major and to receive Spain's highest honour for gallantry, the coveted Cruz Laureada de San Fernando. Both proposals were denied citing the 23-year-old Franco's young age as the reason for denial. Instead Franco received the Cross of Maria Cristina, First Class.[30]
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+With that he was promoted to major at the end of February 1917 at age 24. This made him the youngest major in the Spanish army. From 1917 to 1920, he served in Spain. In 1920, Lieutenant Colonel José Millán Astray, a histrionic but charismatic officer, founded the Spanish Foreign Legion, on similar lines as the French Foreign Legion. Franco became the Legion's second-in-command and returned to Africa. In the Rif War, on 24 July 1921, the poorly commanded and overextended Spanish Army suffered a crushing defeat at Annual from the Republic of the Rif led by the Abd el-Krim brothers. The Legion and supporting units relieved the Spanish enclave of Melilla after a three-day forced march led by Franco. In 1923, by now a lieutenant colonel, he was made commander of the Legion.
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+On 22 October 1923, Franco married María del Carmen Polo y Martínez-Valdès (11 June 1900 – 6 February 1988).[31] Three years later, on 14 September 1926, the couple had a daughter, María del Carmen. Franco would have a close relationship with his daughter and was a proud parent, though his traditionalist attitudes and increasing responsibilities meant he left much of the child-rearing to his wife.[32][33] Following his honeymoon Franco was summoned to Madrid to be presented to King Alfonso XIII.[34] This and other occasions of royal attention would mark him during the Republic as a monarchical officer. Promoted to colonel, Franco led the first wave of troops ashore at Al Hoceima (Spanish: Alhucemas) in 1925. This landing in the heartland of Abd el-Krim's tribe, combined with the French invasion from the south, spelled the beginning of the end for the short-lived Republic of the Rif. Franco's recognition eventually caught up with him, and he was promoted to brigadier general on 3 February 1926. This made him the youngest general in Spain, and perhaps, along with Major-General Joe Sweeney of the Irish Army, one of the youngest generals in Europe.[35] In 1928 Franco was appointed director of the newly created General Military Academy of Zaragoza, a new college for all army cadets, replacing the former separate institutions for young men seeking to become officers in infantry, cavalry, artillery, and other branches of the army. Franco was removed as Director of the Zaragoza Military Academy in 1931; about 95% of his former Zaragoza cadets later came to side with him in the Civil War.
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+The municipal elections of 12 April 1931 were largely seen as plebiscite on the monarchy. The Republican-Socialist alliance failed to win the majority of the municipality cities in Spain, but had a landslide victory in all large cities and in almost all provincial capitals.[36] The monarchists and the army deserted Alfonso XIII and the King decided to leave the country into exile, giving way to the Second Spanish Republic. Although Franco believed that the majority of the Spanish people still supported the crown, and although he regretted the end of the monarchy, he did not object, nor did he challenge the legitimacy of the republic.[37] But the closing of the Academy in June by the provisional War Minister Manuel Azaña was a major setback for Franco and provoked his first clash with the Spanish Republic. Azaña found Franco's farewell speech to the cadets insulting.[38] In his speech Franco stressed the Republic's need for discipline and respect.[39] Azaña entered an official reprimand into Franco's personnel file and for six months Franco was without a post and under surveillance.[38]
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+In December 1931, a new reformist, liberal, and democratic constitution was declared. It included strong provisions enforcing a broad secularisation of the Catholic country, which included the abolishing of Catholic schools and charities, which many moderate committed Catholics opposed.[40] At this point once the constituent assembly had fullfilled its mandate of approving a new constitution, it should have[clarification needed] arranged for regular parliamentary elections and adjourned. Fearing the increasing popular opposition, the Radical and Socialist majority postponed the regular elections, therefore prolonging their way in power for two more years. This way the republican government of Manuel Azaña initiated numerous reforms to what in their view would "modernize" the country.[41]
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+Franco was a subscriber to the journal of Acción Española, a monarchist organisation, and a firm believer in a supposed Jewish-Masonic-Bolshevik conspiracy, or contubernio (filthy cohabitation).  The conspiracy suggested that Jews, Freemasons, Communists, and other leftists alike sought the destruction of Christian Europe, with Spain the principal target.[42]
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+On 5 February 1932, Franco was given a command in A Coruña. Franco avoided involvement in José Sanjurjo's attempted coup that year, and even wrote a hostile letter to Sanjurjo expressing his anger over the attempt. As a result of Azaña's military reform, in January 1933 Franco was relegated from first to 24th in the list of brigadiers. The same year, on 17 February he was given the military command of the Balearic Islands. The post was above his rank, but Franco was still angered that he was purposely stuck in positions he disliked. It was quite common for conservative officers to be moved or demoted.
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+In 1932 the Jesuits who were in charge of the best schools throughout the country were banned and had all their property confiscated. The army was further reduced. Landowners were expropriated. Home rule was granted to Catalonia, with a local parliament and a president of its own. [41] In June 1933 Pope Pius XI issued the encyclical Dilectissima Nobis, "On Oppression of the Church of Spain", raising his voice against the persecution of the Catholic Church in Spain.[43]
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+The elections held in October 1933 resulted in a centre-right majority. The political party with the most votes was the Confederación Español de Derechas Autónomas ("CEDA"), but president Alcalá-Zamora declined to invite the leader of the CEDA, Gil Robles, to form a government. Instead he invited the Radical Republican Party's Alejandro Lerroux to do so. Despite receiving the most votes, CEDA was denied cabinet positions for nearly a year.[44] After a year of intense pressure, CEDA, the largest party in the congress, was finally successful in forcing the acceptance of three ministries. The entrance of CEDA in the government, despite being normal in a parliamentary democracy, was not well accepted by the left.  The Socialists triggered an insurrection that they had been preparing for nine months.[45] A general strike was called by the UGT and the PSOE in the name of the Alianza Obrera. The issue was that the Left Republicans identified the Republic not with democracy or constitutional law but a specific set of left-wing policies and politicians. Any deviation, even if democratic, was seen as treasonous.[46] A Catalan state was proclaimed by Catalan nationalist leader Lluis Companys, but it lasted just ten hours. Despite an attempt at a general stoppage in Madrid, other strikes did not endure. This left Asturian strikers to fight alone.[47]
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+In several mining towns in Asturias, local unions gathered small arms and were determined to see the strike through. It began on the evening of 4 October, with the miners occupying several towns, attacking and seizing local Civil and Assault Guard barracks.[48] Thirty four priests, six young seminarists with ages between 18 and 21, and several businessmen and civil guards were summarily executed by the revolutionaries in Mieres and Sama, 58 religious buildings including churches, convents and part of the university at Oviedo were burned and destroyed.[49][50] Franco, already General of Division and aide to the war minister, Diego Hidalgo, was put in command of the operations directed to suppress the violent insurgency. Troops of the Spanish Army of Africa carried this out, with General Eduardo López Ochoa as commander in the field. After two weeks of heavy fighting (and a death toll estimated between 1,200 and 2,000), the rebellion was suppressed.
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+The insurgency in Asturias sparked a new era of violent anti-Christian persecutions, initiated the practice of atrocities against the clergy,[50] and sharpened the antagonism between Left and Right. Franco and López Ochoa (who, prior to the campaign in Asturias, had been seen as a left-leaning officer)[51] emerged as officers prepared to use "troops against Spanish civilians as if they were a foreign enemy".[52] Franco described the rebellion to a journalist in Oviedo as, "a frontier war and its fronts are socialism, communism and whatever attacks civilisation to replace it with barbarism." Though the colonial units sent to the north by the government at Franco's recommendation[53] consisted of the Spanish Foreign Legion and the Moroccan Regulares Indigenas, the right-wing press portrayed the Asturian rebels as lackeys of a foreign Jewish-Bolshevik conspiracy.[54]
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+With this rebellion against established political legitimate authority, the Socialists showed identical repudiation of representative institutional system that anarchists had practiced.[55] The Spanish historian Salvador de Madariaga, an Azaña supporter, and an exhiled vocal opponent of Francisco Franco is the author of a sharp critical reflection against the participation of the left in the revolt: “The uprising of 1934 is unforgivable. The argument that Mr Gil Robles tried to destroy the Constitution to establish fascism was, at once, hypocritical and false. With the rebellion of 1934, the Spanish left lost even the shadow of moral authority to condemn the rebellion of 1936.” [56]
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+At the start of the Civil War, López Ochoa was assassinated. Some time after these events, Franco was briefly commander-in-chief of the Army of Africa (from 15 February onwards), and from 19 May 1935, on, Chief of the General Staff.
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+In the end of 1935 President Alcalá-Zamora manipulated a petty-corruption issue into a major scandal in parliament, and eliminated Alejandro Lerroux, the head of the Radical Republican Party, from premiership. Subsequently, Alcalá-Zamora vetoed the logical replacement, a majority center-right coalition, led by the CEDA, which would reflect the composition of the parliament. He then arbitrarily appointed an interim prime minister and after a short period announced the dissolution of parliament and new elections.[57]
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+Two wide coalitions formed: the Popular Front on the left, ranging from Republican Union to Communists, and the Frente Nacional on the right, ranging from the centre radicals to the conservative Carlists. On 16 February 1936 the elections ended in a virtual draw, but in the evening leftist mobs started to interfere in the balloting and in the registration of votes distorting the results.[58][59] Stanley G. Payne claims that the process was a major electoral fraud, with widespread violation of the laws and the constitution.[60] In line with Payne's point of view, in 2017 two Spanish scholars, Manuel Álvarez Tardío and Roberto Villa García published the result of a major research work where they concluded that the 1936 elections were rigged.[61][62]
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+On 19 February the cabinet presided by Portela Valladares resigned, with a new cabinet being quickly set up, composed chiefly of members of the Republican Left and the Republican Union and presided by Manuel Azaña.[63]
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+José Calvo Sotelo, who acquired anti-communism as the axis of his parliamentary speeches, became the speaker of violent propaganda—advocating for a military coup d'état; formulating a catastrophist discourse of a dichotomous choice between "communism" or a markedly totalitarian "National" State, setting the mood of the masses for a military rebellion.[64] The diffusion of the myth about an alleged Communist coup d'état as well a pretended state of "social chaos" became pretexts for a coup.[64] Franco himself along with General Emilio Mola had stirred an Anti-Communist campaign in Morocco.[64]
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+At the same time PSOE's left-wing socialists became more radical. Julio Álvarez del Vayo talked about "Spain's being converted into a socialist Republic in association with the Soviet Union". Francisco Largo Caballero declared that "the organized proletariat will carry everything before it and destroy everything until we reach our goal".[65] The country rapidly descended into anarchy. Even the staunch socialist Indalecio Prieto, at a party rally in Cuenca in May 1936, complained: "we have never seen so tragic a panorama or so great a collapse as in Spain at this moment. Abroad Spain is classified as insolvent. This is not the road to socialism or communism but to desperate anarchism without even the advantage of liberty".[65]
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+On 23 February Franco was sent to the Canary Islands to serve as the islands' military commander, an appointment perceived by him as a destierro (banishment).[66] Meanwhile, a conspiracy led by General Mola was taking shape.
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+Interested in the parliamentary immunity granted by a seat at the Cortes, Franco intended to stand as candidate of the Right Bloc alongside José Antonio Primo de Rivera for the by-election in the province of Cuenca programmed for 3 May 1936, after the results of the February 1936 election were annulled in the constituency. But Primo de Rivera refused to run alongside a military officer (and Franco in particular) and Franco himself ultimately desisted on 26 April, one day before the decision of the election authority.[67] By that time, PSOE politician Indalecio Prieto already deemed Franco as "possible caudillo for a military uprising".[67]
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+The disenchantment with Azaña's rulling continued to grow and was dramatically voiced by Miguel de Unamuno, a republican and one of Spain's most respected intellectuals, who in June 1936 told a reporter who published his statement in El Adelanto that President Manuel Azaña should "commit suicide as a patriotic act".[68]
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+In June 1936, Franco was contacted and a secret meeting was held within La Esperanza forest on Tenerife to discuss starting a military coup.[69] An obelisk commemorating this historic meeting was erected at the site in a clearing at Las Raíces.[70]
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+Outwardly, Franco maintained an ambiguous attitude until nearly July. On 23 June 1936, he wrote to the head of the government, Casares Quiroga, offering to quell the discontent in the Spanish Republican Army, but received no reply. The other rebels were determined to go ahead con Paquito o sin Paquito (with Paquito or without Paquito; Paquito being a diminutive of Paco, which in turn is short for Francisco), as it was put by José Sanjurjo, the honorary leader of the military uprising. After various postponements, 18 July was fixed as the date of the uprising. The situation reached a point of no return and, as presented to Franco by Mola, the coup was unavoidable and he had to choose a side. He decided to join the rebels and was given the task of commanding the Army of Africa. A privately owned DH 89 De Havilland Dragon Rapide, flown by two British pilots, Cecil Bebb and Hugh Pollard,[71] was chartered in England on 11 July to take Franco to Africa.
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+The coup underway was precipitated by the assassination of the right-wing opposition leader Calvo Sotelo in retaliation for the murder of assault guard José Castillo, which had been committed by a group headed by a civil guard and composed of assault guards and members of the socialist militias.[72] On 17 July, one day earlier than planned, the Army of Africa rebelled, detaining their commanders. On 18 July, Franco published a manifesto[73] and left for Africa, where he arrived the next day to take command.
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+A week later the rebels, who soon called themselves the Nationalists, controlled a third of Spain; most naval units remained under control of the Republican loyalist forces, which left Franco isolated. The coup had failed in the attempt to bring a swift victory, but the Spanish Civil War had begun. The revolt was remarkably devoid of any particular ideology.[74] The major goal was to put an end to anarchical disorder.[75] Franco himself certainly detested communism, but had no commitment to any ideology: his stand was motivated not by foreign fascism but by Spanish tradition and patriotism.[75]
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+The Spanish Civil War began in July 1936 and officially ended with Franco's victory in April 1939, leaving 190,000[76] to 500,000[77] dead. Despite the Non-Intervention Agreement of August 1936, the war was marked by foreign intervention on behalf of both sides, leading to international repercussions. The nationalist side was supported by Fascist Italy, which sent the Corpo Truppe Volontarie, and later by Nazi Germany, which assisted with the Condor Legion. They were opposed by the Soviet Union and communists, socialists, and anarchists within Spain. The United Kingdom and France strictly adhered to the arms embargo,[citation needed] provoking dissensions within the French Popular Front coalition which was led by Léon Blum, but the Republican side was nonetheless supported by the Soviet Union and volunteers who fought in the International Brigades (see for example Ken Loach's Land and Freedom).
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+Some historians, such as Ernst Nolte, have considered that Adolf Hitler and Joseph Stalin used the Spanish Civil war as a testing ground for modern warfare,[citation needed] being quickly set up and that the Spanish Civil War, along with World War II, to be part of a European Civil War which lasted from 1936 to 1945 and was mainly characterised as a left/right ideological conflict. This interpretation has not been accepted by most historians,[who?] who consider the Spanish Civil War and the Second World War to be two distinct conflicts. Among other things, they point to the political heterogeneity on both sides (See Spanish Civil War: other factions) and criticise a monolithic interpretation, which overlooks the local nuances of Spanish history.
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+Following 18 July 1936 pronunciamiento, Franco assumed the leadership of the 30,000 soldiers of the Spanish Army of Africa. The first days of the insurgency were marked by a serious need to secure control over the Spanish Moroccan Protectorate. On one side, Franco had to win the support of the natives and their (nominal) authorities, and, on the other, had to ensure his control over the army. His method was the summary execution of some 200 senior officers loyal to the Republic (one of them his own cousin). His loyal bodyguard was shot by Manuel Blanco.[78] Franco's first problem was how to move his troops to the Iberian Peninsula, since most units of the Navy had remained in control of the Republic and were blocking the Strait of Gibraltar. He requested help from Benito Mussolini, who responded with an unconditional offer of arms and planes; in Germany Wilhelm Canaris, the head of the Abwehr military intelligence, persuaded Hitler to support the Nationalists. From 20 July onward Franco was able, with a small group of 22 mainly German Junkers Ju 52 aircraft, to initiate an air bridge to Seville, where his troops helped to ensure the rebel control of the city. Through representatives, he started to negotiate with the United Kingdom, Germany, and Italy for more military support, and above all for more aircraft. Negotiations were successful with the last two on 25 July and aircraft began to arrive in Tetouan on 2 August. On 5 August Franco was able to break the blockade with the newly arrived air support, successfully deploying a ship convoy with some 2,000 soldiers.
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+On the Republican side, in July 26, just eight days after the revolt had started, an international communist conference was held at Prague to arrange plans to help the Republican Government. It decide to raise an international brigade of 5,000 men and a fund of 1 billion francs to be administered by a commission where Largo Caballero and Dolores Ibárruri had prominent roles.[79] At the same time communist parties throughout the world quicly launched a full scale propaganda campaign in support of the Popular Front. The Communist International immediately reinforced its activity, sending to Spain its leader Georgi Dimitrov, and Palmiro Togliatti the chief of the Communist Party of Italy.[80][81] From August onward, aid from the Soviet Union began; over one ship per day arrived at Spain's Mediterranean ports carrying munitions, rifles, machine guns, hand grenades, artillery, trucks. With the cargo came Soviet agents, technicians, instructors and propagandists.[80]
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+The Communist International immediately started to organize the International Brigades with great care to conceal or minimize the communist character of the enterprise and to make it appear as a campaign on behalf of progressive democracy.[80] Attractive misleading names were deliberately chosen, such as "Garibaldi" in Italy or "Abraham Lincoln" in the United States.[80]
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+In early August, the situation in western Andalusia was stable enough to allow Franco to organise a column (some 15,000 men at its height), under the command of then Lieutenant-Colonel Juan Yagüe, which would march through Extremadura towards Madrid. On 11 August Mérida was taken, and on 15 August Badajoz, thus joining both nationalist-controlled areas. Additionally, Mussolini ordered a voluntary army, the Corpo Truppe Volontarie (CTV) of fully motorised units (some 12,000 Italians), to Seville, and Hitler added to them a professional squadron from the Luftwaffe (2JG/88) with about 24 planes. All these planes had the Nationalist Spanish insignia painted on them, but were flown by Italian and German nationals. The backbone of Franco's aviation in those days was the Italian SM.79 and SM.81 bombers, the biplane Fiat CR.32 fighter and the German Junkers Ju 52 cargo-bomber and the Heinkel He 51 biplane fighter.
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+On 21 September, with the head of the column at the town of Maqueda (some 80 km away from Madrid), Franco ordered a detour to free the besieged garrison at the Alcázar of Toledo, which was achieved on 27 September. This controversial decision gave the Popular Front time to strengthen its defenses in Madrid and hold the city that year, but with Soviet support.[82] Kennan alleges that, once Stalin had decided to assist the Spanish Republicans, the operation was put in place with remarkable speed and energy. The first load of arms and tanks arrived as early as 26 September and was secretly unloaded at night. Advisers accompanied the armaments. Soviet officers were in effective charge of military operations on the Madrid front. Kennan believes that this operation was originally conducted in good faith with no other purpose than saving the Republic.[83] Effort was made to encourage the Spanish Communist Party to seize power,[84] but the holding of Alcázar was an important morale and propaganda success for the Nationalists, because it is clear that Hitler's primary aim was not a Franco victory but to prolong the war by the active intervention of the Soviet Government as well as that of Italy, Britain, and France in the Civil War.[85]
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+Hitler's policy for Spain was shrewd and pragmatic. His instructions were clear: "A hundred per cent Franco's victory was not desirable from a German Point of view; rather were we interested in a continuance of the war and in the keeping up of the tension in the Mediterranean."[86] Hitler wanted to help Franco just enough to gain his gratitude and to prevent the side supported by the Soviet Union from winning, but not large enough to give the Caudillo a quick victory.[87]
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+By February 1937 the Soviet Union's military help started to taper off, to be replaced by limited economic aid. A more likely motive was Stalin's instinct for self-preservation;  the Spanish Civil War had aroused a spirit of heroism in support of freedom more in line with Trotskyism, and such ideas might be exported to the Soviet Union. Further proof of this is that Modin stated that Stalin decided to attack the extreme Left, particularly Trotskyites and militants of the POUM before liquidating Franco.[88] Those who had served in Spain were tainted in Stalin's view and were singled out for harshness in the purges and were virtually all eliminated. The defector Orlov, who worked for the NKVD in Spain, confirms that he was told by a Soviet general, whom Orlov did not want to name, that when the general returned to Moscow to seek further instructions, he was told that the Politburo had adopted a new line towards Spain. Until then, the policy of the Politburo was to assist Republican Spain by supplying armaments, Soviet pilots, and tanks to bring about a speedy victory over Franco, but now the Politburo had revised its strategy. Stalin had come to the conclusion that "it would be more advantageous to the Soviet Union if neither of the warring camps gained proponderant strength, and if the war in Spain dragged on as long as possible and thus tied up Hitler for a long time." The general who informed Orlov of this was shocked by the Machiavellian calculation of the Politburo which, in its desire to obtain time, wanted the Spanish people to bleed as long as possible.[89]
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+The designated leader of the uprising, General José Sanjurjo, died on 20 July 1936, in a plane crash. In the nationalist zone, "political life ceased."[90] Initially, only military command mattered: this was divided into regional commands (Emilio Mola in the North, Gonzalo Queipo de Llano in Seville commanding Andalusia, Franco with an independent command, and Miguel Cabanellas in Zaragoza commanding Aragon). The Spanish Army of Morocco was itself split into two columns, one commanded by General Juan Yagüe and the other commanded by Colonel José Varela.
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+From 24 July a coordinating junta was established, based at Burgos. Nominally led by Cabanellas, as the most senior general,[91] it initially included Mola, three other generals, and two colonels; Franco was later added in early August.[92] On 21 September it was decided that Franco was to be commander-in-chief (this unified command was opposed only by Cabanellas),[93] and, after some discussion, with no more than a lukewarm agreement from Queipo de Llano and from Mola, also head of government.[94] He was, doubtlessly, helped to this primacy by the fact that, in late July, Hitler had decided that all of Germany's aid to the nationalists would go to Franco.[95]
+
+Mola had been somewhat discredited as the main planner of the attempted coup that had now degenerated into a civil war, and was strongly identified with the Carlist monarchists and not at all with the Falange, a party with Fascist leanings and connections ("phalanx", a far-right Spanish political party founded by José Antonio Primo de Rivera), nor did he have good relations with Germany. Queipo de Llano and Cabanellas had both previously rebelled against the dictatorship of General Miguel Primo de Rivera and were therefore discredited in some nationalist circles, and Falangist leader José Antonio Primo de Rivera was in prison in Alicante (he would be executed a few months later). The desire to keep a place open for him prevented any other Falangist leader from emerging as a possible head of state. Franco's previous aloofness from politics meant that he had few active enemies in any of the factions that needed to be placated, and he had also cooperated in recent months with both Germany and Italy.[96]
+
+On 1 October 1936, in Burgos, Franco was publicly proclaimed as Generalísimo of the National army and Jefe del Estado (Head of State).[97] When Mola was killed in another air accident a year later on 2 June 1937 (which some believe was an assassination), no military leader was left from those who organized the conspiracy against the Republic between 1933 and 1935.[98]
+
+Franco personally guided military operations from this time until the end of the war. Franco himself was not a strategic genius but he was very effective at organisation, administration, logistics and diplomacy.[99] After the failed assault on Madrid in November 1936, Franco settled on a piecemeal approach to winning the war, rather than bold maneuvering. As with his decision to relieve the garrison at Toledo, this approach has been subject of some debate: some of his decisions, such as in June 1938 when he preferred to head for Valencia instead of Catalonia, remain particularly controversial from a military viewpoint. Valencia, Castellon and Alicante saw the last Republican troops defeated by Franco.
+
+Although both Germany and Italy provided military support to Franco, the degree of influence of both powers on his direction of the war seems to have been very limited. Nevertheless, the Italian troops, despite not always being effective, were present in most of the large operations in large numbers, while the German aircraft helped the Nationalist air force dominate the skies for most of the war.
+
+Franco's direction of the German and Italian forces was limited, particularly in the direction of the Condor Legion, but he was by default their supreme commander, and they rarely made decisions on their own. For reasons of prestige it was decided to continue assisting Franco until the end of the war, and Italian and German troops paraded on the day of the final victory in Madrid.[100]
+
+The Nationalist victory could be accounted for by various factors:[101]
+
+The Nazis were disappointed with Franco's resistance to installing fascism. Historian James S. Corum states:
+
+Robert H. Whealey provides more detail:
+
+From 1937 to 1948 the Franco regime was a hybrid as Franco fused the ideologically incompatible national-syndicalist Falange ("Phalanx", a fascist Spanish political party founded by José Antonio Primo de Rivera) and the Carlist monarchist parties into one party under his rule, dubbed Falange Española Tradicionalista y de las Juntas de Ofensiva Nacional-Sindicalista (FET y de las JONS), which became the only legal party in 1939. Unlike some other fascist movements, the Falangists had developed an official program in 1934, the "Twenty-Seven Points".[106] In 1937, Franco assumed as the tentative doctrine of his regime 26 out of the original 27 points.[107] Franco made himself jefe nacional (National Chief) of the new FET (Falange Española Tradicionalista; Traditionalist Spanish Phalanx) with a secretary, Junta Political and National Council to be named subsequently by himself. Five days later (24 April) the raised-arm salute of the Falange was made the official salute of the Nationalist regime.[108] In 1939 the personalist style heavily predominated, with ritualistic invocations of "Franco, Franco, Franco."[109] The Falangists' hymn, Cara al Sol, became the semi-national anthem of Franco's not-yet-established regime.
+
+This new political formation appeased the pro-German Falangists while tempering them with the anti-German Carlists. Franco's brother-in-law Ramón Serrano Súñer, who was his main political advisor, was able to turn the various parties under Franco against each other to absorb a series of political confrontations against Franco himself. Franco expelled the original leading members of both the Carlists (Manuel Fal Condé) and the Falangists (Manuel Hedilla) to secure his political future. Franco also appeased the Carlists by exploiting the Republicans' anti-clericalism in his propaganda, in particular concerning the "Martyrs of the war". While the Republican forces presented the war as a struggle to defend the Republic against fascism, Franco depicted himself as the defender of "Catholic Spain" against "atheist communism".
+
+By early 1939 only Madrid (see History of Madrid) and a few other areas remained under control of the government forces. On 27 February Chamberlain's Britain and Daladier's France officially recognised the Franco regime. On 28 March 1939, with the help of pro-Franco forces inside the city (the "fifth column" General Mola had mentioned in propaganda broadcasts in 1936), Madrid fell to the Nationalists. The next day, Valencia, which had held out under the guns of the Nationalists for close to two years, also surrendered. Victory was proclaimed on 1 April 1939, when the last of the Republican forces surrendered. On the same day, Franco placed his sword upon the altar of a church and in a vow, promised that he would never again take up his sword unless Spain itself was threatened with invasion.
+
+Although Germany had recognised the Franco Government, Franco's policy towards Germany was extremely cautious until spectacular German victories at the beginning of the Second World War. An early indication that Franco was going to keep his distance from Germany soon proved true.[85] A rumoured state visit by Franco to Germany did not take place and a further rumour of a visit by Goering to Spain, after he had enjoyed a cruise in the Western Mediterranean, again did not materialise. Instead Goering had to return to Berlin.[110] This proved how right Eden was when he said "Whatever the final outcome of the strife ... the Spanish people will continue to display that proud independence, that arrogant individualism which is a characteristic of the race. There are twenty-four million reasons why Spain will never for long be dominated by the forces or controlled by the advice of any foreign power."[111]
+
+During the Civil War and in the aftermath, a period known as the White Terror took place. This saw mass executions of Republican and other Nationalist enemies, standing in contrast to the war-time Red Terror. Historical analysis and investigations estimate the number of executions by the Franco regime during this time to be between 100,000 and 200,000 dead.
+
+Stanley G. Payne approximates 50,000 executions by the Republicans and at least 70,000 executions by the Nationalists during the civil war,[77][2][112] with the victory being followed by a further 30,000 executions by the Nationalists.[2] Recent searches conducted with parallel excavations of mass graves in Spain (in particular by the Association for the Recovery of Historical Memory, ARMH) estimate the total of people executed after the civil war between 15,000 and 35,000.[3]
+
+Julián Casanova Ruiz, nominated in 2008 among the experts in the first judicial investigation (conducted by judge Baltasar Garzón) against the Francoist crimes,[113] as well as historians Josep Fontana and Hugh Thomas, estimate the deaths in the White Terror to be around 150,000 in total.[4][114][5][6] According to Paul Preston, 150,000 wartime civilian executions took place in the Francoist area, as well as 50,000 in the Republican area, in addition to 20,000 civilians executed by the Franco regime after the end of the war.[115][c] According to Helen Graham, the Spanish working classes became to the Francoist project what the Jews were to the German Volksgemeinschaft.[117]
+
+According to Gabriel Jackson and Antony Beevor, the number of victims of the "White Terror" (executions and hunger or illness in prisons) only between 1939 and 1943 was 200,000.[100] Beevor "reckons Franco's ensuing 'white terror' claimed 200,000 lives. The 'red terror' had already killed 38,000."[118] Julius Ruiz concludes that "although the figures remain disputed, a minimum of 37,843 executions were carried out in the Republican zone with a maximum of 150,000 executions (including 50,000 after the war) in Nationalist Spain."[119]
+
+Despite the end of the war, guerrilla resistance to Franco, known as "the Maquis", occurred in the Pyrenees, carrying out sabotage and robberies against the Francoist regime. Several exiled Republicans also fought in the French resistance against the German occupation in Vichy France during World War II. In 1944, a group of republican veterans from the French resistance invaded the Val d'Aran in northwest Catalonia, but were quickly defeated. The activities of the Maquis continued well into the 1950s.
+
+The end of the war led to hundreds of thousands of exiles, mostly to France, but also to Mexico, Chile, Cuba, and the United States.[120] On the other side of the Pyrenees, refugees were confined in internment camps in France, such as Camp Gurs or Camp Vernet, where 12,000 Republicans were housed in squalid conditions (mostly soldiers from the Durruti Division[121]). The 17,000 refugees housed in Gurs were divided into four categories: Brigadists, pilots, Gudaris and ordinary "Spaniards". The Gudaris (Basques) and the pilots easily found local backers and jobs, and were allowed to quit the camp, but the farmers and ordinary people, who could not find relations in France, were encouraged by the French government, in agreement with the Francoist government, to return to Spain. The great majority did so and were turned over to the Francoist authorities in Irún. From there they were transferred to the Miranda de Ebro camp for "purification" according to the Law of Political Responsibilities.
+
+After the proclamation by Marshal Philippe Pétain of the Vichy France regime, the refugees became political prisoners, and the French police attempted to round up those who had been liberated from the camp. Along with other "undesirables", they were sent to the Drancy internment camp before being deported to Nazi Germany. 5,000 Spaniards thus died in Mauthausen concentration camp.[122] The Chilean poet Pablo Neruda, who had been named by the Chilean President Pedro Aguirre Cerda special consul for immigration in Paris, was given responsibility for what he called "the noblest mission I have ever undertaken": shipping more than 2,000 Spanish refugees, who had been housed by the French in squalid camps, to Chile on an old cargo ship, the Winnipeg.[123]
+
+In September 1939 World War II began. On 23 October 1940, Hitler and Franco met in Hendaye in France to discuss the possibility of Spain's entry on the side of the Axis. Franco's demands, including supplies of food and fuel, as well as Spanish control of Gibraltar and French North Africa, proved too much for Hitler. At the time Hitler did not want to risk damaging his relations with the new Vichy French government. (An oft-cited remark attributed to Hitler is that the German leader said that he would rather have some of his own teeth extracted than to have to personally deal further with Franco.)[124][125] Franco had received important support from Adolf Hitler and Benito Mussolini during the Spanish Civil War, and he had signed the Anti-Comintern Pact. He described Spain as part of the Axis in official documents[citation needed], while offering various kinds of support to Italy and Germany. He allowed Spanish soldiers to volunteer to fight in the German Army against the Soviet Union (the Blue Division), but forbade Spaniards to fight in the West against the democracies. Franco's common ground with Hitler was particularly weakened by Hitler's propagation of Nazi mysticism and his attempts to manipulate Christianity, which went against Franco's fervent commitment to defending Catholicism.[126] Contributing to the disagreement was an ongoing dispute over German mining rights in Spain. Some historians argue that Franco made demands he knew Hitler would not accede to, in order to stay out of the war. Other historians argue that Franco, as the leader of a destroyed and bankrupt country in chaos following a brutal three-year civil war, simply had little to offer the Axis and that the Spanish armed forces were not ready for a major war. It has also been suggested that Franco decided not to join the war after the resources he requested from Hitler in October 1940 were not forthcoming.[127]
+
+According to some scholars, after the Fall of France in June 1940, Spain did adopt a pro-Axis stance (for example, German and Italian ships and U-boats were allowed to use Spanish naval facilities) before returning to a more neutral position in late 1943 when the tide of the war had turned decisively against the Axis Powers, and Italy had changed sides. Franco was initially keen to join the war before the UK was defeated.[128]
+
+In the winter of 1940–41 Franco toyed with the idea of a "Latin Bloc" formed by Spain, Portugal, Vichy France, the Vatican and Italy, without much consequence.[129] Franco had cautiously decided to enter the war on the Axis side in June 1940, and to prepare his people for war, an anti-British and anti-French campaign was launched in the Spanish media that demanded French Morocco, Cameroon and Gibraltar.[130] On 19 June 1940, Franco pressed along a message to Hitler saying he wanted to enter the war, but Hitler was annoyed at Franco's demand for the French colony of Cameroon, which had been German before World War I, and which Hitler was planning on taking back for Plan Z.[131] Franco seriously considered blocking allied access to the Mediterranean Sea by invading British-held Gibraltar,[124] but he abandoned the idea after learning that the plan would have likely failed due to Gibraltar being too heavily defended. In addition, declaring war on the UK and its allies would no doubt give them an  opportunity to capture both the Canary Islands and Spanish Morocco, as well as possibly launch an invasion of mainland Spain itself.[124][132] Franco was aware that his air force would be defeated if going into action against the Royal Air Force, and the Royal Navy would be able to blockade Spain to prevent imports of crucial materials such as oil. Spain depended on oil imports from the United States, which were almost certain to be cut off if Spain formally joined the Axis. Franco and Serrano Suñer held a meeting with Mussolini and Ciano in Bordighera, Italy on 12 February 1941.[133] Mussolini affected not to be interested in Franco's help due to the defeats his forces had suffered in North Africa and the Balkans, and he even told Franco that he wished he could find any way to leave the war. When the invasion of the Soviet Union began on 22 June 1941, Franco's foreign minister Ramón Serrano Suñer immediately suggested the formation of a unit of military volunteers to join the invasion.[citation needed] Volunteer Spanish troops (the División Azul, or "Blue Division") fought on the Eastern Front under German command from 1941 to 1944. Some historians have argued that not all of the Blue Division were true volunteers and that Franco expended relatively small but significant resources to aid the Axis powers' battle against the Soviet Union.
+
+Franco was initially disliked by Cuban President Fulgencio Batista, who, during World War II, suggested a joint U.S.-Latin American declaration of war on Spain to overthrow Franco's regime.[134] Hitler may not have really wanted Spain to join the war, as he needed neutral harbors to import materials from countries in Latin America and elsewhere. In addition Hitler felt Spain would be a burden as it would be dependent on Germany for help. By 1941 Vichy French forces were proving their effectiveness in North Africa, reducing the need for Spanish help, and Hitler was wary about opening up a new front on the western coast of Europe as he struggled to reinforce the Italians in Greece and Yugoslavia. Franco signed a revised Anti-Comintern Pact on 25 November 1941. Spain continued to import[clarification needed] war materials and trade wolfram with Germany until August 1944 when the Germans withdrew from the Spanish frontier.[127]
+
+Spanish neutrality during World War II was appreciated and publicly acknowledged by leading Allied statesmen.[135] In November 1942 President Roosevelt wrote to General Franco: "...your nation and mine are friends in the best sense of the word."[136] In May 1944 Winston Churchill stated in the House of Commons: "in the dark days of the war the attitude of the Spanish Government in not giving our enemies passage through Spain was extremelly helpful to us...I must say that I shall always consider that a service was rendered...by Spain, not only to the United Kingdom  and to the British Empire and Commonwealth, but to the cause of the United Nations."[136] Similar gratitude was also expressed by the Provisional French Government.[136] Franco interposed no obstacle to Britain's construction of a big air base extending out of Gibraltar into Spanish territorial waters, and welcomed the Anglo-American landings in North Africa. Moreover, Spain did not intern any of the 1,200 American airmen who were forced to land in the country, but gave them shelter and helped them to leave.[136]
+
+After the war, the Spanish government tried to destroy all evidence of its cooperation with the Axis. In 2010 documents were discovered showing that on 13 May 1941, Franco ordered his provincial governors to compile a list of Jews while he negotiated an alliance with the Axis powers.[137] Franco supplied Reichsführer-SS Heinrich Himmler, architect of the Nazis' Final Solution, with a list of 6,000 Jews in Spain.[137]
+
+On 14 June 1940, Spanish forces in Morocco occupied Tangier (a city under the rule of the League of Nations) and did not leave until the war's end in 1945.
+
+After the war, Franco allowed many former Nazis, such as Otto Skorzeny and Léon Degrelle, and other former fascists, to flee to Spain.
+
+According to Anti-Semitism: A Historical Encyclopedia of Prejudice and Persecution (2005):
+
+Spain provided visas for thousands of French Jews to transit Spain en route to Portugal to escape the Nazis. Spanish diplomats protected about 4,000 Jews living in Hungary, Romania, Bulgaria, Czechoslovakia, and Austria. At least some 20,000 to 30,000 Jews were allowed to pass through Spain in the first half of the War. Jews who were not allowed to enter Spain, however, were sent to the Miranda de Ebro concentration camp or deported to France. In January 1943, after the German embassy in Spain told the Spanish government that it had two months to remove its Jewish citizens from Western Europe, Spain severely limited visas, and only 800 Jews were allowed to enter the country. After the war, Franco exaggerated his contribution to helping to save Jews to end Spain's isolation, to improve Spain's image in the world.[139][140][141][142]
+
+After the war, Franco refused to recognize Israel as a legitimate state. The regime's propaganda claimed that there was an international conspiracy of Jews, Freemasons, and Communists against Spain.[143] Under the Francoist regime, Jews, along with other non-Catholic communities, were heavily discriminated against – in 1945, the regime enacted the "Spanish Bill of Rights" (Fuero de los Españoles), which allowed the worship of non-Catholic religions; however, worship of non-Catholic religions was only allowed in private, no signs to indicate they were places of worship were allowed, and only Catholic public ceremonies were allowed, making it a huge regression in comparison to the Republican Constitution of 1931, which granted Jews rights they had not enjoyed in Spain since their expulsion in 1492.[144] The situation improved with the 1967 Law on Religious Freedom, but discrimination still existed and non-Catholic groups were forced to register with the regime and to provide records of their members.[145]
+
+On 16 December 1968, the regime formally revoked the 1492 Edict of Expulsion against Spain's Jewish population.[146][147]
+
+Freedom of religion would be completely established in Spain in 1978, with the new Constitution of Spain, three years after Franco's death.
+
+Franco was recognized as the Spanish head of state by Great Britain, France and Argentina in February 1939.[148][149] Already proclaimed Generalísimo of the Nationalists and Jefe del Estado (Head of State) in October 1936,[97] he thereafter assumed the official title of "Su Excelencia el Jefe de Estado" ("His Excellency the Head of State"). He was also referred to in state and official documents as "Caudillo de España" ("the Leader of Spain"), and sometimes called "el Caudillo de la Última Cruzada y de la Hispanidad" ("the Leader of the Last Crusade and of the Hispanic heritage") and "el Caudillo de la Guerra de Liberación contra el Comunismo y sus Cómplices" ("the Leader of the War of Liberation Against Communism and Its Accomplices").
+
+On paper, Franco had more power than any Spanish leader before or since. For the first four years after taking Madrid, he ruled almost exclusively by decree. The "Law of the Head of State," passed in August 1939, "permanently confided" all governing power to Franco; he was not required to even consult the cabinet for most legislation or decrees.[150] According to Payne, Franco possessed far more day-to-day power than Hitler or Stalin possessed at the respective heights of their power. He noted that while Hitler and Stalin maintained rubber-stamp parliaments, this was not the case in Spain in the early years after the war – a situation that nominally made Franco's regime "the most purely arbitrary in the world."[151]
+
+This changed in 1942, when Franco convened a parliament known as the Cortes Españolas. It was elected in accordance with corporatist principles, and had little real power. Notably, it had no control over government spending, and the government was not responsible to it; ministers were appointed and dismissed by Franco alone.
+
+On 26 July 1947 Franco proclaimed Spain a monarchy, but did not designate a monarch. This gesture was largely done to appease the monarchists in the Movimiento Nacional (Carlists and Alfonsists). Franco left the throne vacant until 1969, proclaiming himself as a de facto regent for life. At the same time, Franco appropriated many of the privileges of a king. He wore the uniform of a Captain General (a rank traditionally reserved for the King) and resided in El Pardo Palace. In addition he began walking under a canopy, and his portrait appeared on most Spanish coins and postage stamps. He also added "by the grace of God", a phrase usually part of the styles of monarchs, to his style.
+
+Franco initially sought support from various groups. His administration marginalised fascist ideologues in favor of technocrats, many of whom were linked with Opus Dei, who promoted economic modernisation.[152]
+
+Although Franco adopted some trappings of fascism, he, and Spain under his rule, are generally not considered to be fascist; among the distinctions, fascism entails a revolutionary aim to transform society, where Franco did not seek to do so, and, to the contrary, although authoritarian, he was by nature conservative and traditional.[153][154][155][156] Stanley Payne notes that very few scholars consider him to be a "core fascist".[157] The few consistent points in Franco's long rule were above all authoritarianism, nationalism, Catholicism, anti-Freemasonry, and anti-communism.
+
+With the end of World War II, Spain suffered from the consequences of its isolation from the international economy. Spain was excluded from the Marshall Plan,[158] unlike other neutral countries in Europe. This situation ended in part when, in the light of Cold War tensions and of Spain's strategic location, the United States of America entered into a trade and military alliance with Franco. This historic alliance commenced with the visit of US President Dwight Eisenhower to Spain in 1953, which resulted in the Pact of Madrid. Spain was then admitted to the United Nations in 1955.[159] American military facilities in Spain built since then include Naval Station Rota, Morón Air Base, and Torrejón Air Base.[160]
+
+The first decade of Franco's rule following the end of the Civil War in 1939 saw continued repression and the killing of an undetermined number of political opponents. Estimation is difficult and controversial, but the total number of people who were killed during this period probably lies somewhere between 15,000 and 50,000.
+
+By the start of the 1950s Franco's state had become less violent, but during his entire rule, non-government trade unions and all political opponents across the political spectrum, from communist and anarchist organisations to liberal democrats and Catalan or Basque separatists, were either suppressed or tightly controlled with all means, up to and including violent police repression. The Confederación Nacional del Trabajo (CNT) and the Unión General de Trabajadores (UGT) trade unions were outlawed, and replaced in 1940 by the corporatist Sindicato Vertical. The Spanish Socialist Workers' Party and the Esquerra Republicana de Catalunya (ERC) were banned in 1939, while the Communist Party of Spain (PCE) went underground. The Basque Nationalist Party (PNV) went into exile, and in 1959 the ETA armed group was created to wage a low-intensity war against Franco.
+
+Franco's Spanish nationalism promoted a unitary national identity by repressing Spain's cultural diversity. Bullfighting and flamenco[161] were promoted as national traditions while those traditions not considered "Spanish" were suppressed. Franco's view of Spanish tradition was somewhat artificial and arbitrary: while some regional traditions were suppressed, flamenco, an Andalusian tradition, was considered part of a larger, national identity. All cultural activities were subject to censorship, and many, such as the Sardana, the national dance of Catalonia, were plainly forbidden (often in an erratic manner). This cultural policy was relaxed over time, most notably during the late 1960s and early 1970s.
+
+Franco also used language politics in an attempt to establish national homogeneity. He promoted the use of Castilian Spanish and suppressed other languages such as Catalan, Galician, and Basque. The legal usage of languages other than Castilian was forbidden. All government, notarial, legal and commercial documents were to be drawn up exclusively in Castilian and any documents written in other languages were deemed null and void. The usage of any other language was forbidden in schools, in advertising, and on road and shop signs. For unofficial use, citizens continued to speak these languages. This was the situation throughout the 1940s and to a lesser extent during the 1950s, but after 1960 the non-Castilian Spanish languages were freely spoken and written, and they reached bookshops and stages, although they never received official status.
+
+The Catholic Church was upheld as the established church of the Spanish State, and it regained many of the traditional privileges which it had lost under the Republic. Civil servants had to be Catholic, and some official jobs even required a "good behavior" statement by a priest. Civil marriages which had taken place in Republican Spain were declared null and void unless they had been confirmed by the Catholic Church. Divorce was forbidden, along with contraceptives, and abortion.[citation needed]
+
+Most country towns and rural areas were patrolled by pairs of Guardia Civil, a military police force for civilians, which functioned as Franco's chief means of social control. Larger cities and capitals were mostly under the jurisdiction of the Policia Armada, or the grises ("greys", due to the colour of their uniforms) as they were called.
+
+Student revolts at universities in the late 1960s and early 1970s were violently repressed by the heavily armed Policía Armada (Armed Police). Plain-clothed secret police worked inside Spanish universities.[citation needed] The enforcement by public authorities of traditional Catholic values was a stated intent of the regime, mainly by using a law (the Ley de Vagos y Maleantes, Vagrancy Act) enacted by Azaña.[162] The remaining nomads of Spain (Gitanos and Mercheros like El Lute) were especially affected. Through this law, homosexuality and prostitution were made criminal offenses in 1954.[163]
+
+Francoism professed a devotion to the traditional role of a woman in society, that is being a loving daughter and sister to her parents and brothers, being a faithful wife to her husband, and residing with her family. Official propaganda confined the role of women to family care and motherhood. Immediately after the civil war most progressive laws passed by the Republic aimed at equality between the sexes were nullified. Women could not become judges, or testify in a trial. They could not become university professors. Their affairs and economic lives had to be managed by their fathers and husbands. Until the 1970s women could not open a bank account without having it co-signed by her father or husband.[164] In the 1960s and 1970s these restrictions were somewhat relaxed.
+
+Spain attempted to retain control of its colonies throughout Franco's rule. During the Algerian War (1954–62), Madrid became the base of the Organisation armée secrète (OAS), a right-wing French Army group which sought to preserve French Algeria. Despite this, Franco was forced to make some concessions. When French Morocco became independent in 1956, he surrendered Spanish Morocco to Morocco, retaining only a few enclaves (the Plazas de soberanía). The year after, Mohammed V invaded Spanish Sahara during the Ifni War (known as the "Forgotten War" in Spain). Only in 1975, with the Green March, did Morocco take control of all of the former Spanish territories in the Sahara.
+
+In 1968, under pressure from the United Nations,[165] Spain granted Equatorial Guinea its independence, and the following year it ceded Ifni to Morocco. Under Franco, Spain also pursued a campaign to force a negotiation on the British overseas territory of Gibraltar, and closed its border with that territory in 1969. The border would not be fully reopened until 1985.
+
+The Civil War ravaged the Spanish economy.[166] Infrastructure had been damaged, workers killed, and daily business severely hampered. For more than a decade after Franco's victory, the devastated economy recovered very slowly. Franco initially pursued a policy of autarky, cutting off almost all international trade. The policy had devastating effects, and the economy stagnated. Only black marketeers could enjoy an evident affluence.
+
+On the brink of bankruptcy, a combination of pressure from the United States and the IMF managed to convince the regime to adopt a free market economy. Many of the old guard in charge of the economy were replaced by "technocrata", despite some initial opposition from Franco. From the mid-1950s there was modest acceleration in economic activity after some minor reforms and a relaxation of controls. But the growth proved too much for the economy, with shortages and inflation breaking out towards the end of the 1950s.
+
+When Franco replaced his ideological ministers with the apolitical technocrats, the regime implemented several development policies that included deep economic reforms. After a recession, growth took off from 1959, creating an economic boom that lasted until 1974, and became known as the "Spanish miracle".
+
+Concurrent with the absence of social reforms, and the economic power shift, a tide of mass emigration commenced to other European countries, and to a lesser extent, to South America. Emigration helped the regime in two ways. The country got rid of populations it would not have been able to keep in employment, and the emigrants supplied the country with much needed monetary remittances.
+
+During the 1960s, the wealthy classes of Francoist Spain experienced further increases in wealth, particularly those who remained politically faithful, while a burgeoning middle class became visible as the "economic miracle" progressed. International firms established factories in Spain where salaries were low, company taxes very low, strikes forbidden and workers' health or state protections almost unheard of. State-owned firms like the car manufacturer SEAT, truck builder Pegaso, and oil refiner INH, massively expanded production. Furthermore, Spain was virtually a new mass market. Spain became the second-fastest growing economy in the world between 1959 and 1973, just behind Japan. By the time of Franco's death in 1975, Spain still lagged behind most of Western Europe but the gap between its per capita GDP and that of the leading Western European countries had narrowed greatly, and the country had developed a large industrialised economy.
+
+Franco decided to name a monarch to succeed his regency, but the simmering tensions between the Carlists and the Alfonsoists continued. In a bid to avoid a repeat of the Carlist Wars, he offered the throne to the Habsburg Archduke Otto von Habsburg; by doing so he believed that he could eliminate the question of a Bourbon succession entirely, since the Habsburg family which had ruled the Habsburg Spain during its golden age had an alternate claim to the Spanish throne before the War of the Spanish Succession. Archduke Otto declined, stating that he would be seen as a German ruling Spain and could never forget his Austrian identity. In 1969 Franco nominated as his heir-apparent Prince Juan Carlos de Borbón, who had been educated by him in Spain, with the new title of Prince of Spain. This designation came as a surprise to the Carlist pretender to the throne, as well as to Juan Carlos's father, Don Juan, the Count of Barcelona, who had a superior claim to the throne, but whom Franco feared to be too liberal.
+
+However, when King Carlos asked Franco if he could sit in on cabinet meetings, Franco would not permit him saying that "you would do things differently." Due to the spread of democracy (excluding the Soviet Bloc) in Europe since the Second World War, Carlos could or would not have been a dictator in the way Franco had been.[167]
+
+By 1973 Franco had surrendered the function of prime minister (Presidente del Gobierno), remaining only as head of state and commander in chief of the military.
+
+As his final years progressed, tensions within the various factions of the Movimiento would consume Spanish political life, as varying groups jockeyed for position in an effort to win control of the country's future. The assassination of prime minister Luis Carrero Blanco in the 20 December 1973 bombing by ETA eventually gave an edge to the liberalizing faction.
+
+On 19 July 1974, the aged Franco fell ill from various health problems, and Juan Carlos took over as acting head of state. Franco soon recovered and on 2 September he resumed his duties as head of state. A year later he fell ill again, afflicted with further health problems, including a long battle with Parkinson's disease. Franco's last public appearance was on 1 October 1975 when, despite his gaunt and frail appearance, he gave a speech to crowds from the balcony at the Royal Palace of El Pardo in Madrid. On 30 October 1975 he fell into a coma and was put on life support. Franco's family agreed to disconnect the life-support machines. Officially, he died a few minutes after midnight on 20 November 1975 from heart failure, at the age of 82 – on the same date as the death of José Antonio Primo de Rivera, the founder of the Falange, in 1936. Historian Ricardo de la Cierva claimed that he had been told around 6 pm on 19 November that Franco had already died.[168] Juan Carlos was proclaimed King two days later.
+
+Franco's body was interred at Valle de los Caídos, a colossal memorial built by the forced labour of political prisoners to honour the casualties of both sides of the Spanish Civil War.[169][170] The site was designated by the interim government, assured by Prince Juan Carlos and Prime Minister Carlos Arias Navarro, as the burial place for Franco. According to his family, Franco did not want to be buried in the Valley, but in the Almudena Cathedral in Madrid. Nonetheless, the family agreed to the interim government's request to bury him in the Valley, and has stood by the decision. This made Franco the only person interred in the Valley who did not die during the civil war.
+
+No Western European countries sent their leaders to attend Franco's funeral due to his tenure as dictator. The following guests took part in his funeral:
+
+It was revealed that both Pinochet and Banzer revered Franco and modelled their leadership style on the Spanish leader.[171] Former US President Richard Nixon called Franco "a loyal friend and ally of the United States."[160]
+
+On 11 May 2017, the Congress of Deputies approved, by 198–1 with 140 abstentions, a motion driven by the Socialist Workers' Party ordering the Government to exhume Franco's remains.[172]
+
+On 24 August 2018, the Government of Prime Minister Pedro Sánchez approved legal amendments to the Historical Memory Law stating that only those who died during the Civil War would be buried at the Valle de los Caídos, resulting in plans to exhume Franco's remains for reburial elsewhere. Deputy Prime Minister Carmen Calvo Poyato stated that having Franco buried at the monument "shows a lack of respect ... for the victims buried there". The government gave Franco's family a 15-day deadline to decide Franco's final resting place, or else a "dignified place" will be chosen by the government.[173]
+
+On 13 September 2018, the Congress of Deputies voted 176–2, with 165 abstentions, to approve the government's plan to remove Franco's body from the monument.[174]
+
+Franco's family opposed the exhumation, and attempted to prevent it by making appeals to the Ombudsman's Office. The family expressed its wish that Franco's remains be reinterred with full military honors at the Almudena Cathedral in the centre of Madrid, the burial place he had requested before his death.[175] The demand was rejected by the Spanish Government, which issued another 15-day deadline to choose another site.[176] Because the family refused to choose another location, the Spanish Government ultimately chose to rebury Franco at the Mingorrubio Cemetery in El Pardo, where his wife Carmen Polo and a number of Francoist officials, most notably prime ministers Luis Carrero Blanco and Carlos Arias Navarro, are buried.[177] His body was to be exhumed from the Valle de los Caídos on 10 June 2019, but the Supreme Court of Spain ruled that the exhumation would be delayed until the family has exhausted all possible appeals.[178] On 24 September 2019, the Supreme Court ruled that the exhumation could proceed, and the Sánchez government announced that it would move Franco's remains to the Mingorrubio cemetery as soon as possible.[179] On 24 October 2019 his remains were moved to his wife's mausoleum which is located in the Mingorrubio Cemetery, and buried in a private ceremony.[180] Though barred by the Spanish government from being draped in the Spanish flag, Francisco Franco's grandson, also named Francisco Franco, draped his coffin in the nationalist flag.[181]
+
+According to a poll by the Spanish newspaper, El Mundo, 43% of Spanish people approved of the exhumation while 32.5% opposed it. The exhumation also seems to have been an opinion divided by party line with the Socialist party strongly in favor of its removal as well as the removal of his statue there. There seems to be no consensus on whether the statue should simply be moved or completely destroyed.[182]
+
+In Spain and abroad, the legacy of Franco remains controversial. The longevity of Franco's rule, his suppression of opposition, and the effective propaganda sustained through the years have made a detached evaluation difficult. For almost 40 years, Spaniards, and particularly children at school, were told that Divine Providence had sent Franco to save Spain from chaos, atheism, and poverty.[183] Historian Stanley Payne described Franco as being the most significant figure to dominate Spain since Philip II,[184] while Michael Seidman argued that Franco was the most successful counterrevolutionary leader of the 20th century.[185]
+
+A highly controversial figure within Spain, Franco is seen as a divisive leader. Supporters credit him for keeping Spain neutral and uninvaded in World War II. They emphasize his strong anti-communist and nationalist views, economic policies, and opposition to socialism as major factors in Spain's post-war economic success and later international integration.[186] Abroad he had support from Winston Churchill and many American Catholics, but was strongly opposed by the Roosevelt and Truman administrations.[187][188]
+
+Conversely, critics on the left have denounced him as a tyrant responsible for thousands of deaths in years-long political repression, and have called him complicit in atrocities committed by Axis forces during World War II due to his support of Axis governments.
+
+When he died in 1975, the major parties of the left and the right agreed to follow the "Pact of Forgetting." To secure the transition to democracy, they agreed not to have investigations or prosecutions dealing with the civil war or Franco. The agreement effectively lapsed after 2000, the year the Association for the Recovery of Historical Memory was founded and the public debate started.[189] In 2006, a poll indicated that almost two-thirds of Spaniards favored a "fresh investigation into the war."[190]
+
+The Oxford Living Dictionary uses Franco's regime as an example of fascism.[191] However, most historians agree that although Franco and Spain under his rule adopted some trappings of fascism they are generally not considered to be fascist,[153][154][155][156][192] at most describing the early totalitarian phase of his rule as a "fascistized dictatorship",[193] or "semi-fascist regime".[194]
+
+Franco served as a role model for several anti-communist dictators in South America. Augusto Pinochet is known to have admired Franco.[195] Similarly, as recently as 2006, Franco supporters in Spain have honored Pinochet.[196]
+
+In 2006, the BBC reported that Maciej Giertych, an MEP of the clerical-nationalist League of Polish Families, had expressed admiration for Franco, stating that the Spanish leader "guaranteed the maintenance of traditional values in Europe".[197]
+
+Spaniards who suffered under Franco's rule have sought to remove memorials of his regime. Most government buildings and streets that were named after Franco during his rule have been reverted to their original names. Owing to Franco's human-rights record, the Spanish government in 2007 banned all official public references to the Franco regime and began the removal of all statues, street names and memorials associated with the regime, with the last statue reportedly being removed in 2008 in the city of Santander.[198] Churches that retain plaques commemorating Franco and the victims of his Republican opponents may lose state aid.[199] Since 1978, the national anthem of Spain, the Marcha Real, does not include lyrics introduced by Franco. Attempts to give the national anthem new lyrics have failed due to lack of consensus.
+
+In March 2006, the Permanent Commission of the Parliamentary Assembly of the Council of Europe unanimously adopted a resolution "firmly" condemning the "multiple and serious violations" of human rights committed in Spain under the Francoist regime from 1939 to 1975.[200][201] The resolution was at the initiative of Leo Brincat and of the historian Luis María de Puig, and was the first international official condemnation of the repression enacted by Franco's regime.[200] The resolution also urged that historians (professional and amateur) be given access to the various archives of the Francoist regime, including those of the private Francisco Franco National Foundation (FNFF) which, along with other Francoist archives, remain inaccessible to the public as of 2006.[200] The FNFF received various archives from the El Pardo Palace, and is alleged to have sold some of them to private individuals.[202] Furthermore, the resolution urged the Spanish authorities to set up an underground exhibit in the Valle de los Caidos monument to explain the "terrible" conditions in which it was built.[200] Finally, it proposed the construction of monuments to commemorate Franco's victims in Madrid and other important cities.[200]
+
+In Spain, a commission to "repair the dignity" and "restore the memory" of the "victims of Francoism" (Comisión para reparar la dignidad y restituir la memoria de las víctimas del franquismo) was approved in 2004, and is directed by the socialist deputy Prime Minister María Teresa Fernández de la Vega.[200]
+
+Recently the Association for the Recovery of Historical Memory (ARHM) initiated a systematic search for mass graves of people executed during Franco's regime, which has been supported since the Spanish Socialist Workers' Party's (PSOE) victory during the 2004 elections by José Luis Rodríguez Zapatero's government. A Ley de la memoria histórica de España (Law on the Historical Memory of Spain) was approved on 28 July 2006, by the Council of Ministers,[203] but it took until 31 October 2007, for the Congress of Deputies to approve an amended version as "The Bill to recognise and extend rights and to establish measures in favour of those who suffered persecution or violence during the Civil War and the Dictatorship" (in common parlance still known as Law of Historical Memory).[204] The Senate approved the bill on 10 December 2007.[205]
+
+Official endeavors to preserve the historical memory of the Franco regime include exhibitions like the one the Museu d'Història de Catalunya (Museum of Catalan History) organised around the prison experience.[206]
+
+The accumulated wealth of Franco's family (including much real estate inherited from Franco, such as the Pazo de Meirás, the Canto del Pico in Torrelodones and the Casa Cornide [es] in A Coruña[202]), and its provenance, have also become matters of public discussion. Estimates of the family's wealth have ranged from 350 million to 600 million euros.[202] While Franco was dying, the Francoist Cortes voted a large public pension for his wife Carmen Polo, which the later democratic governments kept paying. At the time of her death in 1988, Carmen Polo was receiving as a pension more than 12.5 million pesetas (four million more than the salary of Felipe González, then head of the government).[202]

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+Francisco Franco Bahamonde (/ˈfræŋkoʊ/, Spanish: [fɾanˈθisko ˈfɾaŋko]; 4 December 1892 – 20 November 1975) was a Spanish general who led the Nationalist forces in overthrowing the Second Spanish Republic during the Spanish Civil War and thereafter ruled over Spain from 1939 to 1975 as a dictator, assuming the title Caudillo. This period in Spanish history, from the Nationalist victory to Franco's death, is commonly known as Francoist Spain or the Francoist dictatorship.
+
+Born in Ferrol, Spain into an upper-class military family, Franco served in the Spanish Army as a cadet in the Toledo Infantry Academy from 1907 to 1910. While serving in Morocco, he rose through the ranks to become brigadier general in 1926, aged 33, becoming the youngest general in Spain. Two years later Franco became the director of the General Military Academy in Zaragoza. As a conservative and monarchist, Franco regretted the abolition of the monarchy and the establishment of the Second Republic in 1931. He was devastated by the closing of his Academy, but nevertheless continued his service in the Republican Army.[1] His career redoubled after the right-wing CEDA and PRR won the 1933 election empowering him to lead the suppression of the 1934 uprising in Asturias. Franco was briefly elevated to Chief of Army Staff before the 1936 election moved the leftist Popular Front into power, relegating him to the Canary Islands. Two years later Franco, after initial reluctance, joined a military coup which, after failing to take Spain, sparked the Spanish Civil War.
+
+During the war, he commandeered Spain's colonial army in Africa and after the death of much of the rebel leadership became his faction's only leader, later appointed Generalissimo and Head of State in 1936. He consolidated all nationalist parties into the FET y de las JONS (creating a one-party state). Three years later the Nationalists declared victory which extended Franco's dictatorship over Spain through a period of repression of political opponents. His dictatorship's use of forced labor, concentration camps, and executions led to between 30,000 and 50,000 deaths.[9][10] Combined with wartime killings, this brings the death toll of the White Terror to between 100,000 and 200,000.[11][12] In post-war Spain, Franco ruled with more power than any Spanish leader before or since and developed a cult of personality around his rule by founding the Movimiento Nacional.  During World War II he maintained Spanish neutrality but supported the Axis — whose members Italy and Germany had supported him during the Civil War — in various ways, damaging the country's international reputation.
+
+During the start of the Cold War, Franco lifted Spain out of its mid-19th century economic depression through technocratic and economically liberal policies, presiding over a period of rampant growth known as the "Spanish miracle". At the same time, his regime transitioned from being totalitarian to authoritarian with limited pluralism and became a leader in the anti-Communist movement, garnering support from the West, particularly the United States.[13][14] The dictatorship softened and Luis Carrero Blanco became Franco's éminence grise, whose role expanded after Franco struggled with Parkinson's disease in the 1960s. In 1973 Franco resigned as prime minister – separated from the head of state office since 1966 – due to advanced age and illness, but remained in power as the latter and commander-in-chief. Franco died in 1975, aged 82, and was entombed in the Valle de los Caídos. He restored the monarchy in his final years, being succeeded by Juan Carlos as King of Spain, who, in turn, led the Spanish transition to democracy.
+
+The legacy of Franco in Spanish history remains controversial as the nature of his dictatorship changed over time. His reign was marked by both brutal repression, with thousands killed, and economic prosperity, which greatly improved the quality of life in Spain. His dictatorial style proved highly adaptable, which enabled wide-sweeping social and economic reform, while consistent pursuits during his reign centered on highly centralised government, authoritarianism, nationalism, national Catholicism, anti-freemasonry, and anti-communism.
+
+Francisco Franco Bahamonde was born on 4 December 1892 in the Calle Frutos Saavedra in El Ferrol, Galicia.[15] He was baptised thirteen days later at the military church of San Francisco, with the baptismal name Francisco Paulino Hermenegildo Teódulo;[15] Francisco for his paternal grandfather, Paulino for his godfather, Hermenegildo for his maternal grandmother and godmother, and Teódulo for the saint day of his birth. Franco was born into a seafaring family of Andalusian ancestry.[16][b]
+
+After relocating to Galicia, the family was involved in the Spanish Navy, and over the span of two centuries produced naval officers for six uninterrupted generations (including several admirals),[19] down to Franco's father Nicolás Franco y Salgado Araújo (22 November 1855 – 22 February 1942).[20]
+
+His mother, María del Pilar Bahamonde y Pardo de Andrade (15 October 1865 – 28 February 1934), was from an upper-middle-class Roman Catholic family. Her father, Ladislao Bahamonde Ortega, was the commissar of naval equipment at the Port of El Ferrol. Franco's parents married in 1890 in the Church of San Francisco in El Ferrol.[21] The young Franco spent much of his childhood with his two brothers, Nicolás and Ramón, and his two sisters, María del Pilar and María de la Paz. His brother Nicolás was naval officer and diplomat who  married María Isabel Pascual del Pobil y Ravello.[22] Ramón was an internationally-known aviator, a Freemason originally with leftist political leanings.[23] He was also the second sibling to die, killed in an air accident on a military mission in 1938.[23]
+
+Franco's father was a naval officer who reached the rank of vice admiral (intendente general). When Franco was fourteen, his father moved away to Madrid following a reassignment and ultimately abandoned his family, marrying another woman. While Franco did not suffer any great abuse at his father's hand, he would never overcome his antipathy for his father and largely ignored him for the rest of his life; years after becoming dictator, Franco wrote a brief novel Raza under the pseudonym Jaime de Andrade, whose protagonist is believed by Stanley Payne to represent the idealised man Franco wished his father had been. Conversely, Franco strongly identified with his mother (who always wore widow's black once she realised her husband had abandoned her) and learned from her moderation, austerity, self-control, family solidarity and respect for Catholicism, though he would also inherit his father's harshness, coldness and implacability.[24]
+
+Francisco was to follow his father into the Navy, but as a result of the Spanish–American War the country lost much of its navy as well as most of its colonies. Not needing any more officers, the Naval Academy admitted no new entrants from 1906 to 1913. To his father's chagrin, Francisco decided to try the Spanish Army. In 1907, he entered the Infantry Academy in Toledo. At the age of fourteen, Franco was one of the youngest members of his class, with most boys being between sixteen and eighteen. He was short and was bullied for his small size. His grades were average; though his good memory meant he seldom struggled in mental tests, his small stature was a hindrance in physical tests. He would graduate in July 1910 as second lieutenant, coming in at position 251 out of 312, though this may have been less to do with his grades than his small size, young age and reduced physical presence; Stanley Payne observes that by the time Civil War began, Franco had already become a major general and would soon be a generalissimo, while none of his higher-ranking fellow cadets had managed to get beyond the rank of lieutenant-colonel.[25][26] At 19, Franco was promoted to the rank of first lieutenant in June 1912.[27][28] Two years later, he obtained a commission to Morocco. Spanish efforts to occupy their new African protectorate provoked the Second Melillan campaign in 1909 with native Moroccans, the first of a period of Riffian rebellions. Their tactics resulted in heavy losses among Spanish military officers, and also provided an opportunity to earn promotion through merit. It was said that officers would receive either la caja o la faja (a coffin or a general's sash). Franco quickly gained a reputation as a good officer.
+
+In 1913, Franco transferred into the newly formed regulares: Moroccan colonial troops with Spanish officers, who acted as shock troops. This transfer into a perilous role may have been decided because Franco failed to win the hand of his first love, Sofía Subirán. The letters between the two were found and she was questioned by journalists.
+
+In 1916, aged 23 as a captain, he was shot by enemy machine gun fire. He was badly wounded in the abdomen, specifically the liver, in a skirmish at El Biutz. The physicians of the battle later concluded that his intestines were spared because he inhaled the moment he was shot. In 2008, it was alleged by historian José María Zavala that this injury had left Franco with only one testicle. Zavala cites Ana Puigvert, whose father Antonio Puigvert, was Franco's physician.[29]
+
+His recovery was seen by native troops in Africa as a spiritual event – they believed Franco to be blessed with baraka, or protected by God. He was recommended for promotion to major and to receive Spain's highest honour for gallantry, the coveted Cruz Laureada de San Fernando. Both proposals were denied citing the 23-year-old Franco's young age as the reason for denial. Instead Franco received the Cross of Maria Cristina, First Class.[30]
+
+With that he was promoted to major at the end of February 1917 at age 24. This made him the youngest major in the Spanish army. From 1917 to 1920, he served in Spain. In 1920, Lieutenant Colonel José Millán Astray, a histrionic but charismatic officer, founded the Spanish Foreign Legion, on similar lines as the French Foreign Legion. Franco became the Legion's second-in-command and returned to Africa. In the Rif War, on 24 July 1921, the poorly commanded and overextended Spanish Army suffered a crushing defeat at Annual from the Republic of the Rif led by the Abd el-Krim brothers. The Legion and supporting units relieved the Spanish enclave of Melilla after a three-day forced march led by Franco. In 1923, by now a lieutenant colonel, he was made commander of the Legion.
+
+On 22 October 1923, Franco married María del Carmen Polo y Martínez-Valdès (11 June 1900 – 6 February 1988).[31] Three years later, on 14 September 1926, the couple had a daughter, María del Carmen. Franco would have a close relationship with his daughter and was a proud parent, though his traditionalist attitudes and increasing responsibilities meant he left much of the child-rearing to his wife.[32][33] Following his honeymoon Franco was summoned to Madrid to be presented to King Alfonso XIII.[34] This and other occasions of royal attention would mark him during the Republic as a monarchical officer. Promoted to colonel, Franco led the first wave of troops ashore at Al Hoceima (Spanish: Alhucemas) in 1925. This landing in the heartland of Abd el-Krim's tribe, combined with the French invasion from the south, spelled the beginning of the end for the short-lived Republic of the Rif. Franco's recognition eventually caught up with him, and he was promoted to brigadier general on 3 February 1926. This made him the youngest general in Spain, and perhaps, along with Major-General Joe Sweeney of the Irish Army, one of the youngest generals in Europe.[35] In 1928 Franco was appointed director of the newly created General Military Academy of Zaragoza, a new college for all army cadets, replacing the former separate institutions for young men seeking to become officers in infantry, cavalry, artillery, and other branches of the army. Franco was removed as Director of the Zaragoza Military Academy in 1931; about 95% of his former Zaragoza cadets later came to side with him in the Civil War.
+
+The municipal elections of 12 April 1931 were largely seen as plebiscite on the monarchy. The Republican-Socialist alliance failed to win the majority of the municipality cities in Spain, but had a landslide victory in all large cities and in almost all provincial capitals.[36] The monarchists and the army deserted Alfonso XIII and the King decided to leave the country into exile, giving way to the Second Spanish Republic. Although Franco believed that the majority of the Spanish people still supported the crown, and although he regretted the end of the monarchy, he did not object, nor did he challenge the legitimacy of the republic.[37] But the closing of the Academy in June by the provisional War Minister Manuel Azaña was a major setback for Franco and provoked his first clash with the Spanish Republic. Azaña found Franco's farewell speech to the cadets insulting.[38] In his speech Franco stressed the Republic's need for discipline and respect.[39] Azaña entered an official reprimand into Franco's personnel file and for six months Franco was without a post and under surveillance.[38]
+
+In December 1931, a new reformist, liberal, and democratic constitution was declared. It included strong provisions enforcing a broad secularisation of the Catholic country, which included the abolishing of Catholic schools and charities, which many moderate committed Catholics opposed.[40] At this point once the constituent assembly had fullfilled its mandate of approving a new constitution, it should have[clarification needed] arranged for regular parliamentary elections and adjourned. Fearing the increasing popular opposition, the Radical and Socialist majority postponed the regular elections, therefore prolonging their way in power for two more years. This way the republican government of Manuel Azaña initiated numerous reforms to what in their view would "modernize" the country.[41]
+
+Franco was a subscriber to the journal of Acción Española, a monarchist organisation, and a firm believer in a supposed Jewish-Masonic-Bolshevik conspiracy, or contubernio (filthy cohabitation).  The conspiracy suggested that Jews, Freemasons, Communists, and other leftists alike sought the destruction of Christian Europe, with Spain the principal target.[42]
+
+On 5 February 1932, Franco was given a command in A Coruña. Franco avoided involvement in José Sanjurjo's attempted coup that year, and even wrote a hostile letter to Sanjurjo expressing his anger over the attempt. As a result of Azaña's military reform, in January 1933 Franco was relegated from first to 24th in the list of brigadiers. The same year, on 17 February he was given the military command of the Balearic Islands. The post was above his rank, but Franco was still angered that he was purposely stuck in positions he disliked. It was quite common for conservative officers to be moved or demoted.
+
+In 1932 the Jesuits who were in charge of the best schools throughout the country were banned and had all their property confiscated. The army was further reduced. Landowners were expropriated. Home rule was granted to Catalonia, with a local parliament and a president of its own. [41] In June 1933 Pope Pius XI issued the encyclical Dilectissima Nobis, "On Oppression of the Church of Spain", raising his voice against the persecution of the Catholic Church in Spain.[43]
+
+The elections held in October 1933 resulted in a centre-right majority. The political party with the most votes was the Confederación Español de Derechas Autónomas ("CEDA"), but president Alcalá-Zamora declined to invite the leader of the CEDA, Gil Robles, to form a government. Instead he invited the Radical Republican Party's Alejandro Lerroux to do so. Despite receiving the most votes, CEDA was denied cabinet positions for nearly a year.[44] After a year of intense pressure, CEDA, the largest party in the congress, was finally successful in forcing the acceptance of three ministries. The entrance of CEDA in the government, despite being normal in a parliamentary democracy, was not well accepted by the left.  The Socialists triggered an insurrection that they had been preparing for nine months.[45] A general strike was called by the UGT and the PSOE in the name of the Alianza Obrera. The issue was that the Left Republicans identified the Republic not with democracy or constitutional law but a specific set of left-wing policies and politicians. Any deviation, even if democratic, was seen as treasonous.[46] A Catalan state was proclaimed by Catalan nationalist leader Lluis Companys, but it lasted just ten hours. Despite an attempt at a general stoppage in Madrid, other strikes did not endure. This left Asturian strikers to fight alone.[47]
+
+In several mining towns in Asturias, local unions gathered small arms and were determined to see the strike through. It began on the evening of 4 October, with the miners occupying several towns, attacking and seizing local Civil and Assault Guard barracks.[48] Thirty four priests, six young seminarists with ages between 18 and 21, and several businessmen and civil guards were summarily executed by the revolutionaries in Mieres and Sama, 58 religious buildings including churches, convents and part of the university at Oviedo were burned and destroyed.[49][50] Franco, already General of Division and aide to the war minister, Diego Hidalgo, was put in command of the operations directed to suppress the violent insurgency. Troops of the Spanish Army of Africa carried this out, with General Eduardo López Ochoa as commander in the field. After two weeks of heavy fighting (and a death toll estimated between 1,200 and 2,000), the rebellion was suppressed.
+
+The insurgency in Asturias sparked a new era of violent anti-Christian persecutions, initiated the practice of atrocities against the clergy,[50] and sharpened the antagonism between Left and Right. Franco and López Ochoa (who, prior to the campaign in Asturias, had been seen as a left-leaning officer)[51] emerged as officers prepared to use "troops against Spanish civilians as if they were a foreign enemy".[52] Franco described the rebellion to a journalist in Oviedo as, "a frontier war and its fronts are socialism, communism and whatever attacks civilisation to replace it with barbarism." Though the colonial units sent to the north by the government at Franco's recommendation[53] consisted of the Spanish Foreign Legion and the Moroccan Regulares Indigenas, the right-wing press portrayed the Asturian rebels as lackeys of a foreign Jewish-Bolshevik conspiracy.[54]
+
+With this rebellion against established political legitimate authority, the Socialists showed identical repudiation of representative institutional system that anarchists had practiced.[55] The Spanish historian Salvador de Madariaga, an Azaña supporter, and an exhiled vocal opponent of Francisco Franco is the author of a sharp critical reflection against the participation of the left in the revolt: “The uprising of 1934 is unforgivable. The argument that Mr Gil Robles tried to destroy the Constitution to establish fascism was, at once, hypocritical and false. With the rebellion of 1934, the Spanish left lost even the shadow of moral authority to condemn the rebellion of 1936.” [56]
+
+At the start of the Civil War, López Ochoa was assassinated. Some time after these events, Franco was briefly commander-in-chief of the Army of Africa (from 15 February onwards), and from 19 May 1935, on, Chief of the General Staff.
+
+In the end of 1935 President Alcalá-Zamora manipulated a petty-corruption issue into a major scandal in parliament, and eliminated Alejandro Lerroux, the head of the Radical Republican Party, from premiership. Subsequently, Alcalá-Zamora vetoed the logical replacement, a majority center-right coalition, led by the CEDA, which would reflect the composition of the parliament. He then arbitrarily appointed an interim prime minister and after a short period announced the dissolution of parliament and new elections.[57]
+
+Two wide coalitions formed: the Popular Front on the left, ranging from Republican Union to Communists, and the Frente Nacional on the right, ranging from the centre radicals to the conservative Carlists. On 16 February 1936 the elections ended in a virtual draw, but in the evening leftist mobs started to interfere in the balloting and in the registration of votes distorting the results.[58][59] Stanley G. Payne claims that the process was a major electoral fraud, with widespread violation of the laws and the constitution.[60] In line with Payne's point of view, in 2017 two Spanish scholars, Manuel Álvarez Tardío and Roberto Villa García published the result of a major research work where they concluded that the 1936 elections were rigged.[61][62]
+
+On 19 February the cabinet presided by Portela Valladares resigned, with a new cabinet being quickly set up, composed chiefly of members of the Republican Left and the Republican Union and presided by Manuel Azaña.[63]
+
+José Calvo Sotelo, who acquired anti-communism as the axis of his parliamentary speeches, became the speaker of violent propaganda—advocating for a military coup d'état; formulating a catastrophist discourse of a dichotomous choice between "communism" or a markedly totalitarian "National" State, setting the mood of the masses for a military rebellion.[64] The diffusion of the myth about an alleged Communist coup d'état as well a pretended state of "social chaos" became pretexts for a coup.[64] Franco himself along with General Emilio Mola had stirred an Anti-Communist campaign in Morocco.[64]
+
+At the same time PSOE's left-wing socialists became more radical. Julio Álvarez del Vayo talked about "Spain's being converted into a socialist Republic in association with the Soviet Union". Francisco Largo Caballero declared that "the organized proletariat will carry everything before it and destroy everything until we reach our goal".[65] The country rapidly descended into anarchy. Even the staunch socialist Indalecio Prieto, at a party rally in Cuenca in May 1936, complained: "we have never seen so tragic a panorama or so great a collapse as in Spain at this moment. Abroad Spain is classified as insolvent. This is not the road to socialism or communism but to desperate anarchism without even the advantage of liberty".[65]
+
+On 23 February Franco was sent to the Canary Islands to serve as the islands' military commander, an appointment perceived by him as a destierro (banishment).[66] Meanwhile, a conspiracy led by General Mola was taking shape.
+
+Interested in the parliamentary immunity granted by a seat at the Cortes, Franco intended to stand as candidate of the Right Bloc alongside José Antonio Primo de Rivera for the by-election in the province of Cuenca programmed for 3 May 1936, after the results of the February 1936 election were annulled in the constituency. But Primo de Rivera refused to run alongside a military officer (and Franco in particular) and Franco himself ultimately desisted on 26 April, one day before the decision of the election authority.[67] By that time, PSOE politician Indalecio Prieto already deemed Franco as "possible caudillo for a military uprising".[67]
+
+The disenchantment with Azaña's rulling continued to grow and was dramatically voiced by Miguel de Unamuno, a republican and one of Spain's most respected intellectuals, who in June 1936 told a reporter who published his statement in El Adelanto that President Manuel Azaña should "commit suicide as a patriotic act".[68]
+
+In June 1936, Franco was contacted and a secret meeting was held within La Esperanza forest on Tenerife to discuss starting a military coup.[69] An obelisk commemorating this historic meeting was erected at the site in a clearing at Las Raíces.[70]
+
+Outwardly, Franco maintained an ambiguous attitude until nearly July. On 23 June 1936, he wrote to the head of the government, Casares Quiroga, offering to quell the discontent in the Spanish Republican Army, but received no reply. The other rebels were determined to go ahead con Paquito o sin Paquito (with Paquito or without Paquito; Paquito being a diminutive of Paco, which in turn is short for Francisco), as it was put by José Sanjurjo, the honorary leader of the military uprising. After various postponements, 18 July was fixed as the date of the uprising. The situation reached a point of no return and, as presented to Franco by Mola, the coup was unavoidable and he had to choose a side. He decided to join the rebels and was given the task of commanding the Army of Africa. A privately owned DH 89 De Havilland Dragon Rapide, flown by two British pilots, Cecil Bebb and Hugh Pollard,[71] was chartered in England on 11 July to take Franco to Africa.
+
+The coup underway was precipitated by the assassination of the right-wing opposition leader Calvo Sotelo in retaliation for the murder of assault guard José Castillo, which had been committed by a group headed by a civil guard and composed of assault guards and members of the socialist militias.[72] On 17 July, one day earlier than planned, the Army of Africa rebelled, detaining their commanders. On 18 July, Franco published a manifesto[73] and left for Africa, where he arrived the next day to take command.
+
+A week later the rebels, who soon called themselves the Nationalists, controlled a third of Spain; most naval units remained under control of the Republican loyalist forces, which left Franco isolated. The coup had failed in the attempt to bring a swift victory, but the Spanish Civil War had begun. The revolt was remarkably devoid of any particular ideology.[74] The major goal was to put an end to anarchical disorder.[75] Franco himself certainly detested communism, but had no commitment to any ideology: his stand was motivated not by foreign fascism but by Spanish tradition and patriotism.[75]
+
+The Spanish Civil War began in July 1936 and officially ended with Franco's victory in April 1939, leaving 190,000[76] to 500,000[77] dead. Despite the Non-Intervention Agreement of August 1936, the war was marked by foreign intervention on behalf of both sides, leading to international repercussions. The nationalist side was supported by Fascist Italy, which sent the Corpo Truppe Volontarie, and later by Nazi Germany, which assisted with the Condor Legion. They were opposed by the Soviet Union and communists, socialists, and anarchists within Spain. The United Kingdom and France strictly adhered to the arms embargo,[citation needed] provoking dissensions within the French Popular Front coalition which was led by Léon Blum, but the Republican side was nonetheless supported by the Soviet Union and volunteers who fought in the International Brigades (see for example Ken Loach's Land and Freedom).
+
+Some historians, such as Ernst Nolte, have considered that Adolf Hitler and Joseph Stalin used the Spanish Civil war as a testing ground for modern warfare,[citation needed] being quickly set up and that the Spanish Civil War, along with World War II, to be part of a European Civil War which lasted from 1936 to 1945 and was mainly characterised as a left/right ideological conflict. This interpretation has not been accepted by most historians,[who?] who consider the Spanish Civil War and the Second World War to be two distinct conflicts. Among other things, they point to the political heterogeneity on both sides (See Spanish Civil War: other factions) and criticise a monolithic interpretation, which overlooks the local nuances of Spanish history.
+
+Following 18 July 1936 pronunciamiento, Franco assumed the leadership of the 30,000 soldiers of the Spanish Army of Africa. The first days of the insurgency were marked by a serious need to secure control over the Spanish Moroccan Protectorate. On one side, Franco had to win the support of the natives and their (nominal) authorities, and, on the other, had to ensure his control over the army. His method was the summary execution of some 200 senior officers loyal to the Republic (one of them his own cousin). His loyal bodyguard was shot by Manuel Blanco.[78] Franco's first problem was how to move his troops to the Iberian Peninsula, since most units of the Navy had remained in control of the Republic and were blocking the Strait of Gibraltar. He requested help from Benito Mussolini, who responded with an unconditional offer of arms and planes; in Germany Wilhelm Canaris, the head of the Abwehr military intelligence, persuaded Hitler to support the Nationalists. From 20 July onward Franco was able, with a small group of 22 mainly German Junkers Ju 52 aircraft, to initiate an air bridge to Seville, where his troops helped to ensure the rebel control of the city. Through representatives, he started to negotiate with the United Kingdom, Germany, and Italy for more military support, and above all for more aircraft. Negotiations were successful with the last two on 25 July and aircraft began to arrive in Tetouan on 2 August. On 5 August Franco was able to break the blockade with the newly arrived air support, successfully deploying a ship convoy with some 2,000 soldiers.
+
+On the Republican side, in July 26, just eight days after the revolt had started, an international communist conference was held at Prague to arrange plans to help the Republican Government. It decide to raise an international brigade of 5,000 men and a fund of 1 billion francs to be administered by a commission where Largo Caballero and Dolores Ibárruri had prominent roles.[79] At the same time communist parties throughout the world quicly launched a full scale propaganda campaign in support of the Popular Front. The Communist International immediately reinforced its activity, sending to Spain its leader Georgi Dimitrov, and Palmiro Togliatti the chief of the Communist Party of Italy.[80][81] From August onward, aid from the Soviet Union began; over one ship per day arrived at Spain's Mediterranean ports carrying munitions, rifles, machine guns, hand grenades, artillery, trucks. With the cargo came Soviet agents, technicians, instructors and propagandists.[80]
+
+The Communist International immediately started to organize the International Brigades with great care to conceal or minimize the communist character of the enterprise and to make it appear as a campaign on behalf of progressive democracy.[80] Attractive misleading names were deliberately chosen, such as "Garibaldi" in Italy or "Abraham Lincoln" in the United States.[80]
+
+In early August, the situation in western Andalusia was stable enough to allow Franco to organise a column (some 15,000 men at its height), under the command of then Lieutenant-Colonel Juan Yagüe, which would march through Extremadura towards Madrid. On 11 August Mérida was taken, and on 15 August Badajoz, thus joining both nationalist-controlled areas. Additionally, Mussolini ordered a voluntary army, the Corpo Truppe Volontarie (CTV) of fully motorised units (some 12,000 Italians), to Seville, and Hitler added to them a professional squadron from the Luftwaffe (2JG/88) with about 24 planes. All these planes had the Nationalist Spanish insignia painted on them, but were flown by Italian and German nationals. The backbone of Franco's aviation in those days was the Italian SM.79 and SM.81 bombers, the biplane Fiat CR.32 fighter and the German Junkers Ju 52 cargo-bomber and the Heinkel He 51 biplane fighter.
+
+On 21 September, with the head of the column at the town of Maqueda (some 80 km away from Madrid), Franco ordered a detour to free the besieged garrison at the Alcázar of Toledo, which was achieved on 27 September. This controversial decision gave the Popular Front time to strengthen its defenses in Madrid and hold the city that year, but with Soviet support.[82] Kennan alleges that, once Stalin had decided to assist the Spanish Republicans, the operation was put in place with remarkable speed and energy. The first load of arms and tanks arrived as early as 26 September and was secretly unloaded at night. Advisers accompanied the armaments. Soviet officers were in effective charge of military operations on the Madrid front. Kennan believes that this operation was originally conducted in good faith with no other purpose than saving the Republic.[83] Effort was made to encourage the Spanish Communist Party to seize power,[84] but the holding of Alcázar was an important morale and propaganda success for the Nationalists, because it is clear that Hitler's primary aim was not a Franco victory but to prolong the war by the active intervention of the Soviet Government as well as that of Italy, Britain, and France in the Civil War.[85]
+
+Hitler's policy for Spain was shrewd and pragmatic. His instructions were clear: "A hundred per cent Franco's victory was not desirable from a German Point of view; rather were we interested in a continuance of the war and in the keeping up of the tension in the Mediterranean."[86] Hitler wanted to help Franco just enough to gain his gratitude and to prevent the side supported by the Soviet Union from winning, but not large enough to give the Caudillo a quick victory.[87]
+
+By February 1937 the Soviet Union's military help started to taper off, to be replaced by limited economic aid. A more likely motive was Stalin's instinct for self-preservation;  the Spanish Civil War had aroused a spirit of heroism in support of freedom more in line with Trotskyism, and such ideas might be exported to the Soviet Union. Further proof of this is that Modin stated that Stalin decided to attack the extreme Left, particularly Trotskyites and militants of the POUM before liquidating Franco.[88] Those who had served in Spain were tainted in Stalin's view and were singled out for harshness in the purges and were virtually all eliminated. The defector Orlov, who worked for the NKVD in Spain, confirms that he was told by a Soviet general, whom Orlov did not want to name, that when the general returned to Moscow to seek further instructions, he was told that the Politburo had adopted a new line towards Spain. Until then, the policy of the Politburo was to assist Republican Spain by supplying armaments, Soviet pilots, and tanks to bring about a speedy victory over Franco, but now the Politburo had revised its strategy. Stalin had come to the conclusion that "it would be more advantageous to the Soviet Union if neither of the warring camps gained proponderant strength, and if the war in Spain dragged on as long as possible and thus tied up Hitler for a long time." The general who informed Orlov of this was shocked by the Machiavellian calculation of the Politburo which, in its desire to obtain time, wanted the Spanish people to bleed as long as possible.[89]
+
+The designated leader of the uprising, General José Sanjurjo, died on 20 July 1936, in a plane crash. In the nationalist zone, "political life ceased."[90] Initially, only military command mattered: this was divided into regional commands (Emilio Mola in the North, Gonzalo Queipo de Llano in Seville commanding Andalusia, Franco with an independent command, and Miguel Cabanellas in Zaragoza commanding Aragon). The Spanish Army of Morocco was itself split into two columns, one commanded by General Juan Yagüe and the other commanded by Colonel José Varela.
+
+From 24 July a coordinating junta was established, based at Burgos. Nominally led by Cabanellas, as the most senior general,[91] it initially included Mola, three other generals, and two colonels; Franco was later added in early August.[92] On 21 September it was decided that Franco was to be commander-in-chief (this unified command was opposed only by Cabanellas),[93] and, after some discussion, with no more than a lukewarm agreement from Queipo de Llano and from Mola, also head of government.[94] He was, doubtlessly, helped to this primacy by the fact that, in late July, Hitler had decided that all of Germany's aid to the nationalists would go to Franco.[95]
+
+Mola had been somewhat discredited as the main planner of the attempted coup that had now degenerated into a civil war, and was strongly identified with the Carlist monarchists and not at all with the Falange, a party with Fascist leanings and connections ("phalanx", a far-right Spanish political party founded by José Antonio Primo de Rivera), nor did he have good relations with Germany. Queipo de Llano and Cabanellas had both previously rebelled against the dictatorship of General Miguel Primo de Rivera and were therefore discredited in some nationalist circles, and Falangist leader José Antonio Primo de Rivera was in prison in Alicante (he would be executed a few months later). The desire to keep a place open for him prevented any other Falangist leader from emerging as a possible head of state. Franco's previous aloofness from politics meant that he had few active enemies in any of the factions that needed to be placated, and he had also cooperated in recent months with both Germany and Italy.[96]
+
+On 1 October 1936, in Burgos, Franco was publicly proclaimed as Generalísimo of the National army and Jefe del Estado (Head of State).[97] When Mola was killed in another air accident a year later on 2 June 1937 (which some believe was an assassination), no military leader was left from those who organized the conspiracy against the Republic between 1933 and 1935.[98]
+
+Franco personally guided military operations from this time until the end of the war. Franco himself was not a strategic genius but he was very effective at organisation, administration, logistics and diplomacy.[99] After the failed assault on Madrid in November 1936, Franco settled on a piecemeal approach to winning the war, rather than bold maneuvering. As with his decision to relieve the garrison at Toledo, this approach has been subject of some debate: some of his decisions, such as in June 1938 when he preferred to head for Valencia instead of Catalonia, remain particularly controversial from a military viewpoint. Valencia, Castellon and Alicante saw the last Republican troops defeated by Franco.
+
+Although both Germany and Italy provided military support to Franco, the degree of influence of both powers on his direction of the war seems to have been very limited. Nevertheless, the Italian troops, despite not always being effective, were present in most of the large operations in large numbers, while the German aircraft helped the Nationalist air force dominate the skies for most of the war.
+
+Franco's direction of the German and Italian forces was limited, particularly in the direction of the Condor Legion, but he was by default their supreme commander, and they rarely made decisions on their own. For reasons of prestige it was decided to continue assisting Franco until the end of the war, and Italian and German troops paraded on the day of the final victory in Madrid.[100]
+
+The Nationalist victory could be accounted for by various factors:[101]
+
+The Nazis were disappointed with Franco's resistance to installing fascism. Historian James S. Corum states:
+
+Robert H. Whealey provides more detail:
+
+From 1937 to 1948 the Franco regime was a hybrid as Franco fused the ideologically incompatible national-syndicalist Falange ("Phalanx", a fascist Spanish political party founded by José Antonio Primo de Rivera) and the Carlist monarchist parties into one party under his rule, dubbed Falange Española Tradicionalista y de las Juntas de Ofensiva Nacional-Sindicalista (FET y de las JONS), which became the only legal party in 1939. Unlike some other fascist movements, the Falangists had developed an official program in 1934, the "Twenty-Seven Points".[106] In 1937, Franco assumed as the tentative doctrine of his regime 26 out of the original 27 points.[107] Franco made himself jefe nacional (National Chief) of the new FET (Falange Española Tradicionalista; Traditionalist Spanish Phalanx) with a secretary, Junta Political and National Council to be named subsequently by himself. Five days later (24 April) the raised-arm salute of the Falange was made the official salute of the Nationalist regime.[108] In 1939 the personalist style heavily predominated, with ritualistic invocations of "Franco, Franco, Franco."[109] The Falangists' hymn, Cara al Sol, became the semi-national anthem of Franco's not-yet-established regime.
+
+This new political formation appeased the pro-German Falangists while tempering them with the anti-German Carlists. Franco's brother-in-law Ramón Serrano Súñer, who was his main political advisor, was able to turn the various parties under Franco against each other to absorb a series of political confrontations against Franco himself. Franco expelled the original leading members of both the Carlists (Manuel Fal Condé) and the Falangists (Manuel Hedilla) to secure his political future. Franco also appeased the Carlists by exploiting the Republicans' anti-clericalism in his propaganda, in particular concerning the "Martyrs of the war". While the Republican forces presented the war as a struggle to defend the Republic against fascism, Franco depicted himself as the defender of "Catholic Spain" against "atheist communism".
+
+By early 1939 only Madrid (see History of Madrid) and a few other areas remained under control of the government forces. On 27 February Chamberlain's Britain and Daladier's France officially recognised the Franco regime. On 28 March 1939, with the help of pro-Franco forces inside the city (the "fifth column" General Mola had mentioned in propaganda broadcasts in 1936), Madrid fell to the Nationalists. The next day, Valencia, which had held out under the guns of the Nationalists for close to two years, also surrendered. Victory was proclaimed on 1 April 1939, when the last of the Republican forces surrendered. On the same day, Franco placed his sword upon the altar of a church and in a vow, promised that he would never again take up his sword unless Spain itself was threatened with invasion.
+
+Although Germany had recognised the Franco Government, Franco's policy towards Germany was extremely cautious until spectacular German victories at the beginning of the Second World War. An early indication that Franco was going to keep his distance from Germany soon proved true.[85] A rumoured state visit by Franco to Germany did not take place and a further rumour of a visit by Goering to Spain, after he had enjoyed a cruise in the Western Mediterranean, again did not materialise. Instead Goering had to return to Berlin.[110] This proved how right Eden was when he said "Whatever the final outcome of the strife ... the Spanish people will continue to display that proud independence, that arrogant individualism which is a characteristic of the race. There are twenty-four million reasons why Spain will never for long be dominated by the forces or controlled by the advice of any foreign power."[111]
+
+During the Civil War and in the aftermath, a period known as the White Terror took place. This saw mass executions of Republican and other Nationalist enemies, standing in contrast to the war-time Red Terror. Historical analysis and investigations estimate the number of executions by the Franco regime during this time to be between 100,000 and 200,000 dead.
+
+Stanley G. Payne approximates 50,000 executions by the Republicans and at least 70,000 executions by the Nationalists during the civil war,[77][2][112] with the victory being followed by a further 30,000 executions by the Nationalists.[2] Recent searches conducted with parallel excavations of mass graves in Spain (in particular by the Association for the Recovery of Historical Memory, ARMH) estimate the total of people executed after the civil war between 15,000 and 35,000.[3]
+
+Julián Casanova Ruiz, nominated in 2008 among the experts in the first judicial investigation (conducted by judge Baltasar Garzón) against the Francoist crimes,[113] as well as historians Josep Fontana and Hugh Thomas, estimate the deaths in the White Terror to be around 150,000 in total.[4][114][5][6] According to Paul Preston, 150,000 wartime civilian executions took place in the Francoist area, as well as 50,000 in the Republican area, in addition to 20,000 civilians executed by the Franco regime after the end of the war.[115][c] According to Helen Graham, the Spanish working classes became to the Francoist project what the Jews were to the German Volksgemeinschaft.[117]
+
+According to Gabriel Jackson and Antony Beevor, the number of victims of the "White Terror" (executions and hunger or illness in prisons) only between 1939 and 1943 was 200,000.[100] Beevor "reckons Franco's ensuing 'white terror' claimed 200,000 lives. The 'red terror' had already killed 38,000."[118] Julius Ruiz concludes that "although the figures remain disputed, a minimum of 37,843 executions were carried out in the Republican zone with a maximum of 150,000 executions (including 50,000 after the war) in Nationalist Spain."[119]
+
+Despite the end of the war, guerrilla resistance to Franco, known as "the Maquis", occurred in the Pyrenees, carrying out sabotage and robberies against the Francoist regime. Several exiled Republicans also fought in the French resistance against the German occupation in Vichy France during World War II. In 1944, a group of republican veterans from the French resistance invaded the Val d'Aran in northwest Catalonia, but were quickly defeated. The activities of the Maquis continued well into the 1950s.
+
+The end of the war led to hundreds of thousands of exiles, mostly to France, but also to Mexico, Chile, Cuba, and the United States.[120] On the other side of the Pyrenees, refugees were confined in internment camps in France, such as Camp Gurs or Camp Vernet, where 12,000 Republicans were housed in squalid conditions (mostly soldiers from the Durruti Division[121]). The 17,000 refugees housed in Gurs were divided into four categories: Brigadists, pilots, Gudaris and ordinary "Spaniards". The Gudaris (Basques) and the pilots easily found local backers and jobs, and were allowed to quit the camp, but the farmers and ordinary people, who could not find relations in France, were encouraged by the French government, in agreement with the Francoist government, to return to Spain. The great majority did so and were turned over to the Francoist authorities in Irún. From there they were transferred to the Miranda de Ebro camp for "purification" according to the Law of Political Responsibilities.
+
+After the proclamation by Marshal Philippe Pétain of the Vichy France regime, the refugees became political prisoners, and the French police attempted to round up those who had been liberated from the camp. Along with other "undesirables", they were sent to the Drancy internment camp before being deported to Nazi Germany. 5,000 Spaniards thus died in Mauthausen concentration camp.[122] The Chilean poet Pablo Neruda, who had been named by the Chilean President Pedro Aguirre Cerda special consul for immigration in Paris, was given responsibility for what he called "the noblest mission I have ever undertaken": shipping more than 2,000 Spanish refugees, who had been housed by the French in squalid camps, to Chile on an old cargo ship, the Winnipeg.[123]
+
+In September 1939 World War II began. On 23 October 1940, Hitler and Franco met in Hendaye in France to discuss the possibility of Spain's entry on the side of the Axis. Franco's demands, including supplies of food and fuel, as well as Spanish control of Gibraltar and French North Africa, proved too much for Hitler. At the time Hitler did not want to risk damaging his relations with the new Vichy French government. (An oft-cited remark attributed to Hitler is that the German leader said that he would rather have some of his own teeth extracted than to have to personally deal further with Franco.)[124][125] Franco had received important support from Adolf Hitler and Benito Mussolini during the Spanish Civil War, and he had signed the Anti-Comintern Pact. He described Spain as part of the Axis in official documents[citation needed], while offering various kinds of support to Italy and Germany. He allowed Spanish soldiers to volunteer to fight in the German Army against the Soviet Union (the Blue Division), but forbade Spaniards to fight in the West against the democracies. Franco's common ground with Hitler was particularly weakened by Hitler's propagation of Nazi mysticism and his attempts to manipulate Christianity, which went against Franco's fervent commitment to defending Catholicism.[126] Contributing to the disagreement was an ongoing dispute over German mining rights in Spain. Some historians argue that Franco made demands he knew Hitler would not accede to, in order to stay out of the war. Other historians argue that Franco, as the leader of a destroyed and bankrupt country in chaos following a brutal three-year civil war, simply had little to offer the Axis and that the Spanish armed forces were not ready for a major war. It has also been suggested that Franco decided not to join the war after the resources he requested from Hitler in October 1940 were not forthcoming.[127]
+
+According to some scholars, after the Fall of France in June 1940, Spain did adopt a pro-Axis stance (for example, German and Italian ships and U-boats were allowed to use Spanish naval facilities) before returning to a more neutral position in late 1943 when the tide of the war had turned decisively against the Axis Powers, and Italy had changed sides. Franco was initially keen to join the war before the UK was defeated.[128]
+
+In the winter of 1940–41 Franco toyed with the idea of a "Latin Bloc" formed by Spain, Portugal, Vichy France, the Vatican and Italy, without much consequence.[129] Franco had cautiously decided to enter the war on the Axis side in June 1940, and to prepare his people for war, an anti-British and anti-French campaign was launched in the Spanish media that demanded French Morocco, Cameroon and Gibraltar.[130] On 19 June 1940, Franco pressed along a message to Hitler saying he wanted to enter the war, but Hitler was annoyed at Franco's demand for the French colony of Cameroon, which had been German before World War I, and which Hitler was planning on taking back for Plan Z.[131] Franco seriously considered blocking allied access to the Mediterranean Sea by invading British-held Gibraltar,[124] but he abandoned the idea after learning that the plan would have likely failed due to Gibraltar being too heavily defended. In addition, declaring war on the UK and its allies would no doubt give them an  opportunity to capture both the Canary Islands and Spanish Morocco, as well as possibly launch an invasion of mainland Spain itself.[124][132] Franco was aware that his air force would be defeated if going into action against the Royal Air Force, and the Royal Navy would be able to blockade Spain to prevent imports of crucial materials such as oil. Spain depended on oil imports from the United States, which were almost certain to be cut off if Spain formally joined the Axis. Franco and Serrano Suñer held a meeting with Mussolini and Ciano in Bordighera, Italy on 12 February 1941.[133] Mussolini affected not to be interested in Franco's help due to the defeats his forces had suffered in North Africa and the Balkans, and he even told Franco that he wished he could find any way to leave the war. When the invasion of the Soviet Union began on 22 June 1941, Franco's foreign minister Ramón Serrano Suñer immediately suggested the formation of a unit of military volunteers to join the invasion.[citation needed] Volunteer Spanish troops (the División Azul, or "Blue Division") fought on the Eastern Front under German command from 1941 to 1944. Some historians have argued that not all of the Blue Division were true volunteers and that Franco expended relatively small but significant resources to aid the Axis powers' battle against the Soviet Union.
+
+Franco was initially disliked by Cuban President Fulgencio Batista, who, during World War II, suggested a joint U.S.-Latin American declaration of war on Spain to overthrow Franco's regime.[134] Hitler may not have really wanted Spain to join the war, as he needed neutral harbors to import materials from countries in Latin America and elsewhere. In addition Hitler felt Spain would be a burden as it would be dependent on Germany for help. By 1941 Vichy French forces were proving their effectiveness in North Africa, reducing the need for Spanish help, and Hitler was wary about opening up a new front on the western coast of Europe as he struggled to reinforce the Italians in Greece and Yugoslavia. Franco signed a revised Anti-Comintern Pact on 25 November 1941. Spain continued to import[clarification needed] war materials and trade wolfram with Germany until August 1944 when the Germans withdrew from the Spanish frontier.[127]
+
+Spanish neutrality during World War II was appreciated and publicly acknowledged by leading Allied statesmen.[135] In November 1942 President Roosevelt wrote to General Franco: "...your nation and mine are friends in the best sense of the word."[136] In May 1944 Winston Churchill stated in the House of Commons: "in the dark days of the war the attitude of the Spanish Government in not giving our enemies passage through Spain was extremelly helpful to us...I must say that I shall always consider that a service was rendered...by Spain, not only to the United Kingdom  and to the British Empire and Commonwealth, but to the cause of the United Nations."[136] Similar gratitude was also expressed by the Provisional French Government.[136] Franco interposed no obstacle to Britain's construction of a big air base extending out of Gibraltar into Spanish territorial waters, and welcomed the Anglo-American landings in North Africa. Moreover, Spain did not intern any of the 1,200 American airmen who were forced to land in the country, but gave them shelter and helped them to leave.[136]
+
+After the war, the Spanish government tried to destroy all evidence of its cooperation with the Axis. In 2010 documents were discovered showing that on 13 May 1941, Franco ordered his provincial governors to compile a list of Jews while he negotiated an alliance with the Axis powers.[137] Franco supplied Reichsführer-SS Heinrich Himmler, architect of the Nazis' Final Solution, with a list of 6,000 Jews in Spain.[137]
+
+On 14 June 1940, Spanish forces in Morocco occupied Tangier (a city under the rule of the League of Nations) and did not leave until the war's end in 1945.
+
+After the war, Franco allowed many former Nazis, such as Otto Skorzeny and Léon Degrelle, and other former fascists, to flee to Spain.
+
+According to Anti-Semitism: A Historical Encyclopedia of Prejudice and Persecution (2005):
+
+Spain provided visas for thousands of French Jews to transit Spain en route to Portugal to escape the Nazis. Spanish diplomats protected about 4,000 Jews living in Hungary, Romania, Bulgaria, Czechoslovakia, and Austria. At least some 20,000 to 30,000 Jews were allowed to pass through Spain in the first half of the War. Jews who were not allowed to enter Spain, however, were sent to the Miranda de Ebro concentration camp or deported to France. In January 1943, after the German embassy in Spain told the Spanish government that it had two months to remove its Jewish citizens from Western Europe, Spain severely limited visas, and only 800 Jews were allowed to enter the country. After the war, Franco exaggerated his contribution to helping to save Jews to end Spain's isolation, to improve Spain's image in the world.[139][140][141][142]
+
+After the war, Franco refused to recognize Israel as a legitimate state. The regime's propaganda claimed that there was an international conspiracy of Jews, Freemasons, and Communists against Spain.[143] Under the Francoist regime, Jews, along with other non-Catholic communities, were heavily discriminated against – in 1945, the regime enacted the "Spanish Bill of Rights" (Fuero de los Españoles), which allowed the worship of non-Catholic religions; however, worship of non-Catholic religions was only allowed in private, no signs to indicate they were places of worship were allowed, and only Catholic public ceremonies were allowed, making it a huge regression in comparison to the Republican Constitution of 1931, which granted Jews rights they had not enjoyed in Spain since their expulsion in 1492.[144] The situation improved with the 1967 Law on Religious Freedom, but discrimination still existed and non-Catholic groups were forced to register with the regime and to provide records of their members.[145]
+
+On 16 December 1968, the regime formally revoked the 1492 Edict of Expulsion against Spain's Jewish population.[146][147]
+
+Freedom of religion would be completely established in Spain in 1978, with the new Constitution of Spain, three years after Franco's death.
+
+Franco was recognized as the Spanish head of state by Great Britain, France and Argentina in February 1939.[148][149] Already proclaimed Generalísimo of the Nationalists and Jefe del Estado (Head of State) in October 1936,[97] he thereafter assumed the official title of "Su Excelencia el Jefe de Estado" ("His Excellency the Head of State"). He was also referred to in state and official documents as "Caudillo de España" ("the Leader of Spain"), and sometimes called "el Caudillo de la Última Cruzada y de la Hispanidad" ("the Leader of the Last Crusade and of the Hispanic heritage") and "el Caudillo de la Guerra de Liberación contra el Comunismo y sus Cómplices" ("the Leader of the War of Liberation Against Communism and Its Accomplices").
+
+On paper, Franco had more power than any Spanish leader before or since. For the first four years after taking Madrid, he ruled almost exclusively by decree. The "Law of the Head of State," passed in August 1939, "permanently confided" all governing power to Franco; he was not required to even consult the cabinet for most legislation or decrees.[150] According to Payne, Franco possessed far more day-to-day power than Hitler or Stalin possessed at the respective heights of their power. He noted that while Hitler and Stalin maintained rubber-stamp parliaments, this was not the case in Spain in the early years after the war – a situation that nominally made Franco's regime "the most purely arbitrary in the world."[151]
+
+This changed in 1942, when Franco convened a parliament known as the Cortes Españolas. It was elected in accordance with corporatist principles, and had little real power. Notably, it had no control over government spending, and the government was not responsible to it; ministers were appointed and dismissed by Franco alone.
+
+On 26 July 1947 Franco proclaimed Spain a monarchy, but did not designate a monarch. This gesture was largely done to appease the monarchists in the Movimiento Nacional (Carlists and Alfonsists). Franco left the throne vacant until 1969, proclaiming himself as a de facto regent for life. At the same time, Franco appropriated many of the privileges of a king. He wore the uniform of a Captain General (a rank traditionally reserved for the King) and resided in El Pardo Palace. In addition he began walking under a canopy, and his portrait appeared on most Spanish coins and postage stamps. He also added "by the grace of God", a phrase usually part of the styles of monarchs, to his style.
+
+Franco initially sought support from various groups. His administration marginalised fascist ideologues in favor of technocrats, many of whom were linked with Opus Dei, who promoted economic modernisation.[152]
+
+Although Franco adopted some trappings of fascism, he, and Spain under his rule, are generally not considered to be fascist; among the distinctions, fascism entails a revolutionary aim to transform society, where Franco did not seek to do so, and, to the contrary, although authoritarian, he was by nature conservative and traditional.[153][154][155][156] Stanley Payne notes that very few scholars consider him to be a "core fascist".[157] The few consistent points in Franco's long rule were above all authoritarianism, nationalism, Catholicism, anti-Freemasonry, and anti-communism.
+
+With the end of World War II, Spain suffered from the consequences of its isolation from the international economy. Spain was excluded from the Marshall Plan,[158] unlike other neutral countries in Europe. This situation ended in part when, in the light of Cold War tensions and of Spain's strategic location, the United States of America entered into a trade and military alliance with Franco. This historic alliance commenced with the visit of US President Dwight Eisenhower to Spain in 1953, which resulted in the Pact of Madrid. Spain was then admitted to the United Nations in 1955.[159] American military facilities in Spain built since then include Naval Station Rota, Morón Air Base, and Torrejón Air Base.[160]
+
+The first decade of Franco's rule following the end of the Civil War in 1939 saw continued repression and the killing of an undetermined number of political opponents. Estimation is difficult and controversial, but the total number of people who were killed during this period probably lies somewhere between 15,000 and 50,000.
+
+By the start of the 1950s Franco's state had become less violent, but during his entire rule, non-government trade unions and all political opponents across the political spectrum, from communist and anarchist organisations to liberal democrats and Catalan or Basque separatists, were either suppressed or tightly controlled with all means, up to and including violent police repression. The Confederación Nacional del Trabajo (CNT) and the Unión General de Trabajadores (UGT) trade unions were outlawed, and replaced in 1940 by the corporatist Sindicato Vertical. The Spanish Socialist Workers' Party and the Esquerra Republicana de Catalunya (ERC) were banned in 1939, while the Communist Party of Spain (PCE) went underground. The Basque Nationalist Party (PNV) went into exile, and in 1959 the ETA armed group was created to wage a low-intensity war against Franco.
+
+Franco's Spanish nationalism promoted a unitary national identity by repressing Spain's cultural diversity. Bullfighting and flamenco[161] were promoted as national traditions while those traditions not considered "Spanish" were suppressed. Franco's view of Spanish tradition was somewhat artificial and arbitrary: while some regional traditions were suppressed, flamenco, an Andalusian tradition, was considered part of a larger, national identity. All cultural activities were subject to censorship, and many, such as the Sardana, the national dance of Catalonia, were plainly forbidden (often in an erratic manner). This cultural policy was relaxed over time, most notably during the late 1960s and early 1970s.
+
+Franco also used language politics in an attempt to establish national homogeneity. He promoted the use of Castilian Spanish and suppressed other languages such as Catalan, Galician, and Basque. The legal usage of languages other than Castilian was forbidden. All government, notarial, legal and commercial documents were to be drawn up exclusively in Castilian and any documents written in other languages were deemed null and void. The usage of any other language was forbidden in schools, in advertising, and on road and shop signs. For unofficial use, citizens continued to speak these languages. This was the situation throughout the 1940s and to a lesser extent during the 1950s, but after 1960 the non-Castilian Spanish languages were freely spoken and written, and they reached bookshops and stages, although they never received official status.
+
+The Catholic Church was upheld as the established church of the Spanish State, and it regained many of the traditional privileges which it had lost under the Republic. Civil servants had to be Catholic, and some official jobs even required a "good behavior" statement by a priest. Civil marriages which had taken place in Republican Spain were declared null and void unless they had been confirmed by the Catholic Church. Divorce was forbidden, along with contraceptives, and abortion.[citation needed]
+
+Most country towns and rural areas were patrolled by pairs of Guardia Civil, a military police force for civilians, which functioned as Franco's chief means of social control. Larger cities and capitals were mostly under the jurisdiction of the Policia Armada, or the grises ("greys", due to the colour of their uniforms) as they were called.
+
+Student revolts at universities in the late 1960s and early 1970s were violently repressed by the heavily armed Policía Armada (Armed Police). Plain-clothed secret police worked inside Spanish universities.[citation needed] The enforcement by public authorities of traditional Catholic values was a stated intent of the regime, mainly by using a law (the Ley de Vagos y Maleantes, Vagrancy Act) enacted by Azaña.[162] The remaining nomads of Spain (Gitanos and Mercheros like El Lute) were especially affected. Through this law, homosexuality and prostitution were made criminal offenses in 1954.[163]
+
+Francoism professed a devotion to the traditional role of a woman in society, that is being a loving daughter and sister to her parents and brothers, being a faithful wife to her husband, and residing with her family. Official propaganda confined the role of women to family care and motherhood. Immediately after the civil war most progressive laws passed by the Republic aimed at equality between the sexes were nullified. Women could not become judges, or testify in a trial. They could not become university professors. Their affairs and economic lives had to be managed by their fathers and husbands. Until the 1970s women could not open a bank account without having it co-signed by her father or husband.[164] In the 1960s and 1970s these restrictions were somewhat relaxed.
+
+Spain attempted to retain control of its colonies throughout Franco's rule. During the Algerian War (1954–62), Madrid became the base of the Organisation armée secrète (OAS), a right-wing French Army group which sought to preserve French Algeria. Despite this, Franco was forced to make some concessions. When French Morocco became independent in 1956, he surrendered Spanish Morocco to Morocco, retaining only a few enclaves (the Plazas de soberanía). The year after, Mohammed V invaded Spanish Sahara during the Ifni War (known as the "Forgotten War" in Spain). Only in 1975, with the Green March, did Morocco take control of all of the former Spanish territories in the Sahara.
+
+In 1968, under pressure from the United Nations,[165] Spain granted Equatorial Guinea its independence, and the following year it ceded Ifni to Morocco. Under Franco, Spain also pursued a campaign to force a negotiation on the British overseas territory of Gibraltar, and closed its border with that territory in 1969. The border would not be fully reopened until 1985.
+
+The Civil War ravaged the Spanish economy.[166] Infrastructure had been damaged, workers killed, and daily business severely hampered. For more than a decade after Franco's victory, the devastated economy recovered very slowly. Franco initially pursued a policy of autarky, cutting off almost all international trade. The policy had devastating effects, and the economy stagnated. Only black marketeers could enjoy an evident affluence.
+
+On the brink of bankruptcy, a combination of pressure from the United States and the IMF managed to convince the regime to adopt a free market economy. Many of the old guard in charge of the economy were replaced by "technocrata", despite some initial opposition from Franco. From the mid-1950s there was modest acceleration in economic activity after some minor reforms and a relaxation of controls. But the growth proved too much for the economy, with shortages and inflation breaking out towards the end of the 1950s.
+
+When Franco replaced his ideological ministers with the apolitical technocrats, the regime implemented several development policies that included deep economic reforms. After a recession, growth took off from 1959, creating an economic boom that lasted until 1974, and became known as the "Spanish miracle".
+
+Concurrent with the absence of social reforms, and the economic power shift, a tide of mass emigration commenced to other European countries, and to a lesser extent, to South America. Emigration helped the regime in two ways. The country got rid of populations it would not have been able to keep in employment, and the emigrants supplied the country with much needed monetary remittances.
+
+During the 1960s, the wealthy classes of Francoist Spain experienced further increases in wealth, particularly those who remained politically faithful, while a burgeoning middle class became visible as the "economic miracle" progressed. International firms established factories in Spain where salaries were low, company taxes very low, strikes forbidden and workers' health or state protections almost unheard of. State-owned firms like the car manufacturer SEAT, truck builder Pegaso, and oil refiner INH, massively expanded production. Furthermore, Spain was virtually a new mass market. Spain became the second-fastest growing economy in the world between 1959 and 1973, just behind Japan. By the time of Franco's death in 1975, Spain still lagged behind most of Western Europe but the gap between its per capita GDP and that of the leading Western European countries had narrowed greatly, and the country had developed a large industrialised economy.
+
+Franco decided to name a monarch to succeed his regency, but the simmering tensions between the Carlists and the Alfonsoists continued. In a bid to avoid a repeat of the Carlist Wars, he offered the throne to the Habsburg Archduke Otto von Habsburg; by doing so he believed that he could eliminate the question of a Bourbon succession entirely, since the Habsburg family which had ruled the Habsburg Spain during its golden age had an alternate claim to the Spanish throne before the War of the Spanish Succession. Archduke Otto declined, stating that he would be seen as a German ruling Spain and could never forget his Austrian identity. In 1969 Franco nominated as his heir-apparent Prince Juan Carlos de Borbón, who had been educated by him in Spain, with the new title of Prince of Spain. This designation came as a surprise to the Carlist pretender to the throne, as well as to Juan Carlos's father, Don Juan, the Count of Barcelona, who had a superior claim to the throne, but whom Franco feared to be too liberal.
+
+However, when King Carlos asked Franco if he could sit in on cabinet meetings, Franco would not permit him saying that "you would do things differently." Due to the spread of democracy (excluding the Soviet Bloc) in Europe since the Second World War, Carlos could or would not have been a dictator in the way Franco had been.[167]
+
+By 1973 Franco had surrendered the function of prime minister (Presidente del Gobierno), remaining only as head of state and commander in chief of the military.
+
+As his final years progressed, tensions within the various factions of the Movimiento would consume Spanish political life, as varying groups jockeyed for position in an effort to win control of the country's future. The assassination of prime minister Luis Carrero Blanco in the 20 December 1973 bombing by ETA eventually gave an edge to the liberalizing faction.
+
+On 19 July 1974, the aged Franco fell ill from various health problems, and Juan Carlos took over as acting head of state. Franco soon recovered and on 2 September he resumed his duties as head of state. A year later he fell ill again, afflicted with further health problems, including a long battle with Parkinson's disease. Franco's last public appearance was on 1 October 1975 when, despite his gaunt and frail appearance, he gave a speech to crowds from the balcony at the Royal Palace of El Pardo in Madrid. On 30 October 1975 he fell into a coma and was put on life support. Franco's family agreed to disconnect the life-support machines. Officially, he died a few minutes after midnight on 20 November 1975 from heart failure, at the age of 82 – on the same date as the death of José Antonio Primo de Rivera, the founder of the Falange, in 1936. Historian Ricardo de la Cierva claimed that he had been told around 6 pm on 19 November that Franco had already died.[168] Juan Carlos was proclaimed King two days later.
+
+Franco's body was interred at Valle de los Caídos, a colossal memorial built by the forced labour of political prisoners to honour the casualties of both sides of the Spanish Civil War.[169][170] The site was designated by the interim government, assured by Prince Juan Carlos and Prime Minister Carlos Arias Navarro, as the burial place for Franco. According to his family, Franco did not want to be buried in the Valley, but in the Almudena Cathedral in Madrid. Nonetheless, the family agreed to the interim government's request to bury him in the Valley, and has stood by the decision. This made Franco the only person interred in the Valley who did not die during the civil war.
+
+No Western European countries sent their leaders to attend Franco's funeral due to his tenure as dictator. The following guests took part in his funeral:
+
+It was revealed that both Pinochet and Banzer revered Franco and modelled their leadership style on the Spanish leader.[171] Former US President Richard Nixon called Franco "a loyal friend and ally of the United States."[160]
+
+On 11 May 2017, the Congress of Deputies approved, by 198–1 with 140 abstentions, a motion driven by the Socialist Workers' Party ordering the Government to exhume Franco's remains.[172]
+
+On 24 August 2018, the Government of Prime Minister Pedro Sánchez approved legal amendments to the Historical Memory Law stating that only those who died during the Civil War would be buried at the Valle de los Caídos, resulting in plans to exhume Franco's remains for reburial elsewhere. Deputy Prime Minister Carmen Calvo Poyato stated that having Franco buried at the monument "shows a lack of respect ... for the victims buried there". The government gave Franco's family a 15-day deadline to decide Franco's final resting place, or else a "dignified place" will be chosen by the government.[173]
+
+On 13 September 2018, the Congress of Deputies voted 176–2, with 165 abstentions, to approve the government's plan to remove Franco's body from the monument.[174]
+
+Franco's family opposed the exhumation, and attempted to prevent it by making appeals to the Ombudsman's Office. The family expressed its wish that Franco's remains be reinterred with full military honors at the Almudena Cathedral in the centre of Madrid, the burial place he had requested before his death.[175] The demand was rejected by the Spanish Government, which issued another 15-day deadline to choose another site.[176] Because the family refused to choose another location, the Spanish Government ultimately chose to rebury Franco at the Mingorrubio Cemetery in El Pardo, where his wife Carmen Polo and a number of Francoist officials, most notably prime ministers Luis Carrero Blanco and Carlos Arias Navarro, are buried.[177] His body was to be exhumed from the Valle de los Caídos on 10 June 2019, but the Supreme Court of Spain ruled that the exhumation would be delayed until the family has exhausted all possible appeals.[178] On 24 September 2019, the Supreme Court ruled that the exhumation could proceed, and the Sánchez government announced that it would move Franco's remains to the Mingorrubio cemetery as soon as possible.[179] On 24 October 2019 his remains were moved to his wife's mausoleum which is located in the Mingorrubio Cemetery, and buried in a private ceremony.[180] Though barred by the Spanish government from being draped in the Spanish flag, Francisco Franco's grandson, also named Francisco Franco, draped his coffin in the nationalist flag.[181]
+
+According to a poll by the Spanish newspaper, El Mundo, 43% of Spanish people approved of the exhumation while 32.5% opposed it. The exhumation also seems to have been an opinion divided by party line with the Socialist party strongly in favor of its removal as well as the removal of his statue there. There seems to be no consensus on whether the statue should simply be moved or completely destroyed.[182]
+
+In Spain and abroad, the legacy of Franco remains controversial. The longevity of Franco's rule, his suppression of opposition, and the effective propaganda sustained through the years have made a detached evaluation difficult. For almost 40 years, Spaniards, and particularly children at school, were told that Divine Providence had sent Franco to save Spain from chaos, atheism, and poverty.[183] Historian Stanley Payne described Franco as being the most significant figure to dominate Spain since Philip II,[184] while Michael Seidman argued that Franco was the most successful counterrevolutionary leader of the 20th century.[185]
+
+A highly controversial figure within Spain, Franco is seen as a divisive leader. Supporters credit him for keeping Spain neutral and uninvaded in World War II. They emphasize his strong anti-communist and nationalist views, economic policies, and opposition to socialism as major factors in Spain's post-war economic success and later international integration.[186] Abroad he had support from Winston Churchill and many American Catholics, but was strongly opposed by the Roosevelt and Truman administrations.[187][188]
+
+Conversely, critics on the left have denounced him as a tyrant responsible for thousands of deaths in years-long political repression, and have called him complicit in atrocities committed by Axis forces during World War II due to his support of Axis governments.
+
+When he died in 1975, the major parties of the left and the right agreed to follow the "Pact of Forgetting." To secure the transition to democracy, they agreed not to have investigations or prosecutions dealing with the civil war or Franco. The agreement effectively lapsed after 2000, the year the Association for the Recovery of Historical Memory was founded and the public debate started.[189] In 2006, a poll indicated that almost two-thirds of Spaniards favored a "fresh investigation into the war."[190]
+
+The Oxford Living Dictionary uses Franco's regime as an example of fascism.[191] However, most historians agree that although Franco and Spain under his rule adopted some trappings of fascism they are generally not considered to be fascist,[153][154][155][156][192] at most describing the early totalitarian phase of his rule as a "fascistized dictatorship",[193] or "semi-fascist regime".[194]
+
+Franco served as a role model for several anti-communist dictators in South America. Augusto Pinochet is known to have admired Franco.[195] Similarly, as recently as 2006, Franco supporters in Spain have honored Pinochet.[196]
+
+In 2006, the BBC reported that Maciej Giertych, an MEP of the clerical-nationalist League of Polish Families, had expressed admiration for Franco, stating that the Spanish leader "guaranteed the maintenance of traditional values in Europe".[197]
+
+Spaniards who suffered under Franco's rule have sought to remove memorials of his regime. Most government buildings and streets that were named after Franco during his rule have been reverted to their original names. Owing to Franco's human-rights record, the Spanish government in 2007 banned all official public references to the Franco regime and began the removal of all statues, street names and memorials associated with the regime, with the last statue reportedly being removed in 2008 in the city of Santander.[198] Churches that retain plaques commemorating Franco and the victims of his Republican opponents may lose state aid.[199] Since 1978, the national anthem of Spain, the Marcha Real, does not include lyrics introduced by Franco. Attempts to give the national anthem new lyrics have failed due to lack of consensus.
+
+In March 2006, the Permanent Commission of the Parliamentary Assembly of the Council of Europe unanimously adopted a resolution "firmly" condemning the "multiple and serious violations" of human rights committed in Spain under the Francoist regime from 1939 to 1975.[200][201] The resolution was at the initiative of Leo Brincat and of the historian Luis María de Puig, and was the first international official condemnation of the repression enacted by Franco's regime.[200] The resolution also urged that historians (professional and amateur) be given access to the various archives of the Francoist regime, including those of the private Francisco Franco National Foundation (FNFF) which, along with other Francoist archives, remain inaccessible to the public as of 2006.[200] The FNFF received various archives from the El Pardo Palace, and is alleged to have sold some of them to private individuals.[202] Furthermore, the resolution urged the Spanish authorities to set up an underground exhibit in the Valle de los Caidos monument to explain the "terrible" conditions in which it was built.[200] Finally, it proposed the construction of monuments to commemorate Franco's victims in Madrid and other important cities.[200]
+
+In Spain, a commission to "repair the dignity" and "restore the memory" of the "victims of Francoism" (Comisión para reparar la dignidad y restituir la memoria de las víctimas del franquismo) was approved in 2004, and is directed by the socialist deputy Prime Minister María Teresa Fernández de la Vega.[200]
+
+Recently the Association for the Recovery of Historical Memory (ARHM) initiated a systematic search for mass graves of people executed during Franco's regime, which has been supported since the Spanish Socialist Workers' Party's (PSOE) victory during the 2004 elections by José Luis Rodríguez Zapatero's government. A Ley de la memoria histórica de España (Law on the Historical Memory of Spain) was approved on 28 July 2006, by the Council of Ministers,[203] but it took until 31 October 2007, for the Congress of Deputies to approve an amended version as "The Bill to recognise and extend rights and to establish measures in favour of those who suffered persecution or violence during the Civil War and the Dictatorship" (in common parlance still known as Law of Historical Memory).[204] The Senate approved the bill on 10 December 2007.[205]
+
+Official endeavors to preserve the historical memory of the Franco regime include exhibitions like the one the Museu d'Història de Catalunya (Museum of Catalan History) organised around the prison experience.[206]
+
+The accumulated wealth of Franco's family (including much real estate inherited from Franco, such as the Pazo de Meirás, the Canto del Pico in Torrelodones and the Casa Cornide [es] in A Coruña[202]), and its provenance, have also become matters of public discussion. Estimates of the family's wealth have ranged from 350 million to 600 million euros.[202] While Franco was dying, the Francoist Cortes voted a large public pension for his wife Carmen Polo, which the later democratic governments kept paying. At the time of her death in 1988, Carmen Polo was receiving as a pension more than 12.5 million pesetas (four million more than the salary of Felipe González, then head of the government).[202]

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+Francis I (French: François Ier; Middle French: Francoys; 12 September 1494 – 31 March 1547) was King of France from 1515 until his death in 1547. He was the son of Charles, Count of Angoulême, and Louise of Savoy. He succeeded his first cousin once removed and father-in-law Louis XII, who died without a son.
+
+A prodigious patron of the arts, he initiated the French Renaissance by attracting many Italian artists to work for him, including Leonardo da Vinci, who brought the Mona Lisa with him, which Francis had acquired. Francis' reign saw important cultural changes with the rise of absolute monarchy in France, the spread of humanism and Protestantism, and the beginning of French exploration of the New World. Jacques Cartier and others claimed lands in the Americas for France and paved the way for the expansion of the first French colonial empire.
+
+For his role in the development and promotion of a standardized French language, he became known as le Père et Restaurateur des Lettres (the 'Father and Restorer of Letters').[1] He was also known as François du Grand Nez ('Francis of the Large Nose'), the Grand Colas, and the Roi-Chevalier (the 'Knight-King')[1] for his personal involvement in the wars against his great rival Emperor Charles V, who was also King of Spain.
+
+Following the policy of his predecessors, Francis continued the Italian Wars. The succession of Charles V to the Burgundian Netherlands, the throne of Spain, and his subsequent election as Holy Roman Emperor meant that France was geographically encircled by the Habsburg monarchy. In his struggle against Imperial hegemony, he sought the support of Henry VIII of England at the Field of the Cloth of Gold.[2] When this was unsuccessful, he formed a Franco-Ottoman alliance with the Muslim sultan Suleiman the Magnificent, a controversial move for a Christian king at the time.[3]
+
+Francis of Orléans was born on 12 September 1494 at the Château de Cognac in the town of Cognac,[1] which at that time lay in the province of Saintonge, a part of the Duchy of Aquitaine.  Today the town lies in the department of Charente.
+
+Francis was the only son of Charles of Orléans, Count of Angoulême, and Louise of Savoy and a great-great-grandson of King Charles V of France.[4] His family was not expected to inherit the throne, as his third cousin King Charles VIII was still young at the time of his birth, as was his father's cousin the Duke of Orléans, later King Louis XII. However, Charles VIII died childless in 1498 and was succeeded by Louis XII, who himself had no male heir.[5] The Salic Law prevented women from inheriting the throne.  Therefore, the four-year-old Francis (who was already Count of Angoulême after the death of his own father two years earlier) became the heir presumptive to the throne of France in 1498 and was vested with the title of Duke of Valois.[5]
+
+In 1505, Louis XII, having fallen ill, ordered that his daughter Claude and Francis be married immediately, but only through an assembly of nobles were the two engaged.[6] Claude was heir presumptive to the Duchy of Brittany through her mother, Anne of Brittany. Following Anne's death, the marriage took place on 18 May 1514.[7] On 1 January 1515, Louis died, and Francis inherited the throne. He was crowned King of France in the Cathedral of Reims on 25 January 1515, with Claude as his queen consort.[8]
+
+As Francis was receiving his education, ideas emerging from the Italian Renaissance were influential in France. Some of his tutors, such as François Desmoulins de Rochefort (his Latin instructor, who later during the reign of Francis was named Grand Aumônier de France) and Christophe de Longueil (a Brabantian humanist), were attracted by these new ways of thinking and attempted to influence Francis. His academic education had been in arithmetic, geography, grammar, history, reading, spelling, and writing and he became proficient in Hebrew, Italian, Latin and Spanish. Francis came to learn chivalry, dancing, and music, and he loved archery, falconry, horseback riding, hunting, jousting, real tennis and wrestling. He ended up reading philosophy and theology and he was fascinated with art, literature, poetry and science. His mother, who had a high admiration for Italian Renaissance art, passed this interest on to her son. Although Francis did not receive a humanist education, he was more influenced by humanism than any previous French king.
+
+By the time he ascended the throne in 1515, the Renaissance had arrived in France, and Francis became an enthusiastic patron of the arts. At the time of his accession, the royal palaces of France were ornamented with only a scattering of great paintings, and not a single sculpture, either ancient or modern. During Francis' reign, the magnificent art collection of the French kings, which can still be seen at the Louvre Palace, was begun.
+
+Francis patronized many great artists of his time, including Andrea del Sarto and Leonardo da Vinci; the latter of whom was persuaded to make France his home during his last years. While da Vinci painted very little during his years in France, he brought with him many of his greatest works, including the Mona Lisa (known in France as La Joconde), and these remained in France after his death. Other major artists to receive Francis' patronage included the goldsmith Benvenuto Cellini and the painters Rosso Fiorentino, Giulio Romano, and Primaticcio, all of whom were employed in decorating Francis' various palaces. He also invited the noted architect Sebastiano Serlio (1475–1554), who enjoyed a fruitful late career in France.[9] Francis also commissioned a number of agents in Italy to procure notable works of art and ship them to France.
+
+Francis was also renowned as a man of letters. When Francis comes up in a conversation among characters in Baldassare Castiglione's Book of the Courtier, it is as the great hope to bring culture to the war-obsessed French nation. Not only did Francis support a number of major writers of the period, he was a poet himself, if not one of particular abilities. Francis worked diligently at improving the royal library. He appointed the great French humanist Guillaume Budé as chief librarian and began to expand the collection. Francis employed agents in Italy to look for rare books and manuscripts, just as he had agents looking for art works. During his reign, the size of the library greatly increased. Not only did he expand the library, there is also evidence[citation needed] that he read the books he bought for it, a much rarer event in the royal annals. Francis set an important precedent by opening his library to scholars from around the world in order to facilitate the diffusion of knowledge.
+
+In 1537, Francis signed the Ordonnance de Montpellier, which decreed that his library be given a copy of every book to be sold in France.  Francis' older sister, Marguerite, Queen of Navarre, was also an accomplished writer who produced the classic collection of short stories known as the Heptameron.  Francis corresponded with the abbess and philosopher Claude de Bectoz, of whose letters he was so fond that he would carry them around and show them to the ladies of his court.[10]
+Together with his sister, he visited her in Tarascon.[11][failed verification]
+
+Francis poured vast amounts of money into new structures. He continued the work of his predecessors on the Château d'Amboise and also started renovations on the Château de Blois. Early in his reign, he began construction of the magnificent Château de Chambord, inspired by the architectural styles of the Italian renaissance, and perhaps even designed by Leonardo da Vinci. Francis rebuilt the Château du Louvre, transforming it from a medieval fortress into a building of Renaissance splendour. He financed the building of a new City Hall (the Hôtel de Ville) for Paris in order to have control over the building's design. He constructed the Château de Madrid in the Bois de Boulogne and rebuilt the Château de Saint-Germain-en-Laye. The largest of Francis' building projects was the reconstruction and expansion of the Château de Fontainebleau, which quickly became his favourite place of residence, as well as the residence of his official mistress, Anne, Duchess of Étampes. Each of Francis' projects was luxuriously decorated both inside and out. Fontainebleau, for instance, had a gushing fountain in its courtyard where quantities of wine were mixed with the water.
+
+Although the Italian Wars (1494–1559) came to dominate the reign of Francis I, the wars were not the sole focus of his policies.  Francis merely continued the incessant wars that his predecessors had started and that his successors on the throne of France would drag on after Francis' death.  Indeed, the Italian Wars had begun when Milan sent a plea to King Charles VIII of France for protection against the aggressive actions of the King of Naples.[12] Militarily and diplomatically, Francis' reign was a mixed bag of success and failure.  Francis tried and failed to become Holy Roman Emperor at the Imperial election of 1519.  However, there were also temporary victories, such as in the portion of the Italian Wars called the War of the League of Cambrai (1508–1516) and, more specifically, to the final stage of that war, which history refers to simply as "Francis' First Italian War" (1515–1516), when Francis routed the combined forces of the Papal States and the Old Swiss Confederacy at Marignano on 13–15 September 1515. This victory at Marignano allowed Francis to capture the Italian city-state of Milan. Later, in November 1521, during the Four Years' War (1521–1526) and facing the advancing Imperial forces of the Holy Roman Empire and open revolt within Milan, Francis was forced to abandon Milan, thus, cancelling the triumph at Marignano.
+
+Much of the military activity of Francis's reign was focused on his sworn enemy, the Holy Roman Emperor Charles V. Francis and Charles maintained an intense personal rivalry. Charles, in fact, brashly challenged Francis to single combat multiple times. In addition to the Holy Roman Empire, Charles personally ruled Spain, Austria, and a number of smaller possessions neighboring France. He was thus a constant threat to Francis' kingdom.
+
+Francis attempted to arrange an alliance with Henry VIII of England at the famous meeting at the Field of Cloth of Gold on 7 June 1520, but despite a lavish fortnight of diplomacy they failed to reach an agreement.[13]
+
+Francis suffered his most devastating defeat at the Battle of Pavia on 24 February 1525, during part of the continuing Italian Wars known as the Four Years' War. Francis was actually captured by the forces of Charles V after Cesare Hercolani was able to injure his horse, leading Francis to be captured by Diego Dávila, Alonso Pita da Veiga and Juan de Urbieta, from Guipúzcoa. For this reason, Hercolani was named "Victor of the battle of Pavia". Zuppa alla Pavese was supposedly invented on the spot to feed the captive king right after the battle.[14] There are allegations that Francis would have been killed by mistake by one of Charles' soldiers had Pedro de Valdivia —the future conqueror of Chile— not intervened.[15]
+
+Francis I was held captive in Madrid. In a letter to his mother he wrote, "Of all things, nothing remains to me but honour and life, which is safe." This line has come down in history famously as "All is lost save honour."[16] In the Treaty of Madrid, signed on 14 January 1526, Francis was forced to make major concessions to Charles V before he was freed on 17 March 1526. An ultimatum from Ottoman Sultan Suleiman to Charles V also played an important role in his release. Among the concessions that Francis I yielded to Charles V were the surrender of any claims to Naples and Milan in Italy.[17] Francis I was also forced to recognise the independence of the duchy of Burgundy, which had become part of France since the death of Charles, Duke of Burgundy on 5 January 1477,[18] during the reign of Louis XI.
+
+Furthermore, France was required to give up all claims to Flanders and the Artois.[17] Additionally, Francis I was allowed to return to France in exchange for his two sons, Francis and Henry, but once he was free he argued that his agreement with Charles was made under duress. He also claimed that the agreement was void because his sons were taken hostage with the implication that his word alone could not be trusted. Thus he firmly repudiated it.
+
+Francis persevered in his hatred of Charles V and desire to control Italy by conquest. The repudiation of the Treaty of Madrid led to the War of the League of Cognac of 1526–30. By the mid-1520s, Pope Clement VII wished to liberate Italy from foreign domination, especially that of Charles V, so to that end he negotiated with Venice to form the League of Cognac. Francis I willingly joined this anti-Imperial league on 22 May 1526.[19]
+
+After the league failed, Francis concluded a secret alliance with the Landgrave of Hesse on 27 January 1534. This was directed against Charles V on the pretext of assisting the Duke of Wurttemberg to regain his traditional seat, from which Charles had removed him in 1519. Francis also obtained the help of the Ottoman Empire and renewed the contest in Italy in the Italian War of 1536–1538 after the death of Francesco II Sforza, the ruler of Milan. This round of fighting, which had little result, was ended by the Truce of Nice. The agreement collapsed, however, which led to Francis' final attempt on Italy in the Italian War of 1542–1546. This time Francis managed to hold off the forces of Charles V and England's Henry VIII. Charles V was forced to sign the Treaty of Crépy because of his financial difficulties and conflicts with the Schmalkaldic League.
+
+Francis had been much aggrieved at the papal bull Aeterni regis: in June 1481 Portuguese rule over Africa and the Indies was confirmed by Pope Sixtus IV. Thirteen years later, on 7 June 1494, Portugal and the Crown of Castille signed the Treaty of Tordesillas under which the newly discovered lands would be divided between the two signatories. All this prompted King Francis to declare, "The sun shines for me as it does for others. I would very much like to see the clause of Adam’s will by which I should be denied my share of the world."[20]
+
+In order to counterbalance the power of the Habsburg Empire under Charles V, especially its control of large parts of the New World through the Crown of Spain, Francis I endeavoured to develop contacts with the New World and Asia. Fleets were sent to the Americas and the Far East, and close contacts were developed with the Ottoman Empire permitting the development of French Mediterranean trade as well as the establishment of a strategic military alliance.
+
+The port city now known as Le Havre was founded in 1517 during the early years of Francis' reign. The construction of a new port was urgently needed in order to replace the ancient harbours of Honfleur and Harfleur, whose utility had decreased due to silting. Le Havre was originally named Franciscopolis after the King who founded it, but this name did not survive into later reigns.
+
+In 1524, Francis assisted the citizens of Lyon in financing the expedition of Giovanni da Verrazzano to North America. On this expedition, Verrazzano visited the present site of New York City, naming it New Angoulême, and claimed Newfoundland for the French crown. Verrazzano's letter to Francis of 8 July 1524 is known as the Cèllere Codex.[21]
+
+In 1531, Bertrand d'Ornesan tried to establish a French trading post at Pernambuco, Brazil.[22]
+
+In 1534, Francis sent Jacques Cartier to explore the St. Lawrence River in Quebec to find "certain islands and lands where it is said there must be great quantities of gold and other riches".[23] In 1541, Francis sent Jean-François de Roberval to settle Canada and to provide for the spread of "the Holy Catholic faith."
+
+French trade with East Asia was initiated during the reign of Francis I with the help of shipowner Jean Ango. In July 1527, a French Norman trading ship from the city of Rouen is recorded by the Portuguese João de Barros as having arrived in the Indian city of Diu.[24] In 1529, Jean Parmentier, on board the Sacre and the Pensée, reached Sumatra.[24][25] Upon its return, the expedition triggered the development of the Dieppe maps, influencing the work of Dieppe cartographers such as Jean Rotz.[26]
+
+Under the reign of Francis I, France became the first country in Europe to establish formal relations with the Ottoman Empire and to set up instruction in the Arabic language under the guidance of Guillaume Postel at the Collège de France.[27]
+
+In a watershed moment in European diplomacy, Francis came to an understanding with the Ottoman Empire that developed into a Franco-Ottoman alliance. The alliance has been called "the first nonideological diplomatic alliance of its kind between a Christian and non-Christian empire".[28] It did, however, cause quite a scandal in the Christian world[29] and was designated "the impious alliance", or "the sacrilegious union of the [French] Lily and the [Ottoman] Crescent." Nevertheless, it endured for many years, since it served the objective interests of both parties.[30] The two powers colluded against Charles V, and in 1543 they even combined for a joint naval assault in the Siege of Nice.
+
+In 1533, Francis I sent colonel Pierre de Piton as ambassador to Morocco, initiating official France-Morocco relations.[31] In a letter to Francis I dated 13 August 1533, the Wattassid ruler of Fez, Ahmed ben Mohammed, welcomed French overtures and granted freedom of shipping and protection of French traders.
+
+Francis took several steps to eradicate the monopoly of Latin as the language of knowledge. In 1530, he declared French the national language of the kingdom, and that same year opened the Collège des trois langues, or Collège Royal, following the recommendation of humanist Guillaume Budé. Students at the Collège could study Greek, Hebrew and Aramaic, then Arabic under Guillaume Postel beginning in 1539.[32]
+
+In 1539, in his castle in Villers-Cotterêts,[33] Francis signed the important edict known as Ordinance of Villers-Cotterêts, which, among other reforms, made French the administrative language of the kingdom as a replacement for Latin. This same edict required priests to register births, marriages, and deaths, and to establish a registry office in every parish. This initiated the first records of vital statistics with filiations available in Europe.
+
+Divisions in Christianity in Western Europe during Francis' reign created lasting international rifts. Martin Luther's preaching and writing sparked the Protestant Reformation, which spread through much of Europe, including France.
+
+Initially, Francis was relatively tolerant of the new movement, under the influence of his beloved sister Marguerite de Navarre, who was genuinely attracted by Luther's theology. He even considered it politically useful, as it caused many German princes to turn against his enemy Charles V. In 1533 Francis even dared to suggest to Pope Clement VII that he convene a church council in which Catholic and Protestant rulers would have an equal vote in order to settle their differences – an offer rejected by both the Pope and Charles V. Beginning in 1523, however, Francis burned several heretics at the Place Maubert.[34]
+
+Francis' attitude towards Protestantism changed for the worse following the "Affair of the Placards", on the night of 17 October 1534, in which notices appeared on the streets of Paris and other major cities denouncing the Catholic mass. The most fervent Catholics were outraged by the notice's allegations. Francis himself came to view the movement as a plot against him and began to persecute its followers. Protestants were jailed and executed. In some areas whole villages were destroyed. In Paris, after 1540, Francis had heretics such as Etienne Dolet tortured and burned.[35] Printing was censored and leading Protestant reformers such as John Calvin were forced into exile. The persecutions soon numbered thousands of dead and tens of thousands of homeless.[36]
+
+Persecutions against Protestants were codified in the Edict of Fontainebleau (1540) issued by Francis. Major acts of violence continued, as when Francis ordered the execution of one of the historical pre-Lutheran groups, the Waldensians, at the Massacre of Mérindol in 1545.
+
+Francis died at the Château de Rambouillet on 31 March 1547, on his son and successor's 28th birthday. It is said that "he died complaining about the weight of a crown that he had first perceived as a gift from God".[37] He was interred with his first wife, Claude, Duchess of Brittany, in Saint Denis Basilica. He was succeeded by his son, Henry II.
+
+Francis' tomb and that of his wife and mother, along with the tombs of other French kings and members of the royal family, were desecrated on 20 October 1793 during the Reign of Terror at the height of the French Revolution.
+
+Francis' personal emblem was the salamander and his Latin motto was Nutrisco et extinguo ("I nourish [the good] and extinguish [the bad]").[citation needed]
+
+His long nose earned him the nickname François du Grand Nez ("Francis of the Big Nose"), he was also colloquially known as the "Grand Colas" or "Bonhomme Colas". For his personal involvement in battles, he was known as le Roi-Chevalier ("the Knight-King") or the le Roi-Guerrier ("the Warrior-King").[38]
+
+On 18 May 1514, Francis married his second cousin Claude, the daughter of King Louis XII of France and Duchess Anne of Brittany. The couple had seven children:
+
+On 7 July 1530, Francis I married his second wife Eleanor of Austria,[39] 
+a sister of the Emperor Charles V. The couple had no children. During his reign, Francis kept two official mistresses at court. The first was Françoise de Foix, Countess of Châteaubriant. In 1526, she was replaced by the blonde-haired, cultured Anne de Pisseleu d'Heilly, Duchess of Étampes who, with the death of Queen Claude two years earlier, wielded far more political power at court than her predecessor had done. Another of his earlier mistresses was allegedly Mary Boleyn, mistress of King Henry VIII and sister of Henry's future wife, Anne Boleyn.[40]
+
+The amorous exploits of Francis inspired the 1832 play by Fanny Kemble, Francis the First, and the 1832 play by Victor Hugo, Le Roi s'amuse ("The King's Amusement"), which featured the jester Triboulet, the inspiration for the 1851 opera Rigoletto by Giuseppe Verdi.
+
+Francis was first played in a George Méliès movie by an unknown actor in 1907, and has also been played by Claude Garry (1910), Aimé Simon-Girard (1937), Sacha Guitry (1937), Gérard Oury (1953), Jean Marais (1955), Pedro Armendáriz (1956), Claude Titre (1962), Bernard Pierre Donnadieu (1990). Timothy West (1998) and Emmanuel Leconte (2007– 2010).
+
+Francis was portrayed by Peter Gilmore in the comedy film Carry On Henry charting the fictitious two extra wives of Henry VIII (including Marie cousin of King Francis).
+
+Francis receives a mention in a minor story in Laurence Sterne's novel Tristram Shandy. The narrator claims that the king, wishing to win the favour of Switzerland, offers to make the country the godmother of his son. When, however, their choice of name conflicts, he declares war.
+
+He is also mentioned in Jean de la Brète's novel Reine – Mon oncle et mon curé, where the main character Reine de Lavalle idolises him after reading his biography, much to the dismay of the local priest.
+
+He often receives mentions in novels on the lives of either of the Boleyn sisters – Mary Boleyn (d. 1543) and her sister, Queen Anne Boleyn (executed 1536), both of whom were for a time educated at his court. Mary had, according to several accounts, been Francis' one-time mistress and Anne had been a favourite of his sister: the novels The Lady in the Tower, The Other Boleyn Girl, The Last Boleyn, Dear Heart, How Like You This? and Mademoiselle Boleyn feature Francis in their story. He appears in Hilary Mantel's Wolf Hall about Henry VIII's minister Thomas Cromwell and is often referred to in its sequel, Bring Up the Bodies.
+
+Francis is portrayed in Diane Haeger's novel Courtesan about Diane de Poitiers and Henri II.
+
+Francis appears as the patron of Benvenuto Cellini in the 1843 French novel L'Orfèvre du roi, ou Ascanio by Alexandre Dumas, père.
+
+Samuel Shellabarger's novel The King's Cavalier describes Francis the man, and the cultural and political circumstances of his reign, in some detail.
+
+He was a recurring character in the Showtime series The Tudors, opposite Jonathan Rhys Meyers as Henry VIII and Natalie Dormer as Anne Boleyn. Francis is played by French actor, Emmanuel Leconte.
+
+He and his court set the scene for Friedrich Schiller's ballad Der Handschuh (The Glove).
+
+Francis I (played by Timothy West) and Francis's son Henry II (played by Dougray Scott) are central figures in the 1998 movie Ever After, a retelling of the Cinderella story.  The plot includes Leonardo da Vinci (played by Patrick Godfrey) arriving at Francis's court with the Mona Lisa.
+
+He is played by Alfonso Bassave in the TVE series Carlos, rey emperador, opposite Álvaro Cervantes as Charles V.

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+
+
+
+The Colosseum or Coliseum (/ˌkɒləˈsiːəm/ KOL-ə-SEE-əm), also known as the Flavian Amphitheatre (Latin: Amphitheatrum Flavium; Italian: Anfiteatro Flavio [aɱfiteˈaːtro ˈflaːvjo] or Colosseo [kolosˈsɛːo]), is an oval amphitheatre in the centre of the city of Rome, Italy. Built of travertine limestone, tuff (volcanic rock), and brick-faced concrete,[1] it was the largest amphitheatre ever built at the time and held 50,000 to 80,000 spectators. The Colosseum is situated just east of the Roman Forum. Construction began under the emperor Vespasian in AD 72[2] and was completed in AD 80 under his successor and heir, Titus.[3] Further modifications were made during the reign of Domitian (81–96).[4] These three emperors are known as the Flavian dynasty, and the amphitheatre was named in Latin for its association with their family name (Flavius).
+
+The Colosseum could hold an estimated 50,000 to 80,000 spectators at various points of its history over the centuries,[5][6] having an average audience of some 65,000;[7][8] it was used for gladiatorial contests and public spectacles such as mock sea battles (for only a short time as the hypogeum was soon filled in with mechanisms to support the other activities), animal hunts, executions, re-enactments of famous battles, and dramas based on Roman mythology. The building ceased to be used for entertainment in the early medieval era. It was later reused for such purposes as housing, workshops, quarters for a religious order, a fortress, a quarry, and a Christian shrine.[citation needed]
+
+Although substantially ruined because of earthquakes and stone-robbers, the Colosseum is still an iconic symbol of Imperial Rome and is listed as one of the New7Wonders of the World.[9] It is one of Rome's most popular tourist attractions and also has links to the Roman Catholic Church, as each Good Friday the Pope leads a torchlit "Way of the Cross" procession that starts in the area around the Colosseum.[10]
+
+The Colosseum is also depicted on the Italian version of the five-cent euro coin.
+
+The Colosseum's original Latin name was Amphitheatrum Flavium, often anglicized as Flavian Amphitheatre.[11] The building was constructed by emperors of the Flavian dynasty, following the reign of Nero.[12] This name is still used in modern English, but generally the structure is better known as the Colosseum. In antiquity, Romans may have referred to the Colosseum by the unofficial name Amphitheatrum Caesareum (with Caesareum an adjective pertaining to the title Caesar), but this name may have been strictly poetic[13][14] as it was not exclusive to the Colosseum; Vespasian and Titus, builders of the Colosseum, also constructed an amphitheater of the same name in Puteoli (modern Pozzuoli).[15]
+
+The name Colosseum is believed to be derived from a colossal statue of Nero that once stood nearby.[4] This statue was later remodeled by Nero's successors into the likeness of Helios (Sol) or Apollo, the sun god, by adding the appropriate solar crown. It was then commonly referred to as the "Colossus solis". Nero's head was also replaced several times with the heads of succeeding emperors. Despite its pagan links, the statue remained standing well into the medieval era and was credited with magical powers. It came to be seen as an iconic symbol of the permanence of Rome.
+
+In the 8th century, an epigram attributed to the Venerable Bede celebrated the symbolic significance of the statue in a prophecy that is variously quoted: Quamdiu stat Colisæus, stat et Roma; quando cadet colisæus, cadet et Roma; quando cadet Roma, cadet et mundus ("as long as the Colossus stands, so shall Rome; when the Colossus falls, Rome shall fall; when Rome falls, so falls the world").[16] This is often mistranslated to refer to the Colosseum rather than the Colossus (as in, for instance, Byron's poem Childe Harold's Pilgrimage). However, at the time that the Pseudo-Bede wrote, the masculine noun coliseus was applied to the statue rather than to what was still known as the Flavian amphitheatre.
+
+The Colossus did eventually fall, possibly being pulled down to reuse its bronze. By the year 1000 the name "Colosseum" had been coined to refer to the amphitheatre from the nearby "Colossus Solis".[17] The statue itself was largely forgotten and only its base survives, situated between the Colosseum and the nearby Temple of Venus and Roma.[18]
+
+The name further evolved to Coliseum during the Middle Ages[citation needed]. In Italy, the amphitheatre is still known as il Colosseo, and other Romance languages have come to use similar forms such as Coloseumul (Romanian), le Colisée (French), el Coliseo (Spanish) and o Coliseu (Portuguese).
+
+The site chosen was a flat area on the floor of a low valley between the Caelian, Esquiline and Palatine Hills, through which a canalised stream ran as well as an artificial lake/marsh.[19] By the 2nd century BC the area was densely inhabited. It was devastated by the Great Fire of Rome in 64 AD, following which Nero seized much of the area to add to his personal domain. He built the grandiose Domus Aurea on the site, in front of which he created an artificial lake surrounded by pavilions, gardens and porticoes. The existing Aqua Claudia aqueduct was extended to supply water to the area and the gigantic bronze Colossus of Nero was set up nearby at the entrance to the Domus Aurea.[18]
+
+Although the Colossus was preserved, much of the Domus Aurea was torn down. The lake was filled in and the land reused as the location for the new Flavian Amphitheatre. Gladiatorial schools and other support buildings were constructed nearby within the former grounds of the Domus Aurea. Vespasian's decision to build the Colosseum on the site of Nero's lake can be seen as a populist gesture of returning to the people an area of the city which Nero had appropriated for his own use. In contrast to many other amphitheatres, which were located on the outskirts of a city, the Colosseum was constructed in the city centre, in effect, placing it both symbolically and precisely at the heart of Rome.
+
+Construction was funded by the opulent spoils taken from the Jewish Temple after the First Jewish–Roman War in 70 CE led to the Siege of Jerusalem. According to a reconstructed inscription found on the site, "the emperor Vespasian ordered this new amphitheatre to be erected from his general's share of the booty." It is often assumed that Jewish prisoners of war were brought back to Rome and contributed to the massive workforce needed for the construction of the amphitheatre, but there is no ancient evidence for that; it would, nonetheless, be commensurate with Roman practice to add humiliation to the defeated population.[20] Along with this free source of unskilled labor, teams of professional Roman builders, engineers, artists, painters and decorators undertook the more specialized tasks necessary for building the Colosseum. The Colosseum was constructed with several different materials: wood, limestone, tuff, tiles, cement, and mortar.
+
+Construction of the Colosseum began under the rule of Vespasian[4] in around 70–72 AD (73–75 AD according to some sources). The Colosseum had been completed up to the third story by the time of Vespasian's death in 79. The top level was finished by his son, Titus, in 80,[4] and the inaugural games were held in 80 or 81 AD.[21] Dio Cassius recounts that over 9,000 wild animals were killed during the inaugural games of the amphitheatre. Commemorative coinage was issued celebrating the inauguration.[22] The building was remodelled further under Vespasian's younger son, the newly designated Emperor Domitian, who constructed the hypogeum, a series of tunnels used to house animals and slaves. He also added a gallery to the top of the Colosseum to increase its seating capacity.[23]
+
+In 217, the Colosseum was badly damaged by a major fire (caused by lightning, according to Dio Cassius[24]) which destroyed the wooden upper levels of the amphitheatre's interior. It was not fully repaired until about 240 and underwent further repairs in 250 or 252 and again in 320. Gladiatorial fights are last mentioned around 435.[citation needed] An inscription records the restoration of various parts of the Colosseum under Theodosius II and Valentinian III (reigned 425–455), possibly to repair damage caused by a major earthquake in 443; more work followed in 484[25] and 508. The arena continued to be used for contests well into the 6th century. Animal hunts continued until at least 523, when Anicius Maximus celebrated his consulship with some venationes, criticised by King Theodoric the Great for their high cost.[18]
+
+The Colosseum underwent several radical changes of use. By the late 6th century a small chapel had been built into the structure of the amphitheater, though this apparently did not confer any particular religious significance on the building as a whole. The arena was converted into a cemetery. The numerous vaulted spaces in the arcades under the seating were converted into housing and workshops, and are recorded as still being rented out as late as the 12th century. Around 1200 the Frangipani family took over the Colosseum and fortified it, apparently using it as a castle.
+
+Severe damage was inflicted on the Colosseum by the great earthquake in 1349, causing the outer south side, lying on a less stable alluvial terrain, to collapse. Much of the tumbled stone was reused to build palaces, churches, hospitals and other buildings elsewhere in Rome. A religious order moved into the northern third of the Colosseum in the mid-14th century[26] and continued to inhabit it until as late as the early 19th century. The interior of the amphitheater was extensively stripped of stone, which was reused elsewhere, or (in the case of the marble façade) was burned to make quicklime.[18] The bronze clamps which held the stonework together were pried or hacked out of the walls, leaving numerous pockmarks which still scar the building today.
+
+During the 16th and 17th century, Church officials sought a productive role for the Colosseum. Pope Sixtus V (1585–1590) planned to turn the building into a wool factory to provide employment for Rome's prostitutes, though this proposal fell through with his premature death.[27] In 1671 Cardinal Altieri authorized its use for bullfights; a public outcry caused the idea to be hastily abandoned.
+
+In 1749, Pope Benedict XIV endorsed the view that the Colosseum was a sacred site where early Christians had been martyred. He forbade the use of the Colosseum as a quarry and consecrated the building to the Passion of Christ and installed Stations of the Cross, declaring it sanctified by the blood of the Christian martyrs who perished there (see Significance in Christianity). However, there is no historical evidence to support Benedict's claim, nor is there even any evidence that anyone before the 16th century suggested this might be the case; the Catholic Encyclopedia concludes that there are no historical grounds for the supposition, other than the reasonably plausible conjecture that some of the many martyrs may well have been.[28]
+
+Later popes initiated various stabilization and restoration projects, removing the extensive vegetation which had overgrown the structure and threatened to damage it further. The façade was reinforced with triangular brick wedges in 1807 and 1827, and the interior was repaired in 1831, 1846 and in the 1930s. The arena substructure was partly excavated in 1810–1814 and 1874 and was fully exposed under Benito Mussolini in the 1930s.[18]
+
+The Colosseum is today one of Rome's most popular tourist attractions, receiving millions of visitors annually. The effects of pollution and general deterioration over time prompted a major restoration programme carried out between 1993 and 2000, at a cost of 40 billion Italian lire ($19.3m / €20.6m at 2000 prices).
+
+In recent years, the Colosseum has become a symbol of the international campaign against capital punishment, which was abolished in Italy in 1948. Several anti–death penalty demonstrations took place in front of the Colosseum in 2000. Since that time, as a gesture against the death penalty, the local authorities of Rome change the color of the Colosseum's night time illumination from white to gold whenever a person condemned to the death penalty anywhere in the world gets their sentence commuted or is released,[29] or if a jurisdiction abolishes the death penalty. Most recently, the Colosseum was illuminated in gold in November 2012 following the abolishment of capital punishment in the American state of Connecticut in April 2012.[30]
+
+Because of the ruined state of the interior, it is impractical to use the Colosseum to host large events; only a few hundred spectators can be accommodated in temporary seating. However, much larger concerts have been held just outside, using the Colosseum as a backdrop. Performers who have played at the Colosseum in recent years have included Ray Charles (May 2002),[31] Paul McCartney (May 2003),[32] Elton John (September 2005),[33] and Billy Joel (July 2006).
+
+Unlike earlier Greek theatres that were built into hillsides, the Colosseum is an entirely free-standing structure. It derives its basic exterior and interior architecture from that of two Roman theatres back to back. It is elliptical in plan and is 189 meters (615 ft / 640 Roman feet) long, and 156 meters (510 ft / 528 Roman feet) wide, with a base area of 24,000 square metres (6 acres). The height of the outer wall is 48 meters (157 ft / 165 Roman feet). The perimeter originally measured 545 meters (1,788 ft / 1,835 Roman feet). The central arena is an oval 87 m (287 ft) long and 55 m (180 ft) wide, surrounded by a wall 5 m (15 ft) high, above which rose tiers of seating.
+
+The outer wall is estimated to have required over 100,000 cubic metres (3,531,467 cubic feet) of travertine stone which were set without mortar; they were held together by 300 tons of iron clamps.[18] However, it has suffered extensive damage over the centuries, with large segments having collapsed following earthquakes. The north side of the perimeter wall is still standing; the distinctive triangular brick wedges at each end are modern additions, having been constructed in the early 19th century to shore up the wall. The remainder of the present-day exterior of the Colosseum is in fact the original interior wall.
+
+The surviving part of the outer wall's monumental façade comprises three stories of superimposed arcades surmounted by a podium on which stands a tall attic, both of which are pierced by windows interspersed at regular intervals. The arcades are framed by half-columns of the Doric, Ionic, and Corinthian orders, while the attic is decorated with Corinthian pilasters.[34] Each of the arches in the second- and third-floor arcades framed statues, probably honoring divinities and other figures from Classical mythology.
+
+Two hundred and forty mast corbels were positioned around the top of the attic. They originally supported a retractable awning, known as the velarium, that kept the sun and rain off spectators. This consisted of a canvas-covered, net-like structure made of ropes, with a hole in the center.[4] It covered two-thirds of the arena, and sloped down towards the center to catch the wind and provide a breeze for the audience. Sailors, specially enlisted from the Roman naval headquarters at Misenum and housed in the nearby Castra Misenatium, were used to work the velarium.[35]
+
+The Colosseum's huge crowd capacity made it essential that the venue could be filled or evacuated quickly. Its architects adopted solutions very similar to those used in modern stadiums to deal with the same problem. The amphitheatre was ringed by eighty entrances at ground level, 76 of which were used by ordinary spectators.[4] Each entrance and exit was numbered, as was each staircase. The northern main entrance was reserved for the Roman Emperor and his aides, whilst the other three axial entrances were most likely used by the elite. All four axial entrances were richly decorated with painted stucco reliefs, of which fragments survive. Many of the original outer entrances have disappeared with the collapse of the perimeter wall, but entrances XXIII (23) to LIIII (54) survive.[18]
+
+Spectators were given tickets in the form of numbered pottery shards, which directed them to the appropriate section and row. They accessed their seats via vomitoria (singular vomitorium), passageways that opened into a tier of seats from below or behind. These quickly dispersed people into their seats and, upon conclusion of the event or in an emergency evacuation, could permit their exit within only a few minutes. The name vomitoria derived from the Latin word for a rapid discharge, from which English derives the word vomit.
+
+According to the Codex-Calendar of 354, the Colosseum could accommodate 87,000 people, although modern estimates put the figure at around 50,000. They were seated in a tiered arrangement that reflected the rigidly stratified nature of Roman society. Special boxes were provided at the north and south ends respectively for the Emperor and the Vestal Virgins, providing the best views of the arena. Flanking them at the same level was a broad platform or podium for the senatorial class, who were allowed to bring their own chairs. The names of some 5th century senators can still be seen carved into the stonework, presumably reserving areas for their use.
+
+The tier above the senators, known as the maenianum primum, was occupied by the non-senatorial noble class or knights (equites). The next level up, the maenianum secundum, was originally reserved for ordinary Roman citizens (plebeians) and was divided into two sections. The lower part (the immum) was for wealthy citizens, while the upper part (the summum) was for poor citizens. Specific sectors were provided for other social groups: for instance, boys with their tutors, soldiers on leave, foreign dignitaries, scribes, heralds, priests and so on. Stone (and later marble) seating was provided for the citizens and nobles, who presumably would have brought their own cushions with them. Inscriptions identified the areas reserved for specific groups.
+
+Another level, the maenianum secundum in legneis, was added at the very top of the building during the reign of Domitian. This comprised a gallery for the common poor, slaves and women. It would have been either standing room only, or would have had very steep wooden benches. Some groups were banned altogether from the Colosseum, notably gravediggers, actors and former gladiators.[18]
+
+Each tier was divided into sections (maeniana) by curved passages and low walls (praecinctiones or baltei), and were subdivided into cunei, or wedges, by the steps and aisles from the vomitoria. Each row (gradus) of seats was numbered, permitting each individual seat to be exactly designated by its gradus, cuneus, and number.[36]
+
+The arena itself was 83 meters by 48 meters (272 ft by 157 ft / 280 by 163 Roman feet).[18] It comprised a wooden floor covered by sand (the Latin word for sand is harena or arena), covering an elaborate underground structure called the hypogeum (literally meaning "underground"). The hypogeum was not part of the original construction but was ordered to be built by Emperor Domitian. Little now remains of the original arena floor, but the hypogeum is still clearly visible. It consisted of a two-level subterranean network of tunnels and cages beneath the arena where gladiators and animals were held before contests began. Eighty vertical shafts provided instant access to the arena for caged animals and scenery pieces concealed underneath; larger hinged platforms, called hegmata, provided access for elephants and the like. It was restructured on numerous occasions; at least twelve different phases of construction can be seen.[18]
+
+The hypogeum was connected by tunnels to a number of points outside the Colosseum. Animals and performers were brought through the tunnel from nearby stables, with the gladiators' barracks at the Ludus Magnus to the east also being connected by tunnels. Separate tunnels were provided for the Emperor and the Vestal Virgins to permit them to enter and exit the Colosseum without needing to pass through the crowds.[18]
+
+Substantial quantities of machinery also existed in the hypogeum. Elevators and pulleys raised and lowered scenery and props, as well as lifting caged animals to the surface for release. There is evidence for the existence of major hydraulic mechanisms[18] and according to ancient accounts, it was possible to flood the arena rapidly, presumably via a connection to a nearby aqueduct. However, the construction of the hypogeum at Domitian's behest put an end to the practise of flooding, and thus also to naval battles, early in the Colosseum's existence.
+
+The Colosseum and its activities supported a substantial industry in the area. In addition to the amphitheatre itself, many other buildings nearby were linked to the games. Immediately to the east is the remains of the Ludus Magnus, a training school for gladiators. This was connected to the Colosseum by an underground passage, to allow easy access for the gladiators. The Ludus Magnus had its own miniature training arena, which was itself a popular attraction for Roman spectators. Other training schools were in the same area, including the Ludus Matutinus (Morning School), where fighters of animals were trained, plus the Dacian and Gallic Schools.
+
+Also nearby were the Armamentarium, comprising an armory to store weapons; the Summum Choragium, where machinery was stored; the Sanitarium, which had facilities to treat wounded gladiators; and the Spoliarium, where bodies of dead gladiators were stripped of their armor and disposed of.
+
+Around the perimeter of the Colosseum, at a distance of 18 m (59 ft) from the perimeter, was a series of tall stone posts, with five remaining on the eastern side. Various explanations have been advanced for their presence; they may have been a religious boundary, or an outer boundary for ticket checks, or an anchor for the velarium or awning.[18]
+
+Right next to the Colosseum is also the Arch of Constantine.
+
+The Colosseum was used to host gladiatorial shows as well as a variety of other events. The shows, called munera, were always given by private individuals rather than the state. They had a strong religious element but were also demonstrations of power and family prestige, and were immensely popular with the population. Another popular type of show was the animal hunt, or venatio. This utilized a great variety of wild beasts, mainly imported from Africa and the Middle East, and included creatures such as rhinoceros, hippopotamuses, elephants, giraffes, aurochs, wisents, Barbary lions, panthers, leopards, bears, Caspian tigers, crocodiles and ostriches. Battles and hunts were often staged amid elaborate sets with movable trees and buildings. Such events were occasionally on a huge scale; Trajan is said to have celebrated his victories in Dacia in 107 with contests involving 11,000 animals and 10,000 gladiators over the course of 123 days. During lunch intervals, executions ad bestias would be staged. Those condemned to death would be sent into the arena, naked and unarmed, to face the beasts of death which would literally tear them to pieces.  Other performances would also take place by acrobats and magicians, typically during the intervals.
+
+During the early days of the Colosseum, ancient writers recorded that the building was used for naumachiae (more properly known as navalia proelia) or simulated sea battles. Accounts of the inaugural games held by Titus in AD 80 describe it being filled with water for a display of specially trained swimming horses and bulls. There is also an account of a re-enactment of a famous sea battle between the Corcyrean (Corfiot) Greeks and the Corinthians. This has been the subject of some debate among historians; although providing the water would not have been a problem, it is unclear how the arena could have been waterproofed, nor would there have been enough space in the arena for the warships to move around. It has been suggested that the reports either have the location wrong, or that the Colosseum originally featured a wide floodable channel down its central axis (which would later have been replaced by the hypogeum).[18]
+
+Sylvae or recreations of natural scenes were also held in the arena. Painters, technicians and architects would construct a simulation of a forest with real trees and bushes planted in the arena's floor, and animals would then be introduced. Such scenes might be used simply to display a natural environment for the urban population, or could otherwise be used as the backdrop for hunts or dramas depicting episodes from mythology. They were also occasionally used for executions in which the hero of the story – played by a condemned person – was killed in one of various gruesome but mythologically authentic ways, such as being mauled by beasts or burned to death.
+
+The Colosseum today is now a major tourist attraction in Rome with thousands of tourists each year entering to view the interior arena.[37] There is now a museum dedicated to Eros located in the upper floor of the outer wall of the building. Part of the arena floor has been re-floored. Beneath the Colosseum, a network of subterranean passageways once used to transport wild animals and gladiators to the arena opened to the public in summer 2010.[38]
+
+The Colosseum is also the site of Roman Catholic ceremonies in the 20th and 21st centuries. For instance, Pope Benedict XVI led the Stations of the Cross called the Scriptural Way of the Cross (which calls for more meditation) at the Colosseum[39][40] on Good Fridays.[10]
+
+In 2011 Diego Della Valle, head of the shoe firm Tod's, entered into an agreement with local officials to sponsor a €25 million restoration of the Colosseum. Work was planned to begin at the end of 2011, taking up to two and a half years.[41] Due to the controversial nature of using a public–private partnership to fund the restoration, work was delayed and began in 2013. The restoration is the first full cleaning and repair in the Colosseum's history.[42] The first stage is to clean and restore the Colosseum's arcaded façade and replace the metal enclosures that block the ground-level arches. Taking three years, the final product of this work was unveiled 1 July 2016, when the Italian minister of culture, Dario Franceschini, also announced that the funds have been committed to replace the floors by the end of 2018. These will provide a stage that Franceschini says will be used for "cultural events of the highest level."[43] The project also plans to create a services center and to restore the galleries and underground spaces inside the Colosseum.[44] New to tours of the restored marvel beginning 1 November 2017, the top two levels have been opened for guided visits. The fourth level held the marketplace, and the top fifth tier is where the poorest citizens, the plebeians, gathered and watched the show, bringing picnics for the day-long event.[45]
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+Colosseum 2013
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+Colosseum 2013
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+Colosseum 2012
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+Colosseum 2013
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+Colosseum 2013
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+Colosseum 2013
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+Colosseum 2013
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+Colosseum 2014
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+Colosseum 2018
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+Colosseum 2020
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+The Colosseum is generally regarded by Christians as a site of the martyrdom of large numbers of believers during the persecution of Christians in the Roman Empire, as evidenced by Church history and tradition.[46][47][48] On the other hand, other scholars believe that the majority of martyrdoms may have occurred at other venues within the city of Rome, rather than at the Colosseum, citing a lack of still-intact physical evidence or historical records.[49][50][51] These scholars assert that "some Christians were executed as common criminals in the Colosseum—their crime being refusal to reverence the Roman gods", but most Christian martyrs of the early Church were executed for their faith at the Circus Maximus.[52][53] According to Irenæus (died about 202), Ignatius of Antioch was fed to the lions in Rome around 107 A.D and although Irenaeus says nothing about this happening at the Colosseum, tradition ascribes it to that place.[54][55][56][57]
+
+In the Middle Ages, the Colosseum was not regarded as a monument, and was used as what some modern sources label a "quarry,"[58] which is to say that stones from the Colosseum were taken for the building of other sacred sites.[59] This fact is used to support the idea that, at a time when sites associated with martyrs were highly venerated the Colosseum was not being treated as a sacred site.[60] It was not included in the itineraries compiled for the use of pilgrims nor in works such as the 12th century Mirabilia Urbis Romae ("Marvels of the City of Rome"), which claims the Circus Flaminius – but not the Colosseum – as the site of martyrdoms.[61] Part of the structure was inhabited by a Christian religious order, but it is not known whether this was for any particular religious reason.
+
+Pope Pius V (1566–1572) is said to have recommended that pilgrims gather sand from the arena of the Colosseum to serve as a relic, on the grounds that it was impregnated with the blood of martyrs, although some of his contemporaries did not share his conviction.[62] A century later Fioravante Martinelli listed the Colosseum at the head of a list of places sacred to the martyrs in his 1653 book Roma ex ethnica sacra. Martinelli's book evidently had an effect on public opinion; in response to Cardinal Altieri's proposal some years later to turn the Colosseum into a bullring, Carlo Tomassi published a pamphlet in protest against what he regarded as an act of desecration. The ensuing controversy persuaded Pope Clement X to close the Colosseum's external arcades and declare it a sanctuary.[63]
+
+At the insistence of St. Leonard of Port Maurice, Pope Benedict XIV (1740–1758) forbade the quarrying of the Colosseum and erected Stations of the Cross around the arena, which remained until February 1874.[64] Benedict Joseph Labre spent the later years of his life within the walls of the Colosseum, living on alms, before he died in 1783.[64] Several 19th century popes funded repair and restoration work on the Colosseum, and it still retains its Christian connection today. A Christian cross stands in the Colosseum, with a plaque, stating:
+
+The amphitheater, one consecrated to triumphs, entertainments, and the impious worship of pagan gods, is now dedicated to the sufferings of the martyrs purified from impious superstitions.[54]
+
+Other Christian crosses stand in several points around the arena and every Good Friday the Pope leads a Via Crucis procession to the amphitheater.
+
+The Colosseum has a wide and well-documented history of flora ever since Domenico Panaroli made the first catalogue of its plants in 1643. Since then, 684 species have been identified there. The peak was in 1855 (420 species). Attempts were made in 1871 to eradicate the vegetation, because of concerns over the damage that was being caused to the masonry, but much of it has returned.[18] 242 species have been counted today and of the species first identified by Panaroli, 200 remain.
+
+The variation of plants can be explained by the change of climate in Rome through the centuries. Additionally, bird migration, flower blooming, and the growth of Rome that caused the Colosseum to become embedded within the modern city centre rather than on the outskirts of the ancient city, as well as deliberate transport of species, are also contributing causes. Another reason often given is their seeds being unwittingly transported either on the fur or in the feces of animals brought there from all corners of the empire.[65]
+
+The iconic status of the Colosseum has led it to be featured in numerous films, such as Roman Holiday, Demetrius and the Gladiators, 20 Million Miles to Earth, Way of the Dragon, Gladiator (in which it was re-created via CGI), Megiddo: The Omega Code 2, The Core, The Lizzie McGuire Movie,  Jumper, and the animated movie Madagascar 3: Europe's Most Wanted.
+
+It was also featured in the 1998 The Rise of Rome expansion for the video game Age of Empires, and in the 2010 video game Assassin's Creed: Brotherhood.
+
+The finale of JoJo's Bizarre Adventure: Vento Aureo, in both the anime and manga, takes place in the Colosseum.
+
+Coordinates: 41°53′25″N 12°29′33″E / 41.8902°N 12.4924°E / 41.8902; 12.4924

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+Francis I (French: François Ier; Middle French: Francoys; 12 September 1494 – 31 March 1547) was King of France from 1515 until his death in 1547. He was the son of Charles, Count of Angoulême, and Louise of Savoy. He succeeded his first cousin once removed and father-in-law Louis XII, who died without a son.
+
+A prodigious patron of the arts, he initiated the French Renaissance by attracting many Italian artists to work for him, including Leonardo da Vinci, who brought the Mona Lisa with him, which Francis had acquired. Francis' reign saw important cultural changes with the rise of absolute monarchy in France, the spread of humanism and Protestantism, and the beginning of French exploration of the New World. Jacques Cartier and others claimed lands in the Americas for France and paved the way for the expansion of the first French colonial empire.
+
+For his role in the development and promotion of a standardized French language, he became known as le Père et Restaurateur des Lettres (the 'Father and Restorer of Letters').[1] He was also known as François du Grand Nez ('Francis of the Large Nose'), the Grand Colas, and the Roi-Chevalier (the 'Knight-King')[1] for his personal involvement in the wars against his great rival Emperor Charles V, who was also King of Spain.
+
+Following the policy of his predecessors, Francis continued the Italian Wars. The succession of Charles V to the Burgundian Netherlands, the throne of Spain, and his subsequent election as Holy Roman Emperor meant that France was geographically encircled by the Habsburg monarchy. In his struggle against Imperial hegemony, he sought the support of Henry VIII of England at the Field of the Cloth of Gold.[2] When this was unsuccessful, he formed a Franco-Ottoman alliance with the Muslim sultan Suleiman the Magnificent, a controversial move for a Christian king at the time.[3]
+
+Francis of Orléans was born on 12 September 1494 at the Château de Cognac in the town of Cognac,[1] which at that time lay in the province of Saintonge, a part of the Duchy of Aquitaine.  Today the town lies in the department of Charente.
+
+Francis was the only son of Charles of Orléans, Count of Angoulême, and Louise of Savoy and a great-great-grandson of King Charles V of France.[4] His family was not expected to inherit the throne, as his third cousin King Charles VIII was still young at the time of his birth, as was his father's cousin the Duke of Orléans, later King Louis XII. However, Charles VIII died childless in 1498 and was succeeded by Louis XII, who himself had no male heir.[5] The Salic Law prevented women from inheriting the throne.  Therefore, the four-year-old Francis (who was already Count of Angoulême after the death of his own father two years earlier) became the heir presumptive to the throne of France in 1498 and was vested with the title of Duke of Valois.[5]
+
+In 1505, Louis XII, having fallen ill, ordered that his daughter Claude and Francis be married immediately, but only through an assembly of nobles were the two engaged.[6] Claude was heir presumptive to the Duchy of Brittany through her mother, Anne of Brittany. Following Anne's death, the marriage took place on 18 May 1514.[7] On 1 January 1515, Louis died, and Francis inherited the throne. He was crowned King of France in the Cathedral of Reims on 25 January 1515, with Claude as his queen consort.[8]
+
+As Francis was receiving his education, ideas emerging from the Italian Renaissance were influential in France. Some of his tutors, such as François Desmoulins de Rochefort (his Latin instructor, who later during the reign of Francis was named Grand Aumônier de France) and Christophe de Longueil (a Brabantian humanist), were attracted by these new ways of thinking and attempted to influence Francis. His academic education had been in arithmetic, geography, grammar, history, reading, spelling, and writing and he became proficient in Hebrew, Italian, Latin and Spanish. Francis came to learn chivalry, dancing, and music, and he loved archery, falconry, horseback riding, hunting, jousting, real tennis and wrestling. He ended up reading philosophy and theology and he was fascinated with art, literature, poetry and science. His mother, who had a high admiration for Italian Renaissance art, passed this interest on to her son. Although Francis did not receive a humanist education, he was more influenced by humanism than any previous French king.
+
+By the time he ascended the throne in 1515, the Renaissance had arrived in France, and Francis became an enthusiastic patron of the arts. At the time of his accession, the royal palaces of France were ornamented with only a scattering of great paintings, and not a single sculpture, either ancient or modern. During Francis' reign, the magnificent art collection of the French kings, which can still be seen at the Louvre Palace, was begun.
+
+Francis patronized many great artists of his time, including Andrea del Sarto and Leonardo da Vinci; the latter of whom was persuaded to make France his home during his last years. While da Vinci painted very little during his years in France, he brought with him many of his greatest works, including the Mona Lisa (known in France as La Joconde), and these remained in France after his death. Other major artists to receive Francis' patronage included the goldsmith Benvenuto Cellini and the painters Rosso Fiorentino, Giulio Romano, and Primaticcio, all of whom were employed in decorating Francis' various palaces. He also invited the noted architect Sebastiano Serlio (1475–1554), who enjoyed a fruitful late career in France.[9] Francis also commissioned a number of agents in Italy to procure notable works of art and ship them to France.
+
+Francis was also renowned as a man of letters. When Francis comes up in a conversation among characters in Baldassare Castiglione's Book of the Courtier, it is as the great hope to bring culture to the war-obsessed French nation. Not only did Francis support a number of major writers of the period, he was a poet himself, if not one of particular abilities. Francis worked diligently at improving the royal library. He appointed the great French humanist Guillaume Budé as chief librarian and began to expand the collection. Francis employed agents in Italy to look for rare books and manuscripts, just as he had agents looking for art works. During his reign, the size of the library greatly increased. Not only did he expand the library, there is also evidence[citation needed] that he read the books he bought for it, a much rarer event in the royal annals. Francis set an important precedent by opening his library to scholars from around the world in order to facilitate the diffusion of knowledge.
+
+In 1537, Francis signed the Ordonnance de Montpellier, which decreed that his library be given a copy of every book to be sold in France.  Francis' older sister, Marguerite, Queen of Navarre, was also an accomplished writer who produced the classic collection of short stories known as the Heptameron.  Francis corresponded with the abbess and philosopher Claude de Bectoz, of whose letters he was so fond that he would carry them around and show them to the ladies of his court.[10]
+Together with his sister, he visited her in Tarascon.[11][failed verification]
+
+Francis poured vast amounts of money into new structures. He continued the work of his predecessors on the Château d'Amboise and also started renovations on the Château de Blois. Early in his reign, he began construction of the magnificent Château de Chambord, inspired by the architectural styles of the Italian renaissance, and perhaps even designed by Leonardo da Vinci. Francis rebuilt the Château du Louvre, transforming it from a medieval fortress into a building of Renaissance splendour. He financed the building of a new City Hall (the Hôtel de Ville) for Paris in order to have control over the building's design. He constructed the Château de Madrid in the Bois de Boulogne and rebuilt the Château de Saint-Germain-en-Laye. The largest of Francis' building projects was the reconstruction and expansion of the Château de Fontainebleau, which quickly became his favourite place of residence, as well as the residence of his official mistress, Anne, Duchess of Étampes. Each of Francis' projects was luxuriously decorated both inside and out. Fontainebleau, for instance, had a gushing fountain in its courtyard where quantities of wine were mixed with the water.
+
+Although the Italian Wars (1494–1559) came to dominate the reign of Francis I, the wars were not the sole focus of his policies.  Francis merely continued the incessant wars that his predecessors had started and that his successors on the throne of France would drag on after Francis' death.  Indeed, the Italian Wars had begun when Milan sent a plea to King Charles VIII of France for protection against the aggressive actions of the King of Naples.[12] Militarily and diplomatically, Francis' reign was a mixed bag of success and failure.  Francis tried and failed to become Holy Roman Emperor at the Imperial election of 1519.  However, there were also temporary victories, such as in the portion of the Italian Wars called the War of the League of Cambrai (1508–1516) and, more specifically, to the final stage of that war, which history refers to simply as "Francis' First Italian War" (1515–1516), when Francis routed the combined forces of the Papal States and the Old Swiss Confederacy at Marignano on 13–15 September 1515. This victory at Marignano allowed Francis to capture the Italian city-state of Milan. Later, in November 1521, during the Four Years' War (1521–1526) and facing the advancing Imperial forces of the Holy Roman Empire and open revolt within Milan, Francis was forced to abandon Milan, thus, cancelling the triumph at Marignano.
+
+Much of the military activity of Francis's reign was focused on his sworn enemy, the Holy Roman Emperor Charles V. Francis and Charles maintained an intense personal rivalry. Charles, in fact, brashly challenged Francis to single combat multiple times. In addition to the Holy Roman Empire, Charles personally ruled Spain, Austria, and a number of smaller possessions neighboring France. He was thus a constant threat to Francis' kingdom.
+
+Francis attempted to arrange an alliance with Henry VIII of England at the famous meeting at the Field of Cloth of Gold on 7 June 1520, but despite a lavish fortnight of diplomacy they failed to reach an agreement.[13]
+
+Francis suffered his most devastating defeat at the Battle of Pavia on 24 February 1525, during part of the continuing Italian Wars known as the Four Years' War. Francis was actually captured by the forces of Charles V after Cesare Hercolani was able to injure his horse, leading Francis to be captured by Diego Dávila, Alonso Pita da Veiga and Juan de Urbieta, from Guipúzcoa. For this reason, Hercolani was named "Victor of the battle of Pavia". Zuppa alla Pavese was supposedly invented on the spot to feed the captive king right after the battle.[14] There are allegations that Francis would have been killed by mistake by one of Charles' soldiers had Pedro de Valdivia —the future conqueror of Chile— not intervened.[15]
+
+Francis I was held captive in Madrid. In a letter to his mother he wrote, "Of all things, nothing remains to me but honour and life, which is safe." This line has come down in history famously as "All is lost save honour."[16] In the Treaty of Madrid, signed on 14 January 1526, Francis was forced to make major concessions to Charles V before he was freed on 17 March 1526. An ultimatum from Ottoman Sultan Suleiman to Charles V also played an important role in his release. Among the concessions that Francis I yielded to Charles V were the surrender of any claims to Naples and Milan in Italy.[17] Francis I was also forced to recognise the independence of the duchy of Burgundy, which had become part of France since the death of Charles, Duke of Burgundy on 5 January 1477,[18] during the reign of Louis XI.
+
+Furthermore, France was required to give up all claims to Flanders and the Artois.[17] Additionally, Francis I was allowed to return to France in exchange for his two sons, Francis and Henry, but once he was free he argued that his agreement with Charles was made under duress. He also claimed that the agreement was void because his sons were taken hostage with the implication that his word alone could not be trusted. Thus he firmly repudiated it.
+
+Francis persevered in his hatred of Charles V and desire to control Italy by conquest. The repudiation of the Treaty of Madrid led to the War of the League of Cognac of 1526–30. By the mid-1520s, Pope Clement VII wished to liberate Italy from foreign domination, especially that of Charles V, so to that end he negotiated with Venice to form the League of Cognac. Francis I willingly joined this anti-Imperial league on 22 May 1526.[19]
+
+After the league failed, Francis concluded a secret alliance with the Landgrave of Hesse on 27 January 1534. This was directed against Charles V on the pretext of assisting the Duke of Wurttemberg to regain his traditional seat, from which Charles had removed him in 1519. Francis also obtained the help of the Ottoman Empire and renewed the contest in Italy in the Italian War of 1536–1538 after the death of Francesco II Sforza, the ruler of Milan. This round of fighting, which had little result, was ended by the Truce of Nice. The agreement collapsed, however, which led to Francis' final attempt on Italy in the Italian War of 1542–1546. This time Francis managed to hold off the forces of Charles V and England's Henry VIII. Charles V was forced to sign the Treaty of Crépy because of his financial difficulties and conflicts with the Schmalkaldic League.
+
+Francis had been much aggrieved at the papal bull Aeterni regis: in June 1481 Portuguese rule over Africa and the Indies was confirmed by Pope Sixtus IV. Thirteen years later, on 7 June 1494, Portugal and the Crown of Castille signed the Treaty of Tordesillas under which the newly discovered lands would be divided between the two signatories. All this prompted King Francis to declare, "The sun shines for me as it does for others. I would very much like to see the clause of Adam’s will by which I should be denied my share of the world."[20]
+
+In order to counterbalance the power of the Habsburg Empire under Charles V, especially its control of large parts of the New World through the Crown of Spain, Francis I endeavoured to develop contacts with the New World and Asia. Fleets were sent to the Americas and the Far East, and close contacts were developed with the Ottoman Empire permitting the development of French Mediterranean trade as well as the establishment of a strategic military alliance.
+
+The port city now known as Le Havre was founded in 1517 during the early years of Francis' reign. The construction of a new port was urgently needed in order to replace the ancient harbours of Honfleur and Harfleur, whose utility had decreased due to silting. Le Havre was originally named Franciscopolis after the King who founded it, but this name did not survive into later reigns.
+
+In 1524, Francis assisted the citizens of Lyon in financing the expedition of Giovanni da Verrazzano to North America. On this expedition, Verrazzano visited the present site of New York City, naming it New Angoulême, and claimed Newfoundland for the French crown. Verrazzano's letter to Francis of 8 July 1524 is known as the Cèllere Codex.[21]
+
+In 1531, Bertrand d'Ornesan tried to establish a French trading post at Pernambuco, Brazil.[22]
+
+In 1534, Francis sent Jacques Cartier to explore the St. Lawrence River in Quebec to find "certain islands and lands where it is said there must be great quantities of gold and other riches".[23] In 1541, Francis sent Jean-François de Roberval to settle Canada and to provide for the spread of "the Holy Catholic faith."
+
+French trade with East Asia was initiated during the reign of Francis I with the help of shipowner Jean Ango. In July 1527, a French Norman trading ship from the city of Rouen is recorded by the Portuguese João de Barros as having arrived in the Indian city of Diu.[24] In 1529, Jean Parmentier, on board the Sacre and the Pensée, reached Sumatra.[24][25] Upon its return, the expedition triggered the development of the Dieppe maps, influencing the work of Dieppe cartographers such as Jean Rotz.[26]
+
+Under the reign of Francis I, France became the first country in Europe to establish formal relations with the Ottoman Empire and to set up instruction in the Arabic language under the guidance of Guillaume Postel at the Collège de France.[27]
+
+In a watershed moment in European diplomacy, Francis came to an understanding with the Ottoman Empire that developed into a Franco-Ottoman alliance. The alliance has been called "the first nonideological diplomatic alliance of its kind between a Christian and non-Christian empire".[28] It did, however, cause quite a scandal in the Christian world[29] and was designated "the impious alliance", or "the sacrilegious union of the [French] Lily and the [Ottoman] Crescent." Nevertheless, it endured for many years, since it served the objective interests of both parties.[30] The two powers colluded against Charles V, and in 1543 they even combined for a joint naval assault in the Siege of Nice.
+
+In 1533, Francis I sent colonel Pierre de Piton as ambassador to Morocco, initiating official France-Morocco relations.[31] In a letter to Francis I dated 13 August 1533, the Wattassid ruler of Fez, Ahmed ben Mohammed, welcomed French overtures and granted freedom of shipping and protection of French traders.
+
+Francis took several steps to eradicate the monopoly of Latin as the language of knowledge. In 1530, he declared French the national language of the kingdom, and that same year opened the Collège des trois langues, or Collège Royal, following the recommendation of humanist Guillaume Budé. Students at the Collège could study Greek, Hebrew and Aramaic, then Arabic under Guillaume Postel beginning in 1539.[32]
+
+In 1539, in his castle in Villers-Cotterêts,[33] Francis signed the important edict known as Ordinance of Villers-Cotterêts, which, among other reforms, made French the administrative language of the kingdom as a replacement for Latin. This same edict required priests to register births, marriages, and deaths, and to establish a registry office in every parish. This initiated the first records of vital statistics with filiations available in Europe.
+
+Divisions in Christianity in Western Europe during Francis' reign created lasting international rifts. Martin Luther's preaching and writing sparked the Protestant Reformation, which spread through much of Europe, including France.
+
+Initially, Francis was relatively tolerant of the new movement, under the influence of his beloved sister Marguerite de Navarre, who was genuinely attracted by Luther's theology. He even considered it politically useful, as it caused many German princes to turn against his enemy Charles V. In 1533 Francis even dared to suggest to Pope Clement VII that he convene a church council in which Catholic and Protestant rulers would have an equal vote in order to settle their differences – an offer rejected by both the Pope and Charles V. Beginning in 1523, however, Francis burned several heretics at the Place Maubert.[34]
+
+Francis' attitude towards Protestantism changed for the worse following the "Affair of the Placards", on the night of 17 October 1534, in which notices appeared on the streets of Paris and other major cities denouncing the Catholic mass. The most fervent Catholics were outraged by the notice's allegations. Francis himself came to view the movement as a plot against him and began to persecute its followers. Protestants were jailed and executed. In some areas whole villages were destroyed. In Paris, after 1540, Francis had heretics such as Etienne Dolet tortured and burned.[35] Printing was censored and leading Protestant reformers such as John Calvin were forced into exile. The persecutions soon numbered thousands of dead and tens of thousands of homeless.[36]
+
+Persecutions against Protestants were codified in the Edict of Fontainebleau (1540) issued by Francis. Major acts of violence continued, as when Francis ordered the execution of one of the historical pre-Lutheran groups, the Waldensians, at the Massacre of Mérindol in 1545.
+
+Francis died at the Château de Rambouillet on 31 March 1547, on his son and successor's 28th birthday. It is said that "he died complaining about the weight of a crown that he had first perceived as a gift from God".[37] He was interred with his first wife, Claude, Duchess of Brittany, in Saint Denis Basilica. He was succeeded by his son, Henry II.
+
+Francis' tomb and that of his wife and mother, along with the tombs of other French kings and members of the royal family, were desecrated on 20 October 1793 during the Reign of Terror at the height of the French Revolution.
+
+Francis' personal emblem was the salamander and his Latin motto was Nutrisco et extinguo ("I nourish [the good] and extinguish [the bad]").[citation needed]
+
+His long nose earned him the nickname François du Grand Nez ("Francis of the Big Nose"), he was also colloquially known as the "Grand Colas" or "Bonhomme Colas". For his personal involvement in battles, he was known as le Roi-Chevalier ("the Knight-King") or the le Roi-Guerrier ("the Warrior-King").[38]
+
+On 18 May 1514, Francis married his second cousin Claude, the daughter of King Louis XII of France and Duchess Anne of Brittany. The couple had seven children:
+
+On 7 July 1530, Francis I married his second wife Eleanor of Austria,[39] 
+a sister of the Emperor Charles V. The couple had no children. During his reign, Francis kept two official mistresses at court. The first was Françoise de Foix, Countess of Châteaubriant. In 1526, she was replaced by the blonde-haired, cultured Anne de Pisseleu d'Heilly, Duchess of Étampes who, with the death of Queen Claude two years earlier, wielded far more political power at court than her predecessor had done. Another of his earlier mistresses was allegedly Mary Boleyn, mistress of King Henry VIII and sister of Henry's future wife, Anne Boleyn.[40]
+
+The amorous exploits of Francis inspired the 1832 play by Fanny Kemble, Francis the First, and the 1832 play by Victor Hugo, Le Roi s'amuse ("The King's Amusement"), which featured the jester Triboulet, the inspiration for the 1851 opera Rigoletto by Giuseppe Verdi.
+
+Francis was first played in a George Méliès movie by an unknown actor in 1907, and has also been played by Claude Garry (1910), Aimé Simon-Girard (1937), Sacha Guitry (1937), Gérard Oury (1953), Jean Marais (1955), Pedro Armendáriz (1956), Claude Titre (1962), Bernard Pierre Donnadieu (1990). Timothy West (1998) and Emmanuel Leconte (2007– 2010).
+
+Francis was portrayed by Peter Gilmore in the comedy film Carry On Henry charting the fictitious two extra wives of Henry VIII (including Marie cousin of King Francis).
+
+Francis receives a mention in a minor story in Laurence Sterne's novel Tristram Shandy. The narrator claims that the king, wishing to win the favour of Switzerland, offers to make the country the godmother of his son. When, however, their choice of name conflicts, he declares war.
+
+He is also mentioned in Jean de la Brète's novel Reine – Mon oncle et mon curé, where the main character Reine de Lavalle idolises him after reading his biography, much to the dismay of the local priest.
+
+He often receives mentions in novels on the lives of either of the Boleyn sisters – Mary Boleyn (d. 1543) and her sister, Queen Anne Boleyn (executed 1536), both of whom were for a time educated at his court. Mary had, according to several accounts, been Francis' one-time mistress and Anne had been a favourite of his sister: the novels The Lady in the Tower, The Other Boleyn Girl, The Last Boleyn, Dear Heart, How Like You This? and Mademoiselle Boleyn feature Francis in their story. He appears in Hilary Mantel's Wolf Hall about Henry VIII's minister Thomas Cromwell and is often referred to in its sequel, Bring Up the Bodies.
+
+Francis is portrayed in Diane Haeger's novel Courtesan about Diane de Poitiers and Henri II.
+
+Francis appears as the patron of Benvenuto Cellini in the 1843 French novel L'Orfèvre du roi, ou Ascanio by Alexandre Dumas, père.
+
+Samuel Shellabarger's novel The King's Cavalier describes Francis the man, and the cultural and political circumstances of his reign, in some detail.
+
+He was a recurring character in the Showtime series The Tudors, opposite Jonathan Rhys Meyers as Henry VIII and Natalie Dormer as Anne Boleyn. Francis is played by French actor, Emmanuel Leconte.
+
+He and his court set the scene for Friedrich Schiller's ballad Der Handschuh (The Glove).
+
+Francis I (played by Timothy West) and Francis's son Henry II (played by Dougray Scott) are central figures in the 1998 movie Ever After, a retelling of the Cinderella story.  The plot includes Leonardo da Vinci (played by Patrick Godfrey) arriving at Francis's court with the Mona Lisa.
+
+He is played by Alfonso Bassave in the TVE series Carlos, rey emperador, opposite Álvaro Cervantes as Charles V.

en/2071.html.txt

@@ -0,0 +1,71 @@
+
+
+Archduke Franz Ferdinand Carl Ludwig Joseph Maria of Austria (18 December 1863 – 28 June 1914) was the heir presumptive to the throne of Austria-Hungary.[1] His assassination in Sarajevo is considered the most immediate cause of World War I.
+
+Franz Ferdinand was the eldest son of Archduke Karl Ludwig of Austria, the younger brother of Emperor Franz Joseph I. Following the suicide of Crown Prince Rudolf in 1889 and the death of Karl Ludwig in 1896, Franz Ferdinand became the heir presumptive to the Austro-Hungarian throne. His courtship of Sophie Chotek, a lady-in-waiting, caused conflict within the imperial household, and their morganatic marriage in 1900 was only allowed after he renounced his descendants' rights to the throne. Franz Ferdinand held significant influence over the military, and in 1913 he was appointed inspector general of the Austro-Hungarian armed forces.
+
+On 28 June 1914, Franz Ferdinand and his wife were assassinated in Sarajevo by the 19-year-old Gavrilo Princip, a member of Young Bosnia. Franz Ferdinand's assassination led to the July Crisis and precipitated Austria-Hungary's declaration of war against Serbia, which in turn triggered a series of events that eventually led to Austria-Hungary's allies and Serbia's allies declaring war on each other, starting World War I.[2][3][4]
+
+Franz Ferdinand was born in Graz, Austria, the eldest son of Archduke Karl Ludwig of Austria (the younger brother of Franz Joseph and Maximilian) and of his second wife, Princess Maria Annunciata of Bourbon-Two Sicilies. In 1875, when he was eleven years old, his cousin Francis V, Duke of Modena died, naming Franz Ferdinand his heir on condition that he add the name "Este" to his own. Franz Ferdinand thus became one of the wealthiest men in Austria.[citation needed]
+
+In 1889, Franz Ferdinand's life changed dramatically.  His cousin Crown Prince Rudolf committed suicide at his hunting lodge in Mayerling.[5] This left Franz Ferdinand's father, Karl Ludwig, as first in line to the throne. Karl Ludwig died of typhoid fever in 1896.[6] Henceforth, Franz Ferdinand was groomed to succeed to the throne.[citation needed]
+
+Despite this burden, he did manage to find time for travel and personal pursuits, such as his circumnavigation of the world between 1892 and 1893. After visiting India he spent time  hunting kangaroos and emus in Australia in 1893,[7] then travelled on to Nouméa, New Hebrides, Solomon Islands, New Guinea, Sarawak, Hong Kong and Japan.[8] After sailing across the Pacific on the RMS Empress of China from Yokohama to Vancouver[9] he crossed the United States and returned to Europe.
+
+The Archduke and his wife visited England in the autumn of 1913, spending a week with George V and Queen Mary at Windsor Castle before going to stay for another week with the Duke of Portland at Welbeck Abbey, Nottinghamshire, where they arrived on 22 November.  He attended a service at the local Catholic church in Worksop and the Duke and Archduke went game shooting on the Welbeck estate when, according to the Duke's memoirs, Men, Women and Things:
+
+One of the loaders fell down. This caused both barrels of the gun he was carrying to be discharged, the shot passing within a few feet of the archduke and myself.  I have often wondered whether the Great War might not have been averted, or at least postponed, had the archduke met his death there and not in Sarajevo the following year.[10]
+
+Franz Ferdinand had a fondness for trophy hunting that was excessive even by the standards of European nobility of this time.[11] In his diaries he kept track of an estimated 300,000 game kills, 5,000 of which were deer. About 100,000 trophies were on exhibit at his Bohemian castle at Konopiště[12][13] which he also stuffed with various antiquities, his other great passion.[14]
+
+Franz Ferdinand, like most males in the ruling Habsburg line, entered the Austro-Hungarian Army at a young age.  He was frequently and rapidly promoted, given the rank of lieutenant at age fourteen, captain at twenty-two, colonel at twenty-seven, and major general at thirty-one.[15] While never receiving formal staff training, he was considered eligible for command and at one point briefly led the primarily Hungarian 9th Hussar Regiment.[16] In 1898 he was given a commission "at the special disposition of His Majesty" to make inquiries into all aspects of the military services and military agencies were commanded to share their papers with him.[17]
+
+He also held honorary ranks in the Austro-Hungarian Navy, and received the rank of Admiral at the close of the Austro-Hungarian naval maneuvers in September 1902.[18]
+
+Franz Ferdinand exerted influence on the armed forces even when he did not hold a specific command through a military chancery that produced and received documents and papers on military affairs. This was headed by Alexander Brosch von Aarenau and eventually employed a staff of sixteen.[17] His authority was reinforced in 1907 when he secured the retirement of the Emperor's confidant Friedrich von Beck-Rzikowsky as Chief of the General Staff. Beck's successor, Franz Conrad von Hötzendorf, was personally selected by Franz Ferdinand.[19]
+
+Franz in 1913, as heir-presumptive to the elderly emperor, had been appointed inspector general of all the armed forces of Austria-Hungary (Generalinspektor der gesamten bewaffneten Macht), a position superior to that previously held by Archduke Albrecht and including presumed command in wartime.[20]
+
+In 1894 Franz Ferdinand met Countess Sophie Chotek, a lady-in-waiting to Archduchess Isabella, wife of Archduke Friedrich, Duke of Teschen.[21] Franz began to visit Archduke Friedrich's villa in Pressburg (now Bratislava), and in turn Sophie wrote to Franz Ferdinand during his convalescence from tuberculosis on the island of Lošinj in the Adriatic. They kept their relationship a secret,[22] until it was discovered by Isabella herself.
+
+To be eligible to marry a member of the imperial House of Habsburg, one had to be a member of one of the reigning or formerly reigning dynasties of Europe. The Choteks were not one of these families. Deeply in love, Franz Ferdinand refused to consider marrying anyone else. Finally, in 1899, Emperor Franz Joseph agreed to permit Franz Ferdinand to marry Sophie, on the condition that the marriage would be morganatic and that their descendants would not have succession rights to the throne.[5]  Sophie would not share her husband's rank, title, precedence, or privileges; as such, she would not normally appear in public beside him. She would not be allowed to ride in the royal carriage or sit in the royal box in theaters.[22]
+
+The wedding took place on 1 July 1900, at Reichstadt (now Zákupy) in Bohemia; Franz Joseph did not attend the affair, nor did any archduke including Franz Ferdinand's brothers.[5] The only members of the imperial family who were present were Franz Ferdinand's stepmother, Princess Maria Theresa of Braganza; and her two daughters. Upon the marriage, Sophie was given the title "Princess of Hohenberg" (Fürstin von Hohenberg) with the style "Her Serene Highness" (Ihre Durchlaucht).  In 1909, she was given the more senior title "Duchess of Hohenberg" (Herzogin von Hohenberg) with the style "Her Highness" (Ihre Hoheit). This raised her status considerably, but she still yielded precedence at court to all the archduchesses. Whenever a function required the couple to assemble with the other members of the imperial family, Sophie was forced to stand far down the line, separated from her husband.[22]
+
+Franz Ferdinand's children were:
+
+The German historian Michael Freund described Franz Ferdinand as "a man of uninspired energy, dark in appearance and emotion, who radiated an aura of strangeness and cast a shadow of violence and recklessness ... a true personality amidst the amiable inanity that characterized Austrian society at this time."[25] As his sometime admirer Karl Kraus put it, "he was not one who would greet you ... he felt no compulsion to reach out for the unexplored region which the Viennese call their heart."[26] His relations with Emperor Franz Joseph were tense; the emperor's personal servant recalled in his memoirs that "thunder and lightning always raged when they had their discussions."[27] The commentaries and orders which the heir to the throne wrote as margin notes to the documents of the Imperial central commission for architectural conservation (where he was Protector) reveal what can be described as "choleric conservatism."[28] The Italian historian Leo Valiani provided the following description.
+
+Francis Ferdinand was a prince of absolutist inclinations, but he had certain intellectual gifts and undoubted moral earnestness. One of his projects – though because of his impatient, suspicious, almost hysterical temperament, his commitment to it, and the methods by which he proposed to bring it about, often changed – was to consolidate the structure of the state and the authority and popularity of the Crown, on which he saw clearly that the fate of the dynasty depended, by abolishing, if not the dominance of the German Austrians, which he wished to maintain for military reasons, though he wanted to diminish it in the civil administration, certainly the far more burdensome sway of the Magyars over the Slav and Romanian nationalities which in 1848–49 had saved the dynasty in armed combat with the Hungarian revolution. Baron Margutti, Francis Joseph's aide-de-camp, was told by Francis Ferdinand in 1895 and – with a remarkable consistency in view of the changes that took place in the intervening years – again in 1913, that the introduction of the dual system in 1867 had been disastrous and that, when he ascended the throne, he intended to re-establish strong central government: this objective, he believed, could be attained only by the simultaneous granting of far-reaching administrative autonomy to all the nationalities of the monarchy. In a letter of February 1, 1913, to Berchtold, the Foreign Minister, in which he gave his reasons for not wanting war with Serbia, the Archduke said that "irredentism in our country ... will cease immediately if our Slavs are given a comfortable, fair and good life" instead of being trampled on (as they were being trampled on by the Hungarians). It must have been this which caused Berchtold, in a character sketch of Francis Ferdinand written ten years after his death, to say that, if he had succeeded to the throne, he would have tried to replace the dual system by a supranational federation.[29]
+
+Historians have disagreed on how to characterize the political philosophies of Franz Ferdinand, some attributing generally liberal views on the empire's nationalities while others have emphasized his dynastic centralism, Catholic conservatism, and tendency to clash with other leaders.[15] He advocated granting greater autonomy to ethnic groups within the Empire and addressing their grievances, especially the Czechs in Bohemia and the south Slavic peoples in Croatia and Bosnia, who had been left out of the Austro-Hungarian Compromise of 1867.[30] Yet his feelings towards the Hungarians were less generous, often described as antipathy. For example, in 1904 he wrote that "The Hungarians are all rabble, regardless of whether they are minister or duke, cardinal or burgher, peasant, hussar, domestic servant, or revolutionary", and he regarded even István Tisza as a revolutionary and "patented traitor".[31] He regarded Hungarian nationalism as a revolutionary threat to the Habsburg dynasty and reportedly became angry when officers of the 9th Hussars Regiment (which he commanded) spoke Hungarian in his presence – despite the fact that it was the official regimental language.[16] He further regarded the Hungarian branch of the Dual Monarchy's army, the Honvédség, as an unreliable and potentially threatening force within the empire, complaining at the Hungarians' failure to provide funds for the joint army[32] and opposing the formation of artillery units within the Hungarian forces.[33]
+
+He also advocated a cautious approach towards Serbia – repeatedly locking horns with Franz Conrad von Hötzendorf, Vienna's hard-line Chief of the General Staff, warning that harsh treatment of Serbia would bring Austria-Hungary into open conflict with Russia, to the ruin of both empires.
+
+He was disappointed when Austria-Hungary failed to act as a great power, such as during the Boxer Rebellion, in 1900. Other nations, including, in his description, "dwarf states like Belgium and Portugal",[19] had soldiers stationed in China, but Austria-Hungary did not. However, Austria-Hungary did participate in the Eight-Nation Alliance to suppress the Boxers, and sent soldiers as part of the "international relief force".
+
+Franz Ferdinand was a prominent and influential supporter of the Austro-Hungarian Navy in a time when sea power was not a priority in Austrian foreign policy and the Navy was relatively little known and supported by the public. After his assassination in 1914, the Navy honoured Franz Ferdinand and his wife with a lying in state aboard SMS Viribus Unitis.
+
+On Sunday, 28 June 1914, at about 10:45 am, Franz Ferdinand and his wife were assassinated in Sarajevo, the capital of the Austro-Hungarian province of Bosnia and Herzegovina. The perpetrator was 19-year-old Gavrilo Princip, a member of Young Bosnia and one of a group of assassins organized and armed by the Black Hand.[4]
+
+Earlier in the day, the couple had been attacked by Nedeljko Čabrinović, who had thrown a grenade at their car. However, the bomb detonated behind them, injuring the occupants in the following car. On arriving at the Governor's residence, Franz angrily shouted, "So this is how you welcome your guests – with bombs!"[34]
+
+After a short rest at the Governor's residence, the royal couple insisted on seeing all those who had been injured by the bomb at the local hospital. However, no one told the drivers that the itinerary had been changed. When the error was discovered, the drivers had to turn around. As the cars backed down the street and onto a side street, the line of cars stalled. At this same time, Princip was sitting at a cafe across the street. He instantly seized his opportunity and walked across the street and shot the royal couple.[34] He first shot Sophie in the abdomen and then shot Franz Ferdinand in the neck. Franz leaned over his crying wife. He was still alive when witnesses arrived to render aid.[4] His dying words to Sophie were, "Don't die darling, live for our children."[34] Princip's weapon was the pocket-sized FN Model 1910 pistol chambered for the .380 ACP cartridge provided him by Serbian Army Colonel and Black Hand member Dragutin Dimitrijević.[35] The archduke's aides attempted to undo his coat but realized they needed scissors to cut it open:  the outer lapel had been sewn to the inner front of the jacket for a smoother fit to improve the Archduke's appearance to the public.  Whether or not as a result of this obstacle, the Archduke's wound could not be attended to in time to save him, and he died within minutes. Sophie also died en route to the hospital.[36]
+
+A detailed account of the shooting can be found in Sarajevo by Joachim Remak:[37]
+
+One bullet pierced Franz Ferdinand's neck while the other pierced Sophie's abdomen. ... As the car was reversing (to go back to the Governor's residence because the entourage thought the Imperial couple were unhurt) a thin streak of blood shot from the Archduke's mouth onto Count Harrach's right cheek (he was standing on the car's running board). Harrach drew out a handkerchief to still the gushing blood. The Duchess, seeing this, called: "For Heaven's sake! What happened to you?" and sank from her seat, her face falling between her husband's knees.
+
+Harrach and Potoriek ... thought she had fainted ... only her husband seemed to have an instinct for what was happening. Turning to his wife despite the bullet in his neck, Franz Ferdinand pleaded: "Sopherl! Sopherl! Sterbe nicht! Bleibe am Leben für unsere Kinder! – Sophie dear! Don't die! Stay alive for our children!" Having said this, he seemed to sag down himself. His plumed hat ... fell off; many of its green feathers were found all over the car floor. Count Harrach seized the Archduke by the uniform collar to hold him up. He asked "Leiden Eure Kaiserliche Hoheit sehr? – Is Your Imperial Highness suffering very badly?"  "Es ist nichts. – It is nothing." said the Archduke in a weak but audible voice. He seemed to be losing consciousness during his last few minutes, but, his voice growing steadily weaker, he repeated the phrase perhaps six or seven times more.
+
+A rattle began to issue from his throat, which subsided as the car drew in front of the Konak bersibin (Town Hall).
+Despite several doctors' efforts, the Archduke died shortly after being carried into the building while his beloved wife was almost certainly dead from internal bleeding before the motorcade reached the Konak.
+
+The assassinations, along with the arms race, nationalism, imperialism, militarism, and the alliance system all contributed to the origins of World War I, which began a month after Franz Ferdinand's death, with Austria-Hungary's declaration of war against Serbia.[38] The assassination of Ferdinand is considered the most immediate cause of World War I.[39]
+
+Franz Ferdinand is interred with his wife Sophie in Artstetten Castle, Austria.
+
+Archduke Franz Ferdinand and his Castle of Artstetten were selected as a main motif for the Austrian 10 euro The Castle of Artstetten commemorative coin, minted on 13 October 2004. The reverse shows the entrance to the crypt of the Hohenberg family. There are two portraits below, showing Archduke Franz Ferdinand and his wife Sophie, Duchess of Hohenberg.[40]
+
+The Scottish band Franz Ferdinand named themselves after him.[41]
+

en/2072.html.txt

@@ -0,0 +1,71 @@
+
+
+Archduke Franz Ferdinand Carl Ludwig Joseph Maria of Austria (18 December 1863 – 28 June 1914) was the heir presumptive to the throne of Austria-Hungary.[1] His assassination in Sarajevo is considered the most immediate cause of World War I.
+
+Franz Ferdinand was the eldest son of Archduke Karl Ludwig of Austria, the younger brother of Emperor Franz Joseph I. Following the suicide of Crown Prince Rudolf in 1889 and the death of Karl Ludwig in 1896, Franz Ferdinand became the heir presumptive to the Austro-Hungarian throne. His courtship of Sophie Chotek, a lady-in-waiting, caused conflict within the imperial household, and their morganatic marriage in 1900 was only allowed after he renounced his descendants' rights to the throne. Franz Ferdinand held significant influence over the military, and in 1913 he was appointed inspector general of the Austro-Hungarian armed forces.
+
+On 28 June 1914, Franz Ferdinand and his wife were assassinated in Sarajevo by the 19-year-old Gavrilo Princip, a member of Young Bosnia. Franz Ferdinand's assassination led to the July Crisis and precipitated Austria-Hungary's declaration of war against Serbia, which in turn triggered a series of events that eventually led to Austria-Hungary's allies and Serbia's allies declaring war on each other, starting World War I.[2][3][4]
+
+Franz Ferdinand was born in Graz, Austria, the eldest son of Archduke Karl Ludwig of Austria (the younger brother of Franz Joseph and Maximilian) and of his second wife, Princess Maria Annunciata of Bourbon-Two Sicilies. In 1875, when he was eleven years old, his cousin Francis V, Duke of Modena died, naming Franz Ferdinand his heir on condition that he add the name "Este" to his own. Franz Ferdinand thus became one of the wealthiest men in Austria.[citation needed]
+
+In 1889, Franz Ferdinand's life changed dramatically.  His cousin Crown Prince Rudolf committed suicide at his hunting lodge in Mayerling.[5] This left Franz Ferdinand's father, Karl Ludwig, as first in line to the throne. Karl Ludwig died of typhoid fever in 1896.[6] Henceforth, Franz Ferdinand was groomed to succeed to the throne.[citation needed]
+
+Despite this burden, he did manage to find time for travel and personal pursuits, such as his circumnavigation of the world between 1892 and 1893. After visiting India he spent time  hunting kangaroos and emus in Australia in 1893,[7] then travelled on to Nouméa, New Hebrides, Solomon Islands, New Guinea, Sarawak, Hong Kong and Japan.[8] After sailing across the Pacific on the RMS Empress of China from Yokohama to Vancouver[9] he crossed the United States and returned to Europe.
+
+The Archduke and his wife visited England in the autumn of 1913, spending a week with George V and Queen Mary at Windsor Castle before going to stay for another week with the Duke of Portland at Welbeck Abbey, Nottinghamshire, where they arrived on 22 November.  He attended a service at the local Catholic church in Worksop and the Duke and Archduke went game shooting on the Welbeck estate when, according to the Duke's memoirs, Men, Women and Things:
+
+One of the loaders fell down. This caused both barrels of the gun he was carrying to be discharged, the shot passing within a few feet of the archduke and myself.  I have often wondered whether the Great War might not have been averted, or at least postponed, had the archduke met his death there and not in Sarajevo the following year.[10]
+
+Franz Ferdinand had a fondness for trophy hunting that was excessive even by the standards of European nobility of this time.[11] In his diaries he kept track of an estimated 300,000 game kills, 5,000 of which were deer. About 100,000 trophies were on exhibit at his Bohemian castle at Konopiště[12][13] which he also stuffed with various antiquities, his other great passion.[14]
+
+Franz Ferdinand, like most males in the ruling Habsburg line, entered the Austro-Hungarian Army at a young age.  He was frequently and rapidly promoted, given the rank of lieutenant at age fourteen, captain at twenty-two, colonel at twenty-seven, and major general at thirty-one.[15] While never receiving formal staff training, he was considered eligible for command and at one point briefly led the primarily Hungarian 9th Hussar Regiment.[16] In 1898 he was given a commission "at the special disposition of His Majesty" to make inquiries into all aspects of the military services and military agencies were commanded to share their papers with him.[17]
+
+He also held honorary ranks in the Austro-Hungarian Navy, and received the rank of Admiral at the close of the Austro-Hungarian naval maneuvers in September 1902.[18]
+
+Franz Ferdinand exerted influence on the armed forces even when he did not hold a specific command through a military chancery that produced and received documents and papers on military affairs. This was headed by Alexander Brosch von Aarenau and eventually employed a staff of sixteen.[17] His authority was reinforced in 1907 when he secured the retirement of the Emperor's confidant Friedrich von Beck-Rzikowsky as Chief of the General Staff. Beck's successor, Franz Conrad von Hötzendorf, was personally selected by Franz Ferdinand.[19]
+
+Franz in 1913, as heir-presumptive to the elderly emperor, had been appointed inspector general of all the armed forces of Austria-Hungary (Generalinspektor der gesamten bewaffneten Macht), a position superior to that previously held by Archduke Albrecht and including presumed command in wartime.[20]
+
+In 1894 Franz Ferdinand met Countess Sophie Chotek, a lady-in-waiting to Archduchess Isabella, wife of Archduke Friedrich, Duke of Teschen.[21] Franz began to visit Archduke Friedrich's villa in Pressburg (now Bratislava), and in turn Sophie wrote to Franz Ferdinand during his convalescence from tuberculosis on the island of Lošinj in the Adriatic. They kept their relationship a secret,[22] until it was discovered by Isabella herself.
+
+To be eligible to marry a member of the imperial House of Habsburg, one had to be a member of one of the reigning or formerly reigning dynasties of Europe. The Choteks were not one of these families. Deeply in love, Franz Ferdinand refused to consider marrying anyone else. Finally, in 1899, Emperor Franz Joseph agreed to permit Franz Ferdinand to marry Sophie, on the condition that the marriage would be morganatic and that their descendants would not have succession rights to the throne.[5]  Sophie would not share her husband's rank, title, precedence, or privileges; as such, she would not normally appear in public beside him. She would not be allowed to ride in the royal carriage or sit in the royal box in theaters.[22]
+
+The wedding took place on 1 July 1900, at Reichstadt (now Zákupy) in Bohemia; Franz Joseph did not attend the affair, nor did any archduke including Franz Ferdinand's brothers.[5] The only members of the imperial family who were present were Franz Ferdinand's stepmother, Princess Maria Theresa of Braganza; and her two daughters. Upon the marriage, Sophie was given the title "Princess of Hohenberg" (Fürstin von Hohenberg) with the style "Her Serene Highness" (Ihre Durchlaucht).  In 1909, she was given the more senior title "Duchess of Hohenberg" (Herzogin von Hohenberg) with the style "Her Highness" (Ihre Hoheit). This raised her status considerably, but she still yielded precedence at court to all the archduchesses. Whenever a function required the couple to assemble with the other members of the imperial family, Sophie was forced to stand far down the line, separated from her husband.[22]
+
+Franz Ferdinand's children were:
+
+The German historian Michael Freund described Franz Ferdinand as "a man of uninspired energy, dark in appearance and emotion, who radiated an aura of strangeness and cast a shadow of violence and recklessness ... a true personality amidst the amiable inanity that characterized Austrian society at this time."[25] As his sometime admirer Karl Kraus put it, "he was not one who would greet you ... he felt no compulsion to reach out for the unexplored region which the Viennese call their heart."[26] His relations with Emperor Franz Joseph were tense; the emperor's personal servant recalled in his memoirs that "thunder and lightning always raged when they had their discussions."[27] The commentaries and orders which the heir to the throne wrote as margin notes to the documents of the Imperial central commission for architectural conservation (where he was Protector) reveal what can be described as "choleric conservatism."[28] The Italian historian Leo Valiani provided the following description.
+
+Francis Ferdinand was a prince of absolutist inclinations, but he had certain intellectual gifts and undoubted moral earnestness. One of his projects – though because of his impatient, suspicious, almost hysterical temperament, his commitment to it, and the methods by which he proposed to bring it about, often changed – was to consolidate the structure of the state and the authority and popularity of the Crown, on which he saw clearly that the fate of the dynasty depended, by abolishing, if not the dominance of the German Austrians, which he wished to maintain for military reasons, though he wanted to diminish it in the civil administration, certainly the far more burdensome sway of the Magyars over the Slav and Romanian nationalities which in 1848–49 had saved the dynasty in armed combat with the Hungarian revolution. Baron Margutti, Francis Joseph's aide-de-camp, was told by Francis Ferdinand in 1895 and – with a remarkable consistency in view of the changes that took place in the intervening years – again in 1913, that the introduction of the dual system in 1867 had been disastrous and that, when he ascended the throne, he intended to re-establish strong central government: this objective, he believed, could be attained only by the simultaneous granting of far-reaching administrative autonomy to all the nationalities of the monarchy. In a letter of February 1, 1913, to Berchtold, the Foreign Minister, in which he gave his reasons for not wanting war with Serbia, the Archduke said that "irredentism in our country ... will cease immediately if our Slavs are given a comfortable, fair and good life" instead of being trampled on (as they were being trampled on by the Hungarians). It must have been this which caused Berchtold, in a character sketch of Francis Ferdinand written ten years after his death, to say that, if he had succeeded to the throne, he would have tried to replace the dual system by a supranational federation.[29]
+
+Historians have disagreed on how to characterize the political philosophies of Franz Ferdinand, some attributing generally liberal views on the empire's nationalities while others have emphasized his dynastic centralism, Catholic conservatism, and tendency to clash with other leaders.[15] He advocated granting greater autonomy to ethnic groups within the Empire and addressing their grievances, especially the Czechs in Bohemia and the south Slavic peoples in Croatia and Bosnia, who had been left out of the Austro-Hungarian Compromise of 1867.[30] Yet his feelings towards the Hungarians were less generous, often described as antipathy. For example, in 1904 he wrote that "The Hungarians are all rabble, regardless of whether they are minister or duke, cardinal or burgher, peasant, hussar, domestic servant, or revolutionary", and he regarded even István Tisza as a revolutionary and "patented traitor".[31] He regarded Hungarian nationalism as a revolutionary threat to the Habsburg dynasty and reportedly became angry when officers of the 9th Hussars Regiment (which he commanded) spoke Hungarian in his presence – despite the fact that it was the official regimental language.[16] He further regarded the Hungarian branch of the Dual Monarchy's army, the Honvédség, as an unreliable and potentially threatening force within the empire, complaining at the Hungarians' failure to provide funds for the joint army[32] and opposing the formation of artillery units within the Hungarian forces.[33]
+
+He also advocated a cautious approach towards Serbia – repeatedly locking horns with Franz Conrad von Hötzendorf, Vienna's hard-line Chief of the General Staff, warning that harsh treatment of Serbia would bring Austria-Hungary into open conflict with Russia, to the ruin of both empires.
+
+He was disappointed when Austria-Hungary failed to act as a great power, such as during the Boxer Rebellion, in 1900. Other nations, including, in his description, "dwarf states like Belgium and Portugal",[19] had soldiers stationed in China, but Austria-Hungary did not. However, Austria-Hungary did participate in the Eight-Nation Alliance to suppress the Boxers, and sent soldiers as part of the "international relief force".
+
+Franz Ferdinand was a prominent and influential supporter of the Austro-Hungarian Navy in a time when sea power was not a priority in Austrian foreign policy and the Navy was relatively little known and supported by the public. After his assassination in 1914, the Navy honoured Franz Ferdinand and his wife with a lying in state aboard SMS Viribus Unitis.
+
+On Sunday, 28 June 1914, at about 10:45 am, Franz Ferdinand and his wife were assassinated in Sarajevo, the capital of the Austro-Hungarian province of Bosnia and Herzegovina. The perpetrator was 19-year-old Gavrilo Princip, a member of Young Bosnia and one of a group of assassins organized and armed by the Black Hand.[4]
+
+Earlier in the day, the couple had been attacked by Nedeljko Čabrinović, who had thrown a grenade at their car. However, the bomb detonated behind them, injuring the occupants in the following car. On arriving at the Governor's residence, Franz angrily shouted, "So this is how you welcome your guests – with bombs!"[34]
+
+After a short rest at the Governor's residence, the royal couple insisted on seeing all those who had been injured by the bomb at the local hospital. However, no one told the drivers that the itinerary had been changed. When the error was discovered, the drivers had to turn around. As the cars backed down the street and onto a side street, the line of cars stalled. At this same time, Princip was sitting at a cafe across the street. He instantly seized his opportunity and walked across the street and shot the royal couple.[34] He first shot Sophie in the abdomen and then shot Franz Ferdinand in the neck. Franz leaned over his crying wife. He was still alive when witnesses arrived to render aid.[4] His dying words to Sophie were, "Don't die darling, live for our children."[34] Princip's weapon was the pocket-sized FN Model 1910 pistol chambered for the .380 ACP cartridge provided him by Serbian Army Colonel and Black Hand member Dragutin Dimitrijević.[35] The archduke's aides attempted to undo his coat but realized they needed scissors to cut it open:  the outer lapel had been sewn to the inner front of the jacket for a smoother fit to improve the Archduke's appearance to the public.  Whether or not as a result of this obstacle, the Archduke's wound could not be attended to in time to save him, and he died within minutes. Sophie also died en route to the hospital.[36]
+
+A detailed account of the shooting can be found in Sarajevo by Joachim Remak:[37]
+
+One bullet pierced Franz Ferdinand's neck while the other pierced Sophie's abdomen. ... As the car was reversing (to go back to the Governor's residence because the entourage thought the Imperial couple were unhurt) a thin streak of blood shot from the Archduke's mouth onto Count Harrach's right cheek (he was standing on the car's running board). Harrach drew out a handkerchief to still the gushing blood. The Duchess, seeing this, called: "For Heaven's sake! What happened to you?" and sank from her seat, her face falling between her husband's knees.
+
+Harrach and Potoriek ... thought she had fainted ... only her husband seemed to have an instinct for what was happening. Turning to his wife despite the bullet in his neck, Franz Ferdinand pleaded: "Sopherl! Sopherl! Sterbe nicht! Bleibe am Leben für unsere Kinder! – Sophie dear! Don't die! Stay alive for our children!" Having said this, he seemed to sag down himself. His plumed hat ... fell off; many of its green feathers were found all over the car floor. Count Harrach seized the Archduke by the uniform collar to hold him up. He asked "Leiden Eure Kaiserliche Hoheit sehr? – Is Your Imperial Highness suffering very badly?"  "Es ist nichts. – It is nothing." said the Archduke in a weak but audible voice. He seemed to be losing consciousness during his last few minutes, but, his voice growing steadily weaker, he repeated the phrase perhaps six or seven times more.
+
+A rattle began to issue from his throat, which subsided as the car drew in front of the Konak bersibin (Town Hall).
+Despite several doctors' efforts, the Archduke died shortly after being carried into the building while his beloved wife was almost certainly dead from internal bleeding before the motorcade reached the Konak.
+
+The assassinations, along with the arms race, nationalism, imperialism, militarism, and the alliance system all contributed to the origins of World War I, which began a month after Franz Ferdinand's death, with Austria-Hungary's declaration of war against Serbia.[38] The assassination of Ferdinand is considered the most immediate cause of World War I.[39]
+
+Franz Ferdinand is interred with his wife Sophie in Artstetten Castle, Austria.
+
+Archduke Franz Ferdinand and his Castle of Artstetten were selected as a main motif for the Austrian 10 euro The Castle of Artstetten commemorative coin, minted on 13 October 2004. The reverse shows the entrance to the crypt of the Hohenberg family. There are two portraits below, showing Archduke Franz Ferdinand and his wife Sophie, Duchess of Hohenberg.[40]
+
+The Scottish band Franz Ferdinand named themselves after him.[41]
+

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+
+
+Francis I (French: François Ier; Middle French: Francoys; 12 September 1494 – 31 March 1547) was King of France from 1515 until his death in 1547. He was the son of Charles, Count of Angoulême, and Louise of Savoy. He succeeded his first cousin once removed and father-in-law Louis XII, who died without a son.
+
+A prodigious patron of the arts, he initiated the French Renaissance by attracting many Italian artists to work for him, including Leonardo da Vinci, who brought the Mona Lisa with him, which Francis had acquired. Francis' reign saw important cultural changes with the rise of absolute monarchy in France, the spread of humanism and Protestantism, and the beginning of French exploration of the New World. Jacques Cartier and others claimed lands in the Americas for France and paved the way for the expansion of the first French colonial empire.
+
+For his role in the development and promotion of a standardized French language, he became known as le Père et Restaurateur des Lettres (the 'Father and Restorer of Letters').[1] He was also known as François du Grand Nez ('Francis of the Large Nose'), the Grand Colas, and the Roi-Chevalier (the 'Knight-King')[1] for his personal involvement in the wars against his great rival Emperor Charles V, who was also King of Spain.
+
+Following the policy of his predecessors, Francis continued the Italian Wars. The succession of Charles V to the Burgundian Netherlands, the throne of Spain, and his subsequent election as Holy Roman Emperor meant that France was geographically encircled by the Habsburg monarchy. In his struggle against Imperial hegemony, he sought the support of Henry VIII of England at the Field of the Cloth of Gold.[2] When this was unsuccessful, he formed a Franco-Ottoman alliance with the Muslim sultan Suleiman the Magnificent, a controversial move for a Christian king at the time.[3]
+
+Francis of Orléans was born on 12 September 1494 at the Château de Cognac in the town of Cognac,[1] which at that time lay in the province of Saintonge, a part of the Duchy of Aquitaine.  Today the town lies in the department of Charente.
+
+Francis was the only son of Charles of Orléans, Count of Angoulême, and Louise of Savoy and a great-great-grandson of King Charles V of France.[4] His family was not expected to inherit the throne, as his third cousin King Charles VIII was still young at the time of his birth, as was his father's cousin the Duke of Orléans, later King Louis XII. However, Charles VIII died childless in 1498 and was succeeded by Louis XII, who himself had no male heir.[5] The Salic Law prevented women from inheriting the throne.  Therefore, the four-year-old Francis (who was already Count of Angoulême after the death of his own father two years earlier) became the heir presumptive to the throne of France in 1498 and was vested with the title of Duke of Valois.[5]
+
+In 1505, Louis XII, having fallen ill, ordered that his daughter Claude and Francis be married immediately, but only through an assembly of nobles were the two engaged.[6] Claude was heir presumptive to the Duchy of Brittany through her mother, Anne of Brittany. Following Anne's death, the marriage took place on 18 May 1514.[7] On 1 January 1515, Louis died, and Francis inherited the throne. He was crowned King of France in the Cathedral of Reims on 25 January 1515, with Claude as his queen consort.[8]
+
+As Francis was receiving his education, ideas emerging from the Italian Renaissance were influential in France. Some of his tutors, such as François Desmoulins de Rochefort (his Latin instructor, who later during the reign of Francis was named Grand Aumônier de France) and Christophe de Longueil (a Brabantian humanist), were attracted by these new ways of thinking and attempted to influence Francis. His academic education had been in arithmetic, geography, grammar, history, reading, spelling, and writing and he became proficient in Hebrew, Italian, Latin and Spanish. Francis came to learn chivalry, dancing, and music, and he loved archery, falconry, horseback riding, hunting, jousting, real tennis and wrestling. He ended up reading philosophy and theology and he was fascinated with art, literature, poetry and science. His mother, who had a high admiration for Italian Renaissance art, passed this interest on to her son. Although Francis did not receive a humanist education, he was more influenced by humanism than any previous French king.
+
+By the time he ascended the throne in 1515, the Renaissance had arrived in France, and Francis became an enthusiastic patron of the arts. At the time of his accession, the royal palaces of France were ornamented with only a scattering of great paintings, and not a single sculpture, either ancient or modern. During Francis' reign, the magnificent art collection of the French kings, which can still be seen at the Louvre Palace, was begun.
+
+Francis patronized many great artists of his time, including Andrea del Sarto and Leonardo da Vinci; the latter of whom was persuaded to make France his home during his last years. While da Vinci painted very little during his years in France, he brought with him many of his greatest works, including the Mona Lisa (known in France as La Joconde), and these remained in France after his death. Other major artists to receive Francis' patronage included the goldsmith Benvenuto Cellini and the painters Rosso Fiorentino, Giulio Romano, and Primaticcio, all of whom were employed in decorating Francis' various palaces. He also invited the noted architect Sebastiano Serlio (1475–1554), who enjoyed a fruitful late career in France.[9] Francis also commissioned a number of agents in Italy to procure notable works of art and ship them to France.
+
+Francis was also renowned as a man of letters. When Francis comes up in a conversation among characters in Baldassare Castiglione's Book of the Courtier, it is as the great hope to bring culture to the war-obsessed French nation. Not only did Francis support a number of major writers of the period, he was a poet himself, if not one of particular abilities. Francis worked diligently at improving the royal library. He appointed the great French humanist Guillaume Budé as chief librarian and began to expand the collection. Francis employed agents in Italy to look for rare books and manuscripts, just as he had agents looking for art works. During his reign, the size of the library greatly increased. Not only did he expand the library, there is also evidence[citation needed] that he read the books he bought for it, a much rarer event in the royal annals. Francis set an important precedent by opening his library to scholars from around the world in order to facilitate the diffusion of knowledge.
+
+In 1537, Francis signed the Ordonnance de Montpellier, which decreed that his library be given a copy of every book to be sold in France.  Francis' older sister, Marguerite, Queen of Navarre, was also an accomplished writer who produced the classic collection of short stories known as the Heptameron.  Francis corresponded with the abbess and philosopher Claude de Bectoz, of whose letters he was so fond that he would carry them around and show them to the ladies of his court.[10]
+Together with his sister, he visited her in Tarascon.[11][failed verification]
+
+Francis poured vast amounts of money into new structures. He continued the work of his predecessors on the Château d'Amboise and also started renovations on the Château de Blois. Early in his reign, he began construction of the magnificent Château de Chambord, inspired by the architectural styles of the Italian renaissance, and perhaps even designed by Leonardo da Vinci. Francis rebuilt the Château du Louvre, transforming it from a medieval fortress into a building of Renaissance splendour. He financed the building of a new City Hall (the Hôtel de Ville) for Paris in order to have control over the building's design. He constructed the Château de Madrid in the Bois de Boulogne and rebuilt the Château de Saint-Germain-en-Laye. The largest of Francis' building projects was the reconstruction and expansion of the Château de Fontainebleau, which quickly became his favourite place of residence, as well as the residence of his official mistress, Anne, Duchess of Étampes. Each of Francis' projects was luxuriously decorated both inside and out. Fontainebleau, for instance, had a gushing fountain in its courtyard where quantities of wine were mixed with the water.
+
+Although the Italian Wars (1494–1559) came to dominate the reign of Francis I, the wars were not the sole focus of his policies.  Francis merely continued the incessant wars that his predecessors had started and that his successors on the throne of France would drag on after Francis' death.  Indeed, the Italian Wars had begun when Milan sent a plea to King Charles VIII of France for protection against the aggressive actions of the King of Naples.[12] Militarily and diplomatically, Francis' reign was a mixed bag of success and failure.  Francis tried and failed to become Holy Roman Emperor at the Imperial election of 1519.  However, there were also temporary victories, such as in the portion of the Italian Wars called the War of the League of Cambrai (1508–1516) and, more specifically, to the final stage of that war, which history refers to simply as "Francis' First Italian War" (1515–1516), when Francis routed the combined forces of the Papal States and the Old Swiss Confederacy at Marignano on 13–15 September 1515. This victory at Marignano allowed Francis to capture the Italian city-state of Milan. Later, in November 1521, during the Four Years' War (1521–1526) and facing the advancing Imperial forces of the Holy Roman Empire and open revolt within Milan, Francis was forced to abandon Milan, thus, cancelling the triumph at Marignano.
+
+Much of the military activity of Francis's reign was focused on his sworn enemy, the Holy Roman Emperor Charles V. Francis and Charles maintained an intense personal rivalry. Charles, in fact, brashly challenged Francis to single combat multiple times. In addition to the Holy Roman Empire, Charles personally ruled Spain, Austria, and a number of smaller possessions neighboring France. He was thus a constant threat to Francis' kingdom.
+
+Francis attempted to arrange an alliance with Henry VIII of England at the famous meeting at the Field of Cloth of Gold on 7 June 1520, but despite a lavish fortnight of diplomacy they failed to reach an agreement.[13]
+
+Francis suffered his most devastating defeat at the Battle of Pavia on 24 February 1525, during part of the continuing Italian Wars known as the Four Years' War. Francis was actually captured by the forces of Charles V after Cesare Hercolani was able to injure his horse, leading Francis to be captured by Diego Dávila, Alonso Pita da Veiga and Juan de Urbieta, from Guipúzcoa. For this reason, Hercolani was named "Victor of the battle of Pavia". Zuppa alla Pavese was supposedly invented on the spot to feed the captive king right after the battle.[14] There are allegations that Francis would have been killed by mistake by one of Charles' soldiers had Pedro de Valdivia —the future conqueror of Chile— not intervened.[15]
+
+Francis I was held captive in Madrid. In a letter to his mother he wrote, "Of all things, nothing remains to me but honour and life, which is safe." This line has come down in history famously as "All is lost save honour."[16] In the Treaty of Madrid, signed on 14 January 1526, Francis was forced to make major concessions to Charles V before he was freed on 17 March 1526. An ultimatum from Ottoman Sultan Suleiman to Charles V also played an important role in his release. Among the concessions that Francis I yielded to Charles V were the surrender of any claims to Naples and Milan in Italy.[17] Francis I was also forced to recognise the independence of the duchy of Burgundy, which had become part of France since the death of Charles, Duke of Burgundy on 5 January 1477,[18] during the reign of Louis XI.
+
+Furthermore, France was required to give up all claims to Flanders and the Artois.[17] Additionally, Francis I was allowed to return to France in exchange for his two sons, Francis and Henry, but once he was free he argued that his agreement with Charles was made under duress. He also claimed that the agreement was void because his sons were taken hostage with the implication that his word alone could not be trusted. Thus he firmly repudiated it.
+
+Francis persevered in his hatred of Charles V and desire to control Italy by conquest. The repudiation of the Treaty of Madrid led to the War of the League of Cognac of 1526–30. By the mid-1520s, Pope Clement VII wished to liberate Italy from foreign domination, especially that of Charles V, so to that end he negotiated with Venice to form the League of Cognac. Francis I willingly joined this anti-Imperial league on 22 May 1526.[19]
+
+After the league failed, Francis concluded a secret alliance with the Landgrave of Hesse on 27 January 1534. This was directed against Charles V on the pretext of assisting the Duke of Wurttemberg to regain his traditional seat, from which Charles had removed him in 1519. Francis also obtained the help of the Ottoman Empire and renewed the contest in Italy in the Italian War of 1536–1538 after the death of Francesco II Sforza, the ruler of Milan. This round of fighting, which had little result, was ended by the Truce of Nice. The agreement collapsed, however, which led to Francis' final attempt on Italy in the Italian War of 1542–1546. This time Francis managed to hold off the forces of Charles V and England's Henry VIII. Charles V was forced to sign the Treaty of Crépy because of his financial difficulties and conflicts with the Schmalkaldic League.
+
+Francis had been much aggrieved at the papal bull Aeterni regis: in June 1481 Portuguese rule over Africa and the Indies was confirmed by Pope Sixtus IV. Thirteen years later, on 7 June 1494, Portugal and the Crown of Castille signed the Treaty of Tordesillas under which the newly discovered lands would be divided between the two signatories. All this prompted King Francis to declare, "The sun shines for me as it does for others. I would very much like to see the clause of Adam’s will by which I should be denied my share of the world."[20]
+
+In order to counterbalance the power of the Habsburg Empire under Charles V, especially its control of large parts of the New World through the Crown of Spain, Francis I endeavoured to develop contacts with the New World and Asia. Fleets were sent to the Americas and the Far East, and close contacts were developed with the Ottoman Empire permitting the development of French Mediterranean trade as well as the establishment of a strategic military alliance.
+
+The port city now known as Le Havre was founded in 1517 during the early years of Francis' reign. The construction of a new port was urgently needed in order to replace the ancient harbours of Honfleur and Harfleur, whose utility had decreased due to silting. Le Havre was originally named Franciscopolis after the King who founded it, but this name did not survive into later reigns.
+
+In 1524, Francis assisted the citizens of Lyon in financing the expedition of Giovanni da Verrazzano to North America. On this expedition, Verrazzano visited the present site of New York City, naming it New Angoulême, and claimed Newfoundland for the French crown. Verrazzano's letter to Francis of 8 July 1524 is known as the Cèllere Codex.[21]
+
+In 1531, Bertrand d'Ornesan tried to establish a French trading post at Pernambuco, Brazil.[22]
+
+In 1534, Francis sent Jacques Cartier to explore the St. Lawrence River in Quebec to find "certain islands and lands where it is said there must be great quantities of gold and other riches".[23] In 1541, Francis sent Jean-François de Roberval to settle Canada and to provide for the spread of "the Holy Catholic faith."
+
+French trade with East Asia was initiated during the reign of Francis I with the help of shipowner Jean Ango. In July 1527, a French Norman trading ship from the city of Rouen is recorded by the Portuguese João de Barros as having arrived in the Indian city of Diu.[24] In 1529, Jean Parmentier, on board the Sacre and the Pensée, reached Sumatra.[24][25] Upon its return, the expedition triggered the development of the Dieppe maps, influencing the work of Dieppe cartographers such as Jean Rotz.[26]
+
+Under the reign of Francis I, France became the first country in Europe to establish formal relations with the Ottoman Empire and to set up instruction in the Arabic language under the guidance of Guillaume Postel at the Collège de France.[27]
+
+In a watershed moment in European diplomacy, Francis came to an understanding with the Ottoman Empire that developed into a Franco-Ottoman alliance. The alliance has been called "the first nonideological diplomatic alliance of its kind between a Christian and non-Christian empire".[28] It did, however, cause quite a scandal in the Christian world[29] and was designated "the impious alliance", or "the sacrilegious union of the [French] Lily and the [Ottoman] Crescent." Nevertheless, it endured for many years, since it served the objective interests of both parties.[30] The two powers colluded against Charles V, and in 1543 they even combined for a joint naval assault in the Siege of Nice.
+
+In 1533, Francis I sent colonel Pierre de Piton as ambassador to Morocco, initiating official France-Morocco relations.[31] In a letter to Francis I dated 13 August 1533, the Wattassid ruler of Fez, Ahmed ben Mohammed, welcomed French overtures and granted freedom of shipping and protection of French traders.
+
+Francis took several steps to eradicate the monopoly of Latin as the language of knowledge. In 1530, he declared French the national language of the kingdom, and that same year opened the Collège des trois langues, or Collège Royal, following the recommendation of humanist Guillaume Budé. Students at the Collège could study Greek, Hebrew and Aramaic, then Arabic under Guillaume Postel beginning in 1539.[32]
+
+In 1539, in his castle in Villers-Cotterêts,[33] Francis signed the important edict known as Ordinance of Villers-Cotterêts, which, among other reforms, made French the administrative language of the kingdom as a replacement for Latin. This same edict required priests to register births, marriages, and deaths, and to establish a registry office in every parish. This initiated the first records of vital statistics with filiations available in Europe.
+
+Divisions in Christianity in Western Europe during Francis' reign created lasting international rifts. Martin Luther's preaching and writing sparked the Protestant Reformation, which spread through much of Europe, including France.
+
+Initially, Francis was relatively tolerant of the new movement, under the influence of his beloved sister Marguerite de Navarre, who was genuinely attracted by Luther's theology. He even considered it politically useful, as it caused many German princes to turn against his enemy Charles V. In 1533 Francis even dared to suggest to Pope Clement VII that he convene a church council in which Catholic and Protestant rulers would have an equal vote in order to settle their differences – an offer rejected by both the Pope and Charles V. Beginning in 1523, however, Francis burned several heretics at the Place Maubert.[34]
+
+Francis' attitude towards Protestantism changed for the worse following the "Affair of the Placards", on the night of 17 October 1534, in which notices appeared on the streets of Paris and other major cities denouncing the Catholic mass. The most fervent Catholics were outraged by the notice's allegations. Francis himself came to view the movement as a plot against him and began to persecute its followers. Protestants were jailed and executed. In some areas whole villages were destroyed. In Paris, after 1540, Francis had heretics such as Etienne Dolet tortured and burned.[35] Printing was censored and leading Protestant reformers such as John Calvin were forced into exile. The persecutions soon numbered thousands of dead and tens of thousands of homeless.[36]
+
+Persecutions against Protestants were codified in the Edict of Fontainebleau (1540) issued by Francis. Major acts of violence continued, as when Francis ordered the execution of one of the historical pre-Lutheran groups, the Waldensians, at the Massacre of Mérindol in 1545.
+
+Francis died at the Château de Rambouillet on 31 March 1547, on his son and successor's 28th birthday. It is said that "he died complaining about the weight of a crown that he had first perceived as a gift from God".[37] He was interred with his first wife, Claude, Duchess of Brittany, in Saint Denis Basilica. He was succeeded by his son, Henry II.
+
+Francis' tomb and that of his wife and mother, along with the tombs of other French kings and members of the royal family, were desecrated on 20 October 1793 during the Reign of Terror at the height of the French Revolution.
+
+Francis' personal emblem was the salamander and his Latin motto was Nutrisco et extinguo ("I nourish [the good] and extinguish [the bad]").[citation needed]
+
+His long nose earned him the nickname François du Grand Nez ("Francis of the Big Nose"), he was also colloquially known as the "Grand Colas" or "Bonhomme Colas". For his personal involvement in battles, he was known as le Roi-Chevalier ("the Knight-King") or the le Roi-Guerrier ("the Warrior-King").[38]
+
+On 18 May 1514, Francis married his second cousin Claude, the daughter of King Louis XII of France and Duchess Anne of Brittany. The couple had seven children:
+
+On 7 July 1530, Francis I married his second wife Eleanor of Austria,[39] 
+a sister of the Emperor Charles V. The couple had no children. During his reign, Francis kept two official mistresses at court. The first was Françoise de Foix, Countess of Châteaubriant. In 1526, she was replaced by the blonde-haired, cultured Anne de Pisseleu d'Heilly, Duchess of Étampes who, with the death of Queen Claude two years earlier, wielded far more political power at court than her predecessor had done. Another of his earlier mistresses was allegedly Mary Boleyn, mistress of King Henry VIII and sister of Henry's future wife, Anne Boleyn.[40]
+
+The amorous exploits of Francis inspired the 1832 play by Fanny Kemble, Francis the First, and the 1832 play by Victor Hugo, Le Roi s'amuse ("The King's Amusement"), which featured the jester Triboulet, the inspiration for the 1851 opera Rigoletto by Giuseppe Verdi.
+
+Francis was first played in a George Méliès movie by an unknown actor in 1907, and has also been played by Claude Garry (1910), Aimé Simon-Girard (1937), Sacha Guitry (1937), Gérard Oury (1953), Jean Marais (1955), Pedro Armendáriz (1956), Claude Titre (1962), Bernard Pierre Donnadieu (1990). Timothy West (1998) and Emmanuel Leconte (2007– 2010).
+
+Francis was portrayed by Peter Gilmore in the comedy film Carry On Henry charting the fictitious two extra wives of Henry VIII (including Marie cousin of King Francis).
+
+Francis receives a mention in a minor story in Laurence Sterne's novel Tristram Shandy. The narrator claims that the king, wishing to win the favour of Switzerland, offers to make the country the godmother of his son. When, however, their choice of name conflicts, he declares war.
+
+He is also mentioned in Jean de la Brète's novel Reine – Mon oncle et mon curé, where the main character Reine de Lavalle idolises him after reading his biography, much to the dismay of the local priest.
+
+He often receives mentions in novels on the lives of either of the Boleyn sisters – Mary Boleyn (d. 1543) and her sister, Queen Anne Boleyn (executed 1536), both of whom were for a time educated at his court. Mary had, according to several accounts, been Francis' one-time mistress and Anne had been a favourite of his sister: the novels The Lady in the Tower, The Other Boleyn Girl, The Last Boleyn, Dear Heart, How Like You This? and Mademoiselle Boleyn feature Francis in their story. He appears in Hilary Mantel's Wolf Hall about Henry VIII's minister Thomas Cromwell and is often referred to in its sequel, Bring Up the Bodies.
+
+Francis is portrayed in Diane Haeger's novel Courtesan about Diane de Poitiers and Henri II.
+
+Francis appears as the patron of Benvenuto Cellini in the 1843 French novel L'Orfèvre du roi, ou Ascanio by Alexandre Dumas, père.
+
+Samuel Shellabarger's novel The King's Cavalier describes Francis the man, and the cultural and political circumstances of his reign, in some detail.
+
+He was a recurring character in the Showtime series The Tudors, opposite Jonathan Rhys Meyers as Henry VIII and Natalie Dormer as Anne Boleyn. Francis is played by French actor, Emmanuel Leconte.
+
+He and his court set the scene for Friedrich Schiller's ballad Der Handschuh (The Glove).
+
+Francis I (played by Timothy West) and Francis's son Henry II (played by Dougray Scott) are central figures in the 1998 movie Ever After, a retelling of the Cinderella story.  The plot includes Leonardo da Vinci (played by Patrick Godfrey) arriving at Francis's court with the Mona Lisa.
+
+He is played by Alfonso Bassave in the TVE series Carlos, rey emperador, opposite Álvaro Cervantes as Charles V.

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+
+
+Francis I (French: François Ier; Middle French: Francoys; 12 September 1494 – 31 March 1547) was King of France from 1515 until his death in 1547. He was the son of Charles, Count of Angoulême, and Louise of Savoy. He succeeded his first cousin once removed and father-in-law Louis XII, who died without a son.
+
+A prodigious patron of the arts, he initiated the French Renaissance by attracting many Italian artists to work for him, including Leonardo da Vinci, who brought the Mona Lisa with him, which Francis had acquired. Francis' reign saw important cultural changes with the rise of absolute monarchy in France, the spread of humanism and Protestantism, and the beginning of French exploration of the New World. Jacques Cartier and others claimed lands in the Americas for France and paved the way for the expansion of the first French colonial empire.
+
+For his role in the development and promotion of a standardized French language, he became known as le Père et Restaurateur des Lettres (the 'Father and Restorer of Letters').[1] He was also known as François du Grand Nez ('Francis of the Large Nose'), the Grand Colas, and the Roi-Chevalier (the 'Knight-King')[1] for his personal involvement in the wars against his great rival Emperor Charles V, who was also King of Spain.
+
+Following the policy of his predecessors, Francis continued the Italian Wars. The succession of Charles V to the Burgundian Netherlands, the throne of Spain, and his subsequent election as Holy Roman Emperor meant that France was geographically encircled by the Habsburg monarchy. In his struggle against Imperial hegemony, he sought the support of Henry VIII of England at the Field of the Cloth of Gold.[2] When this was unsuccessful, he formed a Franco-Ottoman alliance with the Muslim sultan Suleiman the Magnificent, a controversial move for a Christian king at the time.[3]
+
+Francis of Orléans was born on 12 September 1494 at the Château de Cognac in the town of Cognac,[1] which at that time lay in the province of Saintonge, a part of the Duchy of Aquitaine.  Today the town lies in the department of Charente.
+
+Francis was the only son of Charles of Orléans, Count of Angoulême, and Louise of Savoy and a great-great-grandson of King Charles V of France.[4] His family was not expected to inherit the throne, as his third cousin King Charles VIII was still young at the time of his birth, as was his father's cousin the Duke of Orléans, later King Louis XII. However, Charles VIII died childless in 1498 and was succeeded by Louis XII, who himself had no male heir.[5] The Salic Law prevented women from inheriting the throne.  Therefore, the four-year-old Francis (who was already Count of Angoulême after the death of his own father two years earlier) became the heir presumptive to the throne of France in 1498 and was vested with the title of Duke of Valois.[5]
+
+In 1505, Louis XII, having fallen ill, ordered that his daughter Claude and Francis be married immediately, but only through an assembly of nobles were the two engaged.[6] Claude was heir presumptive to the Duchy of Brittany through her mother, Anne of Brittany. Following Anne's death, the marriage took place on 18 May 1514.[7] On 1 January 1515, Louis died, and Francis inherited the throne. He was crowned King of France in the Cathedral of Reims on 25 January 1515, with Claude as his queen consort.[8]
+
+As Francis was receiving his education, ideas emerging from the Italian Renaissance were influential in France. Some of his tutors, such as François Desmoulins de Rochefort (his Latin instructor, who later during the reign of Francis was named Grand Aumônier de France) and Christophe de Longueil (a Brabantian humanist), were attracted by these new ways of thinking and attempted to influence Francis. His academic education had been in arithmetic, geography, grammar, history, reading, spelling, and writing and he became proficient in Hebrew, Italian, Latin and Spanish. Francis came to learn chivalry, dancing, and music, and he loved archery, falconry, horseback riding, hunting, jousting, real tennis and wrestling. He ended up reading philosophy and theology and he was fascinated with art, literature, poetry and science. His mother, who had a high admiration for Italian Renaissance art, passed this interest on to her son. Although Francis did not receive a humanist education, he was more influenced by humanism than any previous French king.
+
+By the time he ascended the throne in 1515, the Renaissance had arrived in France, and Francis became an enthusiastic patron of the arts. At the time of his accession, the royal palaces of France were ornamented with only a scattering of great paintings, and not a single sculpture, either ancient or modern. During Francis' reign, the magnificent art collection of the French kings, which can still be seen at the Louvre Palace, was begun.
+
+Francis patronized many great artists of his time, including Andrea del Sarto and Leonardo da Vinci; the latter of whom was persuaded to make France his home during his last years. While da Vinci painted very little during his years in France, he brought with him many of his greatest works, including the Mona Lisa (known in France as La Joconde), and these remained in France after his death. Other major artists to receive Francis' patronage included the goldsmith Benvenuto Cellini and the painters Rosso Fiorentino, Giulio Romano, and Primaticcio, all of whom were employed in decorating Francis' various palaces. He also invited the noted architect Sebastiano Serlio (1475–1554), who enjoyed a fruitful late career in France.[9] Francis also commissioned a number of agents in Italy to procure notable works of art and ship them to France.
+
+Francis was also renowned as a man of letters. When Francis comes up in a conversation among characters in Baldassare Castiglione's Book of the Courtier, it is as the great hope to bring culture to the war-obsessed French nation. Not only did Francis support a number of major writers of the period, he was a poet himself, if not one of particular abilities. Francis worked diligently at improving the royal library. He appointed the great French humanist Guillaume Budé as chief librarian and began to expand the collection. Francis employed agents in Italy to look for rare books and manuscripts, just as he had agents looking for art works. During his reign, the size of the library greatly increased. Not only did he expand the library, there is also evidence[citation needed] that he read the books he bought for it, a much rarer event in the royal annals. Francis set an important precedent by opening his library to scholars from around the world in order to facilitate the diffusion of knowledge.
+
+In 1537, Francis signed the Ordonnance de Montpellier, which decreed that his library be given a copy of every book to be sold in France.  Francis' older sister, Marguerite, Queen of Navarre, was also an accomplished writer who produced the classic collection of short stories known as the Heptameron.  Francis corresponded with the abbess and philosopher Claude de Bectoz, of whose letters he was so fond that he would carry them around and show them to the ladies of his court.[10]
+Together with his sister, he visited her in Tarascon.[11][failed verification]
+
+Francis poured vast amounts of money into new structures. He continued the work of his predecessors on the Château d'Amboise and also started renovations on the Château de Blois. Early in his reign, he began construction of the magnificent Château de Chambord, inspired by the architectural styles of the Italian renaissance, and perhaps even designed by Leonardo da Vinci. Francis rebuilt the Château du Louvre, transforming it from a medieval fortress into a building of Renaissance splendour. He financed the building of a new City Hall (the Hôtel de Ville) for Paris in order to have control over the building's design. He constructed the Château de Madrid in the Bois de Boulogne and rebuilt the Château de Saint-Germain-en-Laye. The largest of Francis' building projects was the reconstruction and expansion of the Château de Fontainebleau, which quickly became his favourite place of residence, as well as the residence of his official mistress, Anne, Duchess of Étampes. Each of Francis' projects was luxuriously decorated both inside and out. Fontainebleau, for instance, had a gushing fountain in its courtyard where quantities of wine were mixed with the water.
+
+Although the Italian Wars (1494–1559) came to dominate the reign of Francis I, the wars were not the sole focus of his policies.  Francis merely continued the incessant wars that his predecessors had started and that his successors on the throne of France would drag on after Francis' death.  Indeed, the Italian Wars had begun when Milan sent a plea to King Charles VIII of France for protection against the aggressive actions of the King of Naples.[12] Militarily and diplomatically, Francis' reign was a mixed bag of success and failure.  Francis tried and failed to become Holy Roman Emperor at the Imperial election of 1519.  However, there were also temporary victories, such as in the portion of the Italian Wars called the War of the League of Cambrai (1508–1516) and, more specifically, to the final stage of that war, which history refers to simply as "Francis' First Italian War" (1515–1516), when Francis routed the combined forces of the Papal States and the Old Swiss Confederacy at Marignano on 13–15 September 1515. This victory at Marignano allowed Francis to capture the Italian city-state of Milan. Later, in November 1521, during the Four Years' War (1521–1526) and facing the advancing Imperial forces of the Holy Roman Empire and open revolt within Milan, Francis was forced to abandon Milan, thus, cancelling the triumph at Marignano.
+
+Much of the military activity of Francis's reign was focused on his sworn enemy, the Holy Roman Emperor Charles V. Francis and Charles maintained an intense personal rivalry. Charles, in fact, brashly challenged Francis to single combat multiple times. In addition to the Holy Roman Empire, Charles personally ruled Spain, Austria, and a number of smaller possessions neighboring France. He was thus a constant threat to Francis' kingdom.
+
+Francis attempted to arrange an alliance with Henry VIII of England at the famous meeting at the Field of Cloth of Gold on 7 June 1520, but despite a lavish fortnight of diplomacy they failed to reach an agreement.[13]
+
+Francis suffered his most devastating defeat at the Battle of Pavia on 24 February 1525, during part of the continuing Italian Wars known as the Four Years' War. Francis was actually captured by the forces of Charles V after Cesare Hercolani was able to injure his horse, leading Francis to be captured by Diego Dávila, Alonso Pita da Veiga and Juan de Urbieta, from Guipúzcoa. For this reason, Hercolani was named "Victor of the battle of Pavia". Zuppa alla Pavese was supposedly invented on the spot to feed the captive king right after the battle.[14] There are allegations that Francis would have been killed by mistake by one of Charles' soldiers had Pedro de Valdivia —the future conqueror of Chile— not intervened.[15]
+
+Francis I was held captive in Madrid. In a letter to his mother he wrote, "Of all things, nothing remains to me but honour and life, which is safe." This line has come down in history famously as "All is lost save honour."[16] In the Treaty of Madrid, signed on 14 January 1526, Francis was forced to make major concessions to Charles V before he was freed on 17 March 1526. An ultimatum from Ottoman Sultan Suleiman to Charles V also played an important role in his release. Among the concessions that Francis I yielded to Charles V were the surrender of any claims to Naples and Milan in Italy.[17] Francis I was also forced to recognise the independence of the duchy of Burgundy, which had become part of France since the death of Charles, Duke of Burgundy on 5 January 1477,[18] during the reign of Louis XI.
+
+Furthermore, France was required to give up all claims to Flanders and the Artois.[17] Additionally, Francis I was allowed to return to France in exchange for his two sons, Francis and Henry, but once he was free he argued that his agreement with Charles was made under duress. He also claimed that the agreement was void because his sons were taken hostage with the implication that his word alone could not be trusted. Thus he firmly repudiated it.
+
+Francis persevered in his hatred of Charles V and desire to control Italy by conquest. The repudiation of the Treaty of Madrid led to the War of the League of Cognac of 1526–30. By the mid-1520s, Pope Clement VII wished to liberate Italy from foreign domination, especially that of Charles V, so to that end he negotiated with Venice to form the League of Cognac. Francis I willingly joined this anti-Imperial league on 22 May 1526.[19]
+
+After the league failed, Francis concluded a secret alliance with the Landgrave of Hesse on 27 January 1534. This was directed against Charles V on the pretext of assisting the Duke of Wurttemberg to regain his traditional seat, from which Charles had removed him in 1519. Francis also obtained the help of the Ottoman Empire and renewed the contest in Italy in the Italian War of 1536–1538 after the death of Francesco II Sforza, the ruler of Milan. This round of fighting, which had little result, was ended by the Truce of Nice. The agreement collapsed, however, which led to Francis' final attempt on Italy in the Italian War of 1542–1546. This time Francis managed to hold off the forces of Charles V and England's Henry VIII. Charles V was forced to sign the Treaty of Crépy because of his financial difficulties and conflicts with the Schmalkaldic League.
+
+Francis had been much aggrieved at the papal bull Aeterni regis: in June 1481 Portuguese rule over Africa and the Indies was confirmed by Pope Sixtus IV. Thirteen years later, on 7 June 1494, Portugal and the Crown of Castille signed the Treaty of Tordesillas under which the newly discovered lands would be divided between the two signatories. All this prompted King Francis to declare, "The sun shines for me as it does for others. I would very much like to see the clause of Adam’s will by which I should be denied my share of the world."[20]
+
+In order to counterbalance the power of the Habsburg Empire under Charles V, especially its control of large parts of the New World through the Crown of Spain, Francis I endeavoured to develop contacts with the New World and Asia. Fleets were sent to the Americas and the Far East, and close contacts were developed with the Ottoman Empire permitting the development of French Mediterranean trade as well as the establishment of a strategic military alliance.
+
+The port city now known as Le Havre was founded in 1517 during the early years of Francis' reign. The construction of a new port was urgently needed in order to replace the ancient harbours of Honfleur and Harfleur, whose utility had decreased due to silting. Le Havre was originally named Franciscopolis after the King who founded it, but this name did not survive into later reigns.
+
+In 1524, Francis assisted the citizens of Lyon in financing the expedition of Giovanni da Verrazzano to North America. On this expedition, Verrazzano visited the present site of New York City, naming it New Angoulême, and claimed Newfoundland for the French crown. Verrazzano's letter to Francis of 8 July 1524 is known as the Cèllere Codex.[21]
+
+In 1531, Bertrand d'Ornesan tried to establish a French trading post at Pernambuco, Brazil.[22]
+
+In 1534, Francis sent Jacques Cartier to explore the St. Lawrence River in Quebec to find "certain islands and lands where it is said there must be great quantities of gold and other riches".[23] In 1541, Francis sent Jean-François de Roberval to settle Canada and to provide for the spread of "the Holy Catholic faith."
+
+French trade with East Asia was initiated during the reign of Francis I with the help of shipowner Jean Ango. In July 1527, a French Norman trading ship from the city of Rouen is recorded by the Portuguese João de Barros as having arrived in the Indian city of Diu.[24] In 1529, Jean Parmentier, on board the Sacre and the Pensée, reached Sumatra.[24][25] Upon its return, the expedition triggered the development of the Dieppe maps, influencing the work of Dieppe cartographers such as Jean Rotz.[26]
+
+Under the reign of Francis I, France became the first country in Europe to establish formal relations with the Ottoman Empire and to set up instruction in the Arabic language under the guidance of Guillaume Postel at the Collège de France.[27]
+
+In a watershed moment in European diplomacy, Francis came to an understanding with the Ottoman Empire that developed into a Franco-Ottoman alliance. The alliance has been called "the first nonideological diplomatic alliance of its kind between a Christian and non-Christian empire".[28] It did, however, cause quite a scandal in the Christian world[29] and was designated "the impious alliance", or "the sacrilegious union of the [French] Lily and the [Ottoman] Crescent." Nevertheless, it endured for many years, since it served the objective interests of both parties.[30] The two powers colluded against Charles V, and in 1543 they even combined for a joint naval assault in the Siege of Nice.
+
+In 1533, Francis I sent colonel Pierre de Piton as ambassador to Morocco, initiating official France-Morocco relations.[31] In a letter to Francis I dated 13 August 1533, the Wattassid ruler of Fez, Ahmed ben Mohammed, welcomed French overtures and granted freedom of shipping and protection of French traders.
+
+Francis took several steps to eradicate the monopoly of Latin as the language of knowledge. In 1530, he declared French the national language of the kingdom, and that same year opened the Collège des trois langues, or Collège Royal, following the recommendation of humanist Guillaume Budé. Students at the Collège could study Greek, Hebrew and Aramaic, then Arabic under Guillaume Postel beginning in 1539.[32]
+
+In 1539, in his castle in Villers-Cotterêts,[33] Francis signed the important edict known as Ordinance of Villers-Cotterêts, which, among other reforms, made French the administrative language of the kingdom as a replacement for Latin. This same edict required priests to register births, marriages, and deaths, and to establish a registry office in every parish. This initiated the first records of vital statistics with filiations available in Europe.
+
+Divisions in Christianity in Western Europe during Francis' reign created lasting international rifts. Martin Luther's preaching and writing sparked the Protestant Reformation, which spread through much of Europe, including France.
+
+Initially, Francis was relatively tolerant of the new movement, under the influence of his beloved sister Marguerite de Navarre, who was genuinely attracted by Luther's theology. He even considered it politically useful, as it caused many German princes to turn against his enemy Charles V. In 1533 Francis even dared to suggest to Pope Clement VII that he convene a church council in which Catholic and Protestant rulers would have an equal vote in order to settle their differences – an offer rejected by both the Pope and Charles V. Beginning in 1523, however, Francis burned several heretics at the Place Maubert.[34]
+
+Francis' attitude towards Protestantism changed for the worse following the "Affair of the Placards", on the night of 17 October 1534, in which notices appeared on the streets of Paris and other major cities denouncing the Catholic mass. The most fervent Catholics were outraged by the notice's allegations. Francis himself came to view the movement as a plot against him and began to persecute its followers. Protestants were jailed and executed. In some areas whole villages were destroyed. In Paris, after 1540, Francis had heretics such as Etienne Dolet tortured and burned.[35] Printing was censored and leading Protestant reformers such as John Calvin were forced into exile. The persecutions soon numbered thousands of dead and tens of thousands of homeless.[36]
+
+Persecutions against Protestants were codified in the Edict of Fontainebleau (1540) issued by Francis. Major acts of violence continued, as when Francis ordered the execution of one of the historical pre-Lutheran groups, the Waldensians, at the Massacre of Mérindol in 1545.
+
+Francis died at the Château de Rambouillet on 31 March 1547, on his son and successor's 28th birthday. It is said that "he died complaining about the weight of a crown that he had first perceived as a gift from God".[37] He was interred with his first wife, Claude, Duchess of Brittany, in Saint Denis Basilica. He was succeeded by his son, Henry II.
+
+Francis' tomb and that of his wife and mother, along with the tombs of other French kings and members of the royal family, were desecrated on 20 October 1793 during the Reign of Terror at the height of the French Revolution.
+
+Francis' personal emblem was the salamander and his Latin motto was Nutrisco et extinguo ("I nourish [the good] and extinguish [the bad]").[citation needed]
+
+His long nose earned him the nickname François du Grand Nez ("Francis of the Big Nose"), he was also colloquially known as the "Grand Colas" or "Bonhomme Colas". For his personal involvement in battles, he was known as le Roi-Chevalier ("the Knight-King") or the le Roi-Guerrier ("the Warrior-King").[38]
+
+On 18 May 1514, Francis married his second cousin Claude, the daughter of King Louis XII of France and Duchess Anne of Brittany. The couple had seven children:
+
+On 7 July 1530, Francis I married his second wife Eleanor of Austria,[39] 
+a sister of the Emperor Charles V. The couple had no children. During his reign, Francis kept two official mistresses at court. The first was Françoise de Foix, Countess of Châteaubriant. In 1526, she was replaced by the blonde-haired, cultured Anne de Pisseleu d'Heilly, Duchess of Étampes who, with the death of Queen Claude two years earlier, wielded far more political power at court than her predecessor had done. Another of his earlier mistresses was allegedly Mary Boleyn, mistress of King Henry VIII and sister of Henry's future wife, Anne Boleyn.[40]
+
+The amorous exploits of Francis inspired the 1832 play by Fanny Kemble, Francis the First, and the 1832 play by Victor Hugo, Le Roi s'amuse ("The King's Amusement"), which featured the jester Triboulet, the inspiration for the 1851 opera Rigoletto by Giuseppe Verdi.
+
+Francis was first played in a George Méliès movie by an unknown actor in 1907, and has also been played by Claude Garry (1910), Aimé Simon-Girard (1937), Sacha Guitry (1937), Gérard Oury (1953), Jean Marais (1955), Pedro Armendáriz (1956), Claude Titre (1962), Bernard Pierre Donnadieu (1990). Timothy West (1998) and Emmanuel Leconte (2007– 2010).
+
+Francis was portrayed by Peter Gilmore in the comedy film Carry On Henry charting the fictitious two extra wives of Henry VIII (including Marie cousin of King Francis).
+
+Francis receives a mention in a minor story in Laurence Sterne's novel Tristram Shandy. The narrator claims that the king, wishing to win the favour of Switzerland, offers to make the country the godmother of his son. When, however, their choice of name conflicts, he declares war.
+
+He is also mentioned in Jean de la Brète's novel Reine – Mon oncle et mon curé, where the main character Reine de Lavalle idolises him after reading his biography, much to the dismay of the local priest.
+
+He often receives mentions in novels on the lives of either of the Boleyn sisters – Mary Boleyn (d. 1543) and her sister, Queen Anne Boleyn (executed 1536), both of whom were for a time educated at his court. Mary had, according to several accounts, been Francis' one-time mistress and Anne had been a favourite of his sister: the novels The Lady in the Tower, The Other Boleyn Girl, The Last Boleyn, Dear Heart, How Like You This? and Mademoiselle Boleyn feature Francis in their story. He appears in Hilary Mantel's Wolf Hall about Henry VIII's minister Thomas Cromwell and is often referred to in its sequel, Bring Up the Bodies.
+
+Francis is portrayed in Diane Haeger's novel Courtesan about Diane de Poitiers and Henri II.
+
+Francis appears as the patron of Benvenuto Cellini in the 1843 French novel L'Orfèvre du roi, ou Ascanio by Alexandre Dumas, père.
+
+Samuel Shellabarger's novel The King's Cavalier describes Francis the man, and the cultural and political circumstances of his reign, in some detail.
+
+He was a recurring character in the Showtime series The Tudors, opposite Jonathan Rhys Meyers as Henry VIII and Natalie Dormer as Anne Boleyn. Francis is played by French actor, Emmanuel Leconte.
+
+He and his court set the scene for Friedrich Schiller's ballad Der Handschuh (The Glove).
+
+Francis I (played by Timothy West) and Francis's son Henry II (played by Dougray Scott) are central figures in the 1998 movie Ever After, a retelling of the Cinderella story.  The plot includes Leonardo da Vinci (played by Patrick Godfrey) arriving at Francis's court with the Mona Lisa.
+
+He is played by Alfonso Bassave in the TVE series Carlos, rey emperador, opposite Álvaro Cervantes as Charles V.

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+
+
+Francis II (French: François II; 19 January 1544 – 5 December 1560) was King of France from 1559 to 1560. He was also King consort of Scotland as a result of his marriage to Mary, Queen of Scots, from 1558 until his death in 1560.
+
+He ascended the throne of France at the age of fifteen after the accidental death of his father, Henry II, in 1559. His short reign was dominated by the first stirrings of the French Wars of Religion.
+
+Although the royal age of majority had been set at fourteen, his mother, Catherine de' Medici, entrusted the reins of government to his wife's uncles from the House of Guise, staunch supporters of the Catholic cause. They were unable to help Catholics in Scotland against the progressing Scottish Reformation, however, and the Auld Alliance was dissolved.
+
+Francis was succeeded by two of his brothers in turn, both of whom were also unable to reduce tensions between Protestants and Catholics.
+
+Born eleven years after his parents' wedding, the long delay in producing an heir may have been due to his father's repudiation of his mother in favour of his mistress Diane de Poitiers,[1] however this repudiation was negated by Diane's insistence that Henry spend his nights with Catherine.[1] Francis was at first raised at the Château de Saint-Germain-en-Laye. He was baptised on 10 February 1544 at the Chapelle des Trinitaires in Fontainebleau. His godparents were Francis I (who knighted him during the ceremony), Pope Paul III, and his great-aunt Marguerite de Navarre. He became governor of Languedoc in 1546, and Dauphin of France in 1547, when his grandfather Francis I died.
+
+Francis's governor and governess were Jean d'Humières and Françoise d'Humières, and his tutor was Pierre Danès, a Greek scholar originally from Naples. He learned dancing from Virgilio Bracesco and fencing from Hector of Mantua.
+
+King Henry II, his father, arranged a remarkable betrothal for his son to Mary, Queen of Scots, in the Châtillon agreement of 27 January 1548, when Francis was only four years old. Mary had been crowned Queen of Scotland in Stirling Castle on 9 September 1543 at the age of nine months following the death of her father James V. Besides being the queen of Scotland, Mary was a granddaughter of Claude, Duke of Guise, a very influential figure at the court of France. Once the marriage agreement was formally ratified, the six-year-old Mary was sent to France to be raised at court until the marriage. Although Mary was tall for her age and eloquent, her betrothed Francis was unusually short and stuttered. Henry II commented that "from the very first day they met, my son and she got on as well together as if they had known each other for a long time".[2]
+
+On 24 April 1558, the fourteen-year-old Dauphin married the Queen of Scots in Notre Dame Cathedral in Paris. It was a union that could have given the future kings of France the throne of Scotland and also a claim to the throne of England through Mary's great grandfather, King Henry VII of England. As a result of the marriage, Francis became King Consort in Scotland until his death. The marriage produced no children, possibly due to Francis' illnesses or his undescended testicles.[3]
+
+A little over a year after his marriage, on 10 July 1559, Francis became king at the age of fifteen upon the death of his father Henry II, who had been killed in a jousting accident. On 21 September 1559, Francis II was crowned king in Reims by his uncle Charles, Cardinal of Lorraine. The crown was so heavy that nobles had to hold it in place for him.[4] The court then moved to the Loire Valley, where the Château de Blois and the surrounding forests were the new king's home. Francis II took the sun for his emblem and for his mottoes Spectanda fides (This is how faith should be respected) and Lumen rectis (Light for the righteous).
+
+According to French law, Francis at the age of fifteen was an adult who in theory did not need a regent.[5] But since he was young, inexperienced, and in fragile health, he delegated his power to his wife's uncles from the noble House of Guise: Francis, Duke of Guise, and Charles, Cardinal of Lorraine. His mother, Catherine de' Medici, agreed to this delegation. On the first day of his reign, Francis II instructed his four ministers to take orders from his mother, but since she was still in mourning for the loss of her husband, she directed them to the House of Guise.[6]
+
+The two eldest brothers of the House of Guise had already had major roles in the reign of Henry II. Francis, Duke of Guise, was one of the most famous military commanders in the royal army, and the Cardinal of Lorraine had participated in the most important negotiations and matters of the kingdom. After the young king ascended the throne, the two brothers split the custody of the kingdom: Francis became head of the army and Charles the head of finance, justice, and diplomacy.[7]
+
+The rise of the House of Guise worked to the detriment of its old rival, Anne de Montmorency, Constable of France. At the new king's suggestion, he left the court for his estates to get some rest. Diane de Poitiers, the mistress of the previous king, was also asked not to appear at court. Her protégé Jean Bertrand had to surrender his title Keeper of the Seals of France to chancellor François Olivier, whom Diane had removed from this position a few years earlier. It was a palace revolution.
+
+The transition has been described as brutal, but while it no doubt caused the Constable considerable frustration, there were no confrontations or reprisals. Anne de Montmorency remained tied to power. As soon as the day after the death of the king, he was present at the council meeting and was also at the coronation. Later he supported the repression of the Amboise conspiracy of 1560, notably by going to the Parlement of Paris to communicate to its members the measures taken by the king. In July 1560 he came back to court and to the council, although in a much less flamboyant manner than before.[8] The Guises were now the new masters of the court. The king granted them numerous favours and privileges,[9][10] one of the most significant being the title of Grand Master of France, a title until then held by the son of the Constable, François de Montmorency.
+
+The reign of Francis II was dominated by religious crisis. His unpopular and repressive policy toward Protestantism motivated the Amboise conspiracy, in which certain Protestant leaders attempted a coup d'état against the king and the House of Guise. Due to growing discontent, the government tried conciliation. Under the influence of Catherine de' Medici, it started a dialogue with the proponents of this relatively new movement, while remaining implacable towards agitators. Until the end of his reign, the French kingdom was paralysed by local revolts. He reacted by becoming more authoritarian.
+
+From the beginning of their regency, the Guises faced deep discontent throughout the kingdom. The opposition was led by two Princes of the Blood who contested their power and their decisions as rulers.
+
+The Guises were seen by many as lacking legitimacy. To their adversaries, they were merely ambitious foreigners from Lorraine. Their father Claude, Duke of Guise, was the son of René II, Duke of Lorraine, who had been accorded French citizenship by King Francis I, his military companion.[10] The main criticism against the Guises was that they were taking advantage of the king's youth to wield power arbitrarily. An opposition movement led by the Prince of the Blood Antoine of Navarre, King of Navarre, contested their power. Some theorists, such as François Hotman, believed that the law entitled the latter to be the king's senior adviser since he was a descendant of Louis IX of France and thus an heir to the throne if the House of Valois then in power disappeared. However, Antoine failed to prevail against the Guises when he came to court.
+
+The political decisions of the government were also contested. The Guises faced a disastrous financial situation. After decades of wars against the House of Habsburg, the public debt stood at 48 million livres, while the king had only 12 million livres in annual income. The Guises implemented a policy of austerity intended to improve the country's financial situation, but this contributed mightily to their unpopularity.[11] They also delayed paying military personnel, the king's officials, and court suppliers. They reduced the size of the army, and many soldiers became unemployed. Frustrations mounted at court, as the cutbacks spared the regiments under the control of the Guises and their friends.
+
+In religion, the Guises increased the repression of Protestantism started by King Henry II. The autumn of 1559 saw a wave of house searches, arrests, and asset forfeitures.[12] On 23 December 1559, the counsellor-clerk Anne du Bourg, magistrate at the Parlement of Paris, which had contested the repression, was publicly executed in Paris at the Place de Grève.
+
+Determined to stop the persecution and have Protestantism officially recognised, a group of noblemen planned the Amboise conspiracy to overthrow the government and give power to the Princes of the Blood, who supported the new religion. The conspirators planned to take over the palace with the help of the royal guard, abduct the king, then eliminate the Guises if they offered any resistance. A substantial external military deployment was intended to secure the operation.[13] The conspirators also most likely had the secret support of Louis, Prince of Condé, the ambitious younger brother of King Antoine of Navarre.
+
+During February 1560, the court received multiple warnings about the conspiracy. Due to that threat, the royal council decided, under the influence of Queen Catherine de' Medici, to make some concessions. On 8 March 1560, the king signed an edict granting general amnesty to Protestants.[14] But it was too late; the conspiracy was already under way. From all parts of the kingdom, troops were on their way to the Château d'Amboise, where the court was in residence. In the cities of Tours and Orléans, they received money and weapons from the conspirators.
+
+The poorly organised conspiracy ended in a bloodbath. Its outcome was determined as early as 15 March when Jacques, Duke of Nemours, arrested some of the primary conspirators. Over the following days disorientated troops, mostly peasants, were arrested one by one in and around the forest of Amboise. The king was at first inclined to leniency. He freed them and ordered them to return to their homes. But on 17 March, two hundred men tried to storm one of the city gates at the foot of the castle. Quickly repelled by the Duke of Guise, these rebels were unmercifully pursued. More than a hundred were executed, some even hanged from the ramparts of the castle. The retaliation continued for several weeks, and almost twelve hundred people died.
+
+The Guises were less certain how to handle the Prince of Condé. He had arrived at court during the uprising and helped to defend the castle. Interrogation of prisoners clearly placed him as the conspiracy's beneficiary, but the word of commoners did not count against that of a Prince of the Blood. Irrefutable written proof was needed to accuse him. Since he was still free, Condé left the court to meet his brother Antoine in the south-west.[15]
+
+The outburst of violence caused by the Amboise conspiracy made the court decide that persecuting Protestants only made the religious crisis worse. Under the influence of Catherine de Médicis and the members of the royal council, the government tried to ease tensions with a policy of conciliation.[16]
+
+Clemency towards Protestants became policy. Public assemblies were still prohibited, but the government released all religious prisoners. This was the first easing of religious persecution since the reign of Henry II.[17] An edict signed at Romorantin in May 1560 was the beginning of the right to freedom of conscience in France.[18]
+
+In April 1560, the Queen Mother had Michel de l'Hôpital named Lord Chancellor of France. The government was then dominated by "averagers", humanists convinced that reconciliation among Christians was possible, based on reciprocal concessions.[19] Charles, Cardinal of Lorraine, was himself open to church reform. An ecumenical council for the church of France was officially proposed: instead of gaining the consent of Pope Pius IV, the cardinal and the Queen Mother called for a general council in which Christians of all opinions and from all over Europe would meet to reform the religion. The Pope opposed this. Even though they did not want to split from Rome, the Pope's opposition led them to threaten a national council if he did not agree.[20]
+
+To mitigate criticism of the king based on his youth, the government tried to win him approval by communicating his decisions themselves. A gathering of the Estates General was suggested, but, fearing that they would be evicted due to their unpopularity, the Guises strongly opposed this. Under pressure from the Queen Mother, the Guises agreed to consult with the notables: this led to a meeting of the Assembly of Notables at Fontainebleau from 21 to 26 August. The Princes of the Blood and the Constable were asked to attend and to resume their roles in the king's council.[21] During this assembly, the Admiral of Coligny, future head of the Protestants, had a petition from Norman Protestants read before an amazed court that asked for freedom of religion. The assembly closed by convening the Estates General.
+
+Highly critical of the Pope, the Assembly of Notables also decided to gather France's bishops to obtain their consent for a national council. Afraid to see gallicanism slip out of his control, the Pope eventually agreed to a general council, but rejected the attendance of any Protestant, as demanded by the French government.[22] This decision led to the re-opening of the Council of Trent.
+
+The government's conciliation policy was intended to ease tensions, but had the opposite effect. Encouraged by the government's leniency, Protestants continued to congregate for religious services. Although law officials intervened to disperse them and to imprison the organizers, the growing numbers of participants, which sometimes exceeded a thousand, made it impossible to accomplish this for lack of resources. Some were even won over to the new religion. In some places Protestants challenged royal authority with riots and armed rebellions. The unrest that had started sporadically during the Amboise conspiracy spread over the summer throughout the kingdom. The main areas of opposition spanned a crescent-shaped territory from Anjou to Dauphiné and included the regions of Poitou, Guyenne, Périgord, Languedoc, and Provence.
+
+The rioters frequently had the support of local notables. Motivated by fierce propaganda against the Guises, and seeking revenge for the stamping out of the Amboise conspiracy, the boldest attacked castles, jails, and churches. During the spring of 1560, the kingdom experienced the first major events of iconoclasm in Provence.[23] During the summer, the civil disobedience movement gained intensity; several cities in southern France were in revolt.[24][25]
+
+With the secret support of the two Princes of the Blood, Condé and Navarre, a political-military organisation gradually developed. Protestants elected local leaders, raised money, bought weapons, and formed militias. Armed gangs from Languedoc went to Provence and Dauphiné, which Paul de Mouvans and Charles de Montbrun were trying respectively to enlist into the insurrection. The climax came during the night of 4 and 5 September, when Protestant militias tried to take over the city of Lyon.
+
+The king's reaction was fierce and determined: he mobilised his troops, sent the army to the rioting areas, and ordered governors to return to their positions.[26] By autumn, order was slowly restored. Convinced that the Prince of Condé was responsible for the uprising, the king summoned him to court and had him arrested on 31 October 1560.
+
+In foreign policy, Francis II continued peace efforts begun by Henry II with the signing of the Peace of Cateau-Cambrésis in April 1559, which ended 40 years of war between France and the Habsburg empire. At the expense of its influence in Europe, France continued to restore lands conquered over the previous 40 years. In this sense, the reign of Francis II began the decline of French influence throughout Europe, to the benefit of Spain.[27][28]
+
+When King Henry II died, the restitution of these territories was well under way. Francis II, aware of the kingdom's weaknesses, reassured Spain of its intention to fulfill the treaty just signed.[29] The Maréchal de Brissac, who displayed some unwillingness to evacuate Piedmont, was asked to change his behaviour and accelerate the withdrawal.[30][31][32] By the autumn of 1559, France had completely left Savoy, and Piedmont, except for the five locations agreed upon in the Peace of Cateau-Cambrésis. If these were returned to the Duke of Savoy Emmanuel Philibert, Montferrat would be returned to Guglielmo Gonzaga, Duke of Mantua. Both were allies of Spain. Finally, Valenza, which Brissac was grumbling about releasing, was to be returned to the Spanish Duchy of Milan. On the Spanish side, King Philip II showed some unwillingness to return four locations in the north-east of the kingdom as required by the treaty. Border disputes renewed tensions between the two nations, but after months of protests Francis II finally obtained these territories.[33][34]
+
+Along with restitution of territories, the government of Francis II had to negotiate, pay, or claim compensations for people whose properties were taken or destroyed during the war.[35][36] It also had to reach an agreement with Spain regarding the prisoners of war held by both sides. Many noblemen were still prisoners and unable to pay their ransom. Common soldiers were consigned to use as rowers on the royal galleys. Even after a reciprocal release compromise was signed, Spain was not eager to lose its prisoners.[37][38][39]
+
+When Francis II died, France withdrew from Scotland, Brazil, Corsica, Tuscany, Savoy and most of Piedmont.
+
+With the marriage of Francis II and Mary Stuart, the future of Scotland was linked to that of France. A secret clause signed by the queen provided that Scotland would become part of France if the royal couple did not have children.[40] The queen's mother, Marie of Guise, was already regent for Scotland.
+
+Because of French control over their country, a congregation of Scottish lords organised an uprising and made the regent and her French councils leave the capital, Edinburgh, in May 1559. Having taken refuge at the fortress of Dunbar, Marie of Guise asked France for help. Francis II and Mary Stuart sent troops right away. By the end of 1559, France had regained control of Scotland.[41]
+
+Nothing seemed to stand in the way of France controlling Scotland apart from English support for the uprising of the Scottish nobles. Queen Elizabeth I of England was still offended that Francis II and Mary Stuart had put on their coat of arms those of England, thus proclaiming Mary's claims on the throne of England.[42] In January 1560, the English fleet blockaded the port of Leith, which French troops had turned into a military base. They were supported by the arrival in April of 6000 soldiers and 3000 horsemen, which began the siege of the city.
+
+Just as English troops were not particularly successful, the French troops found themselves in a better strategic position. But the poor financial situation of the French government and internal turmoil in the French kingdom prevented any military reinforcements from being sent.[43][44] When the Bishop of Valence and Charles de La Rochefoucault, sieur of Randan, sent by the king to negotiate, arrived in Scotland, they were treated almost like prisoners. With Marie of Guise shut up in an Edinburgh fortress, the two men were forced to negotiate a peace that was disadvantageous to France. On 6 July 1560, they signed the Treaty of Edinburgh, which ended French occupation of Scotland. Francis II and Mary Stuart had to withdraw French troops and stop displaying England's arms.
+
+A few weeks later, Scotland's parliament established Protestantism as the state religion. When Francis II and Mary Stuart were presented with the Treaty of Edinburgh, they were outraged and refused to sign it; they also challenged the legitimacy of the Scottish parliament's decision.[45]
+
+The health of the king deteriorated in November 1560. On 16 November he fainted. After only 17 months on the throne, Francis II died on 5 December 1560 in Orléans, Loiret, from an ear condition. Multiple diseases have been suggested, such as mastoiditis, meningitis, or otitis exacerbated into an abscess. Ambroise Paré, the royal surgeon, considered performing a trepanation. Some suspected Protestants of having poisoned the king, a view held by Catholics as the tensions between them and Protestants were on the rise; however, this has not been proven.
+
+Francis II died childless, so his younger brother Charles, then ten years old, succeeded him. On 21 December, the council named Catherine de Médici as Regent of France. The Guises left the court, while Mary Stuart, Francis II's widow, returned to Scotland. Louis, Prince of Condé, who was jailed and awaiting execution, was freed after some negotiations with Catherine de Médici.
+
+On 23 December 1560, the body of Francis II was interred in the Basilica of Saint-Denis by the Prince of La Roche-sur-Yon.
+
+Francis II had a brief reign. He became king as an inexperienced teenager, at a time when the kingdom was struggling with religious troubles. Historians agree that Francis II was fragile, both physically and psychologically, and his frail health led to his early death.[46] The question of whether his marriage was consummated or not remains unanswered.
+
+Royal arms of Francis, Dauphin and King consort of Scots
+
+Royal arms of Mary, Queen of Scots, impaled with those of Francis
+
+Royal arms of Francis II
+
+Royal arms of Mary, Queen of Scots, Queen consort of France
+
+Royal arms of Mary, Queen of Scots, Queen dowager of France
+

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+Francis II (French: François II; 19 January 1544 – 5 December 1560) was King of France from 1559 to 1560. He was also King consort of Scotland as a result of his marriage to Mary, Queen of Scots, from 1558 until his death in 1560.
+
+He ascended the throne of France at the age of fifteen after the accidental death of his father, Henry II, in 1559. His short reign was dominated by the first stirrings of the French Wars of Religion.
+
+Although the royal age of majority had been set at fourteen, his mother, Catherine de' Medici, entrusted the reins of government to his wife's uncles from the House of Guise, staunch supporters of the Catholic cause. They were unable to help Catholics in Scotland against the progressing Scottish Reformation, however, and the Auld Alliance was dissolved.
+
+Francis was succeeded by two of his brothers in turn, both of whom were also unable to reduce tensions between Protestants and Catholics.
+
+Born eleven years after his parents' wedding, the long delay in producing an heir may have been due to his father's repudiation of his mother in favour of his mistress Diane de Poitiers,[1] however this repudiation was negated by Diane's insistence that Henry spend his nights with Catherine.[1] Francis was at first raised at the Château de Saint-Germain-en-Laye. He was baptised on 10 February 1544 at the Chapelle des Trinitaires in Fontainebleau. His godparents were Francis I (who knighted him during the ceremony), Pope Paul III, and his great-aunt Marguerite de Navarre. He became governor of Languedoc in 1546, and Dauphin of France in 1547, when his grandfather Francis I died.
+
+Francis's governor and governess were Jean d'Humières and Françoise d'Humières, and his tutor was Pierre Danès, a Greek scholar originally from Naples. He learned dancing from Virgilio Bracesco and fencing from Hector of Mantua.
+
+King Henry II, his father, arranged a remarkable betrothal for his son to Mary, Queen of Scots, in the Châtillon agreement of 27 January 1548, when Francis was only four years old. Mary had been crowned Queen of Scotland in Stirling Castle on 9 September 1543 at the age of nine months following the death of her father James V. Besides being the queen of Scotland, Mary was a granddaughter of Claude, Duke of Guise, a very influential figure at the court of France. Once the marriage agreement was formally ratified, the six-year-old Mary was sent to France to be raised at court until the marriage. Although Mary was tall for her age and eloquent, her betrothed Francis was unusually short and stuttered. Henry II commented that "from the very first day they met, my son and she got on as well together as if they had known each other for a long time".[2]
+
+On 24 April 1558, the fourteen-year-old Dauphin married the Queen of Scots in Notre Dame Cathedral in Paris. It was a union that could have given the future kings of France the throne of Scotland and also a claim to the throne of England through Mary's great grandfather, King Henry VII of England. As a result of the marriage, Francis became King Consort in Scotland until his death. The marriage produced no children, possibly due to Francis' illnesses or his undescended testicles.[3]
+
+A little over a year after his marriage, on 10 July 1559, Francis became king at the age of fifteen upon the death of his father Henry II, who had been killed in a jousting accident. On 21 September 1559, Francis II was crowned king in Reims by his uncle Charles, Cardinal of Lorraine. The crown was so heavy that nobles had to hold it in place for him.[4] The court then moved to the Loire Valley, where the Château de Blois and the surrounding forests were the new king's home. Francis II took the sun for his emblem and for his mottoes Spectanda fides (This is how faith should be respected) and Lumen rectis (Light for the righteous).
+
+According to French law, Francis at the age of fifteen was an adult who in theory did not need a regent.[5] But since he was young, inexperienced, and in fragile health, he delegated his power to his wife's uncles from the noble House of Guise: Francis, Duke of Guise, and Charles, Cardinal of Lorraine. His mother, Catherine de' Medici, agreed to this delegation. On the first day of his reign, Francis II instructed his four ministers to take orders from his mother, but since she was still in mourning for the loss of her husband, she directed them to the House of Guise.[6]
+
+The two eldest brothers of the House of Guise had already had major roles in the reign of Henry II. Francis, Duke of Guise, was one of the most famous military commanders in the royal army, and the Cardinal of Lorraine had participated in the most important negotiations and matters of the kingdom. After the young king ascended the throne, the two brothers split the custody of the kingdom: Francis became head of the army and Charles the head of finance, justice, and diplomacy.[7]
+
+The rise of the House of Guise worked to the detriment of its old rival, Anne de Montmorency, Constable of France. At the new king's suggestion, he left the court for his estates to get some rest. Diane de Poitiers, the mistress of the previous king, was also asked not to appear at court. Her protégé Jean Bertrand had to surrender his title Keeper of the Seals of France to chancellor François Olivier, whom Diane had removed from this position a few years earlier. It was a palace revolution.
+
+The transition has been described as brutal, but while it no doubt caused the Constable considerable frustration, there were no confrontations or reprisals. Anne de Montmorency remained tied to power. As soon as the day after the death of the king, he was present at the council meeting and was also at the coronation. Later he supported the repression of the Amboise conspiracy of 1560, notably by going to the Parlement of Paris to communicate to its members the measures taken by the king. In July 1560 he came back to court and to the council, although in a much less flamboyant manner than before.[8] The Guises were now the new masters of the court. The king granted them numerous favours and privileges,[9][10] one of the most significant being the title of Grand Master of France, a title until then held by the son of the Constable, François de Montmorency.
+
+The reign of Francis II was dominated by religious crisis. His unpopular and repressive policy toward Protestantism motivated the Amboise conspiracy, in which certain Protestant leaders attempted a coup d'état against the king and the House of Guise. Due to growing discontent, the government tried conciliation. Under the influence of Catherine de' Medici, it started a dialogue with the proponents of this relatively new movement, while remaining implacable towards agitators. Until the end of his reign, the French kingdom was paralysed by local revolts. He reacted by becoming more authoritarian.
+
+From the beginning of their regency, the Guises faced deep discontent throughout the kingdom. The opposition was led by two Princes of the Blood who contested their power and their decisions as rulers.
+
+The Guises were seen by many as lacking legitimacy. To their adversaries, they were merely ambitious foreigners from Lorraine. Their father Claude, Duke of Guise, was the son of René II, Duke of Lorraine, who had been accorded French citizenship by King Francis I, his military companion.[10] The main criticism against the Guises was that they were taking advantage of the king's youth to wield power arbitrarily. An opposition movement led by the Prince of the Blood Antoine of Navarre, King of Navarre, contested their power. Some theorists, such as François Hotman, believed that the law entitled the latter to be the king's senior adviser since he was a descendant of Louis IX of France and thus an heir to the throne if the House of Valois then in power disappeared. However, Antoine failed to prevail against the Guises when he came to court.
+
+The political decisions of the government were also contested. The Guises faced a disastrous financial situation. After decades of wars against the House of Habsburg, the public debt stood at 48 million livres, while the king had only 12 million livres in annual income. The Guises implemented a policy of austerity intended to improve the country's financial situation, but this contributed mightily to their unpopularity.[11] They also delayed paying military personnel, the king's officials, and court suppliers. They reduced the size of the army, and many soldiers became unemployed. Frustrations mounted at court, as the cutbacks spared the regiments under the control of the Guises and their friends.
+
+In religion, the Guises increased the repression of Protestantism started by King Henry II. The autumn of 1559 saw a wave of house searches, arrests, and asset forfeitures.[12] On 23 December 1559, the counsellor-clerk Anne du Bourg, magistrate at the Parlement of Paris, which had contested the repression, was publicly executed in Paris at the Place de Grève.
+
+Determined to stop the persecution and have Protestantism officially recognised, a group of noblemen planned the Amboise conspiracy to overthrow the government and give power to the Princes of the Blood, who supported the new religion. The conspirators planned to take over the palace with the help of the royal guard, abduct the king, then eliminate the Guises if they offered any resistance. A substantial external military deployment was intended to secure the operation.[13] The conspirators also most likely had the secret support of Louis, Prince of Condé, the ambitious younger brother of King Antoine of Navarre.
+
+During February 1560, the court received multiple warnings about the conspiracy. Due to that threat, the royal council decided, under the influence of Queen Catherine de' Medici, to make some concessions. On 8 March 1560, the king signed an edict granting general amnesty to Protestants.[14] But it was too late; the conspiracy was already under way. From all parts of the kingdom, troops were on their way to the Château d'Amboise, where the court was in residence. In the cities of Tours and Orléans, they received money and weapons from the conspirators.
+
+The poorly organised conspiracy ended in a bloodbath. Its outcome was determined as early as 15 March when Jacques, Duke of Nemours, arrested some of the primary conspirators. Over the following days disorientated troops, mostly peasants, were arrested one by one in and around the forest of Amboise. The king was at first inclined to leniency. He freed them and ordered them to return to their homes. But on 17 March, two hundred men tried to storm one of the city gates at the foot of the castle. Quickly repelled by the Duke of Guise, these rebels were unmercifully pursued. More than a hundred were executed, some even hanged from the ramparts of the castle. The retaliation continued for several weeks, and almost twelve hundred people died.
+
+The Guises were less certain how to handle the Prince of Condé. He had arrived at court during the uprising and helped to defend the castle. Interrogation of prisoners clearly placed him as the conspiracy's beneficiary, but the word of commoners did not count against that of a Prince of the Blood. Irrefutable written proof was needed to accuse him. Since he was still free, Condé left the court to meet his brother Antoine in the south-west.[15]
+
+The outburst of violence caused by the Amboise conspiracy made the court decide that persecuting Protestants only made the religious crisis worse. Under the influence of Catherine de Médicis and the members of the royal council, the government tried to ease tensions with a policy of conciliation.[16]
+
+Clemency towards Protestants became policy. Public assemblies were still prohibited, but the government released all religious prisoners. This was the first easing of religious persecution since the reign of Henry II.[17] An edict signed at Romorantin in May 1560 was the beginning of the right to freedom of conscience in France.[18]
+
+In April 1560, the Queen Mother had Michel de l'Hôpital named Lord Chancellor of France. The government was then dominated by "averagers", humanists convinced that reconciliation among Christians was possible, based on reciprocal concessions.[19] Charles, Cardinal of Lorraine, was himself open to church reform. An ecumenical council for the church of France was officially proposed: instead of gaining the consent of Pope Pius IV, the cardinal and the Queen Mother called for a general council in which Christians of all opinions and from all over Europe would meet to reform the religion. The Pope opposed this. Even though they did not want to split from Rome, the Pope's opposition led them to threaten a national council if he did not agree.[20]
+
+To mitigate criticism of the king based on his youth, the government tried to win him approval by communicating his decisions themselves. A gathering of the Estates General was suggested, but, fearing that they would be evicted due to their unpopularity, the Guises strongly opposed this. Under pressure from the Queen Mother, the Guises agreed to consult with the notables: this led to a meeting of the Assembly of Notables at Fontainebleau from 21 to 26 August. The Princes of the Blood and the Constable were asked to attend and to resume their roles in the king's council.[21] During this assembly, the Admiral of Coligny, future head of the Protestants, had a petition from Norman Protestants read before an amazed court that asked for freedom of religion. The assembly closed by convening the Estates General.
+
+Highly critical of the Pope, the Assembly of Notables also decided to gather France's bishops to obtain their consent for a national council. Afraid to see gallicanism slip out of his control, the Pope eventually agreed to a general council, but rejected the attendance of any Protestant, as demanded by the French government.[22] This decision led to the re-opening of the Council of Trent.
+
+The government's conciliation policy was intended to ease tensions, but had the opposite effect. Encouraged by the government's leniency, Protestants continued to congregate for religious services. Although law officials intervened to disperse them and to imprison the organizers, the growing numbers of participants, which sometimes exceeded a thousand, made it impossible to accomplish this for lack of resources. Some were even won over to the new religion. In some places Protestants challenged royal authority with riots and armed rebellions. The unrest that had started sporadically during the Amboise conspiracy spread over the summer throughout the kingdom. The main areas of opposition spanned a crescent-shaped territory from Anjou to Dauphiné and included the regions of Poitou, Guyenne, Périgord, Languedoc, and Provence.
+
+The rioters frequently had the support of local notables. Motivated by fierce propaganda against the Guises, and seeking revenge for the stamping out of the Amboise conspiracy, the boldest attacked castles, jails, and churches. During the spring of 1560, the kingdom experienced the first major events of iconoclasm in Provence.[23] During the summer, the civil disobedience movement gained intensity; several cities in southern France were in revolt.[24][25]
+
+With the secret support of the two Princes of the Blood, Condé and Navarre, a political-military organisation gradually developed. Protestants elected local leaders, raised money, bought weapons, and formed militias. Armed gangs from Languedoc went to Provence and Dauphiné, which Paul de Mouvans and Charles de Montbrun were trying respectively to enlist into the insurrection. The climax came during the night of 4 and 5 September, when Protestant militias tried to take over the city of Lyon.
+
+The king's reaction was fierce and determined: he mobilised his troops, sent the army to the rioting areas, and ordered governors to return to their positions.[26] By autumn, order was slowly restored. Convinced that the Prince of Condé was responsible for the uprising, the king summoned him to court and had him arrested on 31 October 1560.
+
+In foreign policy, Francis II continued peace efforts begun by Henry II with the signing of the Peace of Cateau-Cambrésis in April 1559, which ended 40 years of war between France and the Habsburg empire. At the expense of its influence in Europe, France continued to restore lands conquered over the previous 40 years. In this sense, the reign of Francis II began the decline of French influence throughout Europe, to the benefit of Spain.[27][28]
+
+When King Henry II died, the restitution of these territories was well under way. Francis II, aware of the kingdom's weaknesses, reassured Spain of its intention to fulfill the treaty just signed.[29] The Maréchal de Brissac, who displayed some unwillingness to evacuate Piedmont, was asked to change his behaviour and accelerate the withdrawal.[30][31][32] By the autumn of 1559, France had completely left Savoy, and Piedmont, except for the five locations agreed upon in the Peace of Cateau-Cambrésis. If these were returned to the Duke of Savoy Emmanuel Philibert, Montferrat would be returned to Guglielmo Gonzaga, Duke of Mantua. Both were allies of Spain. Finally, Valenza, which Brissac was grumbling about releasing, was to be returned to the Spanish Duchy of Milan. On the Spanish side, King Philip II showed some unwillingness to return four locations in the north-east of the kingdom as required by the treaty. Border disputes renewed tensions between the two nations, but after months of protests Francis II finally obtained these territories.[33][34]
+
+Along with restitution of territories, the government of Francis II had to negotiate, pay, or claim compensations for people whose properties were taken or destroyed during the war.[35][36] It also had to reach an agreement with Spain regarding the prisoners of war held by both sides. Many noblemen were still prisoners and unable to pay their ransom. Common soldiers were consigned to use as rowers on the royal galleys. Even after a reciprocal release compromise was signed, Spain was not eager to lose its prisoners.[37][38][39]
+
+When Francis II died, France withdrew from Scotland, Brazil, Corsica, Tuscany, Savoy and most of Piedmont.
+
+With the marriage of Francis II and Mary Stuart, the future of Scotland was linked to that of France. A secret clause signed by the queen provided that Scotland would become part of France if the royal couple did not have children.[40] The queen's mother, Marie of Guise, was already regent for Scotland.
+
+Because of French control over their country, a congregation of Scottish lords organised an uprising and made the regent and her French councils leave the capital, Edinburgh, in May 1559. Having taken refuge at the fortress of Dunbar, Marie of Guise asked France for help. Francis II and Mary Stuart sent troops right away. By the end of 1559, France had regained control of Scotland.[41]
+
+Nothing seemed to stand in the way of France controlling Scotland apart from English support for the uprising of the Scottish nobles. Queen Elizabeth I of England was still offended that Francis II and Mary Stuart had put on their coat of arms those of England, thus proclaiming Mary's claims on the throne of England.[42] In January 1560, the English fleet blockaded the port of Leith, which French troops had turned into a military base. They were supported by the arrival in April of 6000 soldiers and 3000 horsemen, which began the siege of the city.
+
+Just as English troops were not particularly successful, the French troops found themselves in a better strategic position. But the poor financial situation of the French government and internal turmoil in the French kingdom prevented any military reinforcements from being sent.[43][44] When the Bishop of Valence and Charles de La Rochefoucault, sieur of Randan, sent by the king to negotiate, arrived in Scotland, they were treated almost like prisoners. With Marie of Guise shut up in an Edinburgh fortress, the two men were forced to negotiate a peace that was disadvantageous to France. On 6 July 1560, they signed the Treaty of Edinburgh, which ended French occupation of Scotland. Francis II and Mary Stuart had to withdraw French troops and stop displaying England's arms.
+
+A few weeks later, Scotland's parliament established Protestantism as the state religion. When Francis II and Mary Stuart were presented with the Treaty of Edinburgh, they were outraged and refused to sign it; they also challenged the legitimacy of the Scottish parliament's decision.[45]
+
+The health of the king deteriorated in November 1560. On 16 November he fainted. After only 17 months on the throne, Francis II died on 5 December 1560 in Orléans, Loiret, from an ear condition. Multiple diseases have been suggested, such as mastoiditis, meningitis, or otitis exacerbated into an abscess. Ambroise Paré, the royal surgeon, considered performing a trepanation. Some suspected Protestants of having poisoned the king, a view held by Catholics as the tensions between them and Protestants were on the rise; however, this has not been proven.
+
+Francis II died childless, so his younger brother Charles, then ten years old, succeeded him. On 21 December, the council named Catherine de Médici as Regent of France. The Guises left the court, while Mary Stuart, Francis II's widow, returned to Scotland. Louis, Prince of Condé, who was jailed and awaiting execution, was freed after some negotiations with Catherine de Médici.
+
+On 23 December 1560, the body of Francis II was interred in the Basilica of Saint-Denis by the Prince of La Roche-sur-Yon.
+
+Francis II had a brief reign. He became king as an inexperienced teenager, at a time when the kingdom was struggling with religious troubles. Historians agree that Francis II was fragile, both physically and psychologically, and his frail health led to his early death.[46] The question of whether his marriage was consummated or not remains unanswered.
+
+Royal arms of Francis, Dauphin and King consort of Scots
+
+Royal arms of Mary, Queen of Scots, impaled with those of Francis
+
+Royal arms of Francis II
+
+Royal arms of Mary, Queen of Scots, Queen consort of France
+
+Royal arms of Mary, Queen of Scots, Queen dowager of France
+

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+Franz Joseph I or Francis Joseph I (German: Franz Josef Karl; 18 August 1830 – 21 November 1916) was Emperor of Austria, King of Hungary, Croatia, and Bohemia, and monarch of other states of the Austro-Hungarian Empire, from 2 December 1848 until his death.[1] From 1 May 1850 to 24 August 1866 he was also President of the German Confederation. He was the longest-reigning ruler of Austria and Hungary, as well as the fourth-longest-reigning monarch of any country in European history.[2]
+
+In December 1848, Emperor Ferdinand abdicated the throne at Olomouc, as part of Minister President Felix zu Schwarzenberg's plan to end the Revolutions of 1848 in Hungary. This allowed Ferdinand's nephew Franz Joseph to accede to the throne. Largely considered to be a reactionary, Franz Joseph spent his early reign resisting constitutionalism in his domains. The Austrian Empire was forced to cede its influence over Tuscany and most of its claim to Lombardy–Venetia to the Kingdom of Piedmont-Sardinia, following the Second Italian War of Independence in 1859 and the Third Italian War of Independence in 1866. Although Franz Joseph ceded no territory to the Kingdom of Prussia after the Austrian defeat in the Austro-Prussian War, the Peace of Prague (23 August 1866) settled the German Question in favour of Prussia, which prevented the Unification of Germany from occurring under the House of Habsburg.[3]
+
+Franz Joseph was troubled by nationalism during his entire reign. He concluded the Austro-Hungarian Compromise of 1867, which granted greater autonomy to Hungary and transformed the Austrian Empire into the Dual Monarchy of Austria-Hungary. He ruled peacefully for the next 45 years, but personally suffered the tragedies of the execution of his brother, the Emperor Maximilian of Mexico in 1867, the suicide of his only son and heir-apparent, Crown Prince Rudolf, in 1889, the assassination of his wife, Empress Elisabeth ("Sisi"), in 1898, and the assassination of his nephew and heir-presumptive, the Archduke Franz Ferdinand, in 1914.
+
+After the Austro-Prussian War, Austria-Hungary turned its attention to the Balkans, which was a hotspot of international tension because of conflicting interests with the Russian Empire. The Bosnian Crisis was a result of Franz Joseph's annexation of Bosnia and Herzegovina in 1908, which had been occupied by his troops since the Congress of Berlin (1878).
+
+On 28 June 1914, the assassination of his nephew and heir-presumptive, Archduke Franz Ferdinand, in Sarajevo resulted in Austria-Hungary's declaration of war against the Kingdom of Serbia, which was an ally of the Russian Empire. That activated a system of alliances which resulted in World War I.
+
+Franz Joseph died on 21 November 1916, after ruling his domains for almost 68 years as one of the longest-reigning monarchs in modern history. He was succeeded by his grandnephew Charles.
+
+Franz Joseph was born in the Schönbrunn Palace in Vienna (on the 65th anniversary of the death of Francis of Lorraine) as the eldest son of Archduke Franz Karl (the younger son of Holy Roman Emperor Francis II), and his wife Princess Sophie of Bavaria. Because his uncle, reigning from 1835 as the Emperor Ferdinand, was weak-minded, and his father unambitious and retiring, the mother of the young Archduke "Franzl" brought him up as a future Emperor, with emphasis on devotion, responsibility and diligence.
+
+Franzl came to idolise his grandfather, der Gute Kaiser Franz, who had died shortly before the former's fifth birthday, as the ideal monarch. At the age of thirteen, Franzl started a career as a colonel in the Austrian army. From that point onward, army style dictated his personal fashion - for the rest of his life he normally wore the uniform of a military officer.[4] Franz Joseph was soon joined by three younger brothers: Archduke Ferdinand Maximilian (born 1832, the future Emperor Maximilian of Mexico); Archduke Karl Ludwig (born 1833, father of Archduke Franz Ferdinand of Austria), and Archduke Ludwig Viktor (born 1842), and a sister, Maria Anna (born 1835), who died at the age of four.[5]
+
+During the Revolutions of 1848 the Austrian Chancellor Prince Metternich resigned (March–April 1848). The young Archduke, who (it was widely expected) would soon succeed his uncle on the throne, was appointed Governor of Bohemia on 6 April 1848, but never took up the post. Sent instead to the front in Italy, he joined Field Marshal Radetzky on campaign on 29 April, receiving his baptism of fire on 5 May at Santa Lucia.
+
+By all accounts he handled his first military experience calmly and with dignity. Around the same time, the Imperial Family was fleeing revolutionary Vienna for the calmer setting of Innsbruck, in Tyrol. Called back from Italy, the Archduke joined the rest of his family at Innsbruck by mid-June. At Innsbruck at this time Franz Joseph first met his cousin Elisabeth, his future bride, then a girl of ten, but apparently the meeting made little impression.[6]
+
+Following Austria's victory over the Italians at Custoza in late July 1848, the court felt it safe to return to Vienna, and Franz Joseph travelled with them. But within a few weeks Vienna again appeared unsafe, and in September the court left once more, this time for Olomouc (Olmütz) in Moravia. By now, Prince Alfred I of Windisch-Grätz, an influential military commander in Bohemia, was determined to see the young Archduke soon put on the throne. It was thought[by whom?] that a new ruler would not be bound by the oaths to respect constitutional government to which Ferdinand had been forced to agree, and that it was necessary to find a young, energetic emperor to replace the kindly, but mentally unfit Ferdinand.[7]
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+By the abdication of his uncle Ferdinand and the renunciation of his father (the mild-mannered Franz Karl) Franz Joseph succeeded as Emperor of Austria at Olomouc on 2 December. At this time he first became known by his second as well as his first Christian name. The name "Franz Joseph" was chosen[by whom?] to bring back memories of the new Emperor's great-granduncle, Emperor Joseph II (Holy Roman Emperor from 1765 to 1790), remembered as a modernising reformer.[8]
+
+Under the guidance of the new prime minister Prince Schwarzenberg the Third, the new emperor at first pursued a cautious course, granting a constitution in early 1849. At the same time, a military campaign was necessary against the Hungarians, who had rebelled against Habsburg central authority in the name of their ancient constitution. Franz Joseph was also almost immediately faced with a renewal of the fighting in Italy, with King Charles Albert of Sardinia taking advantage of setbacks in Hungary to resume the war in March 1849.
+
+However, the military tide began to swiftly turn in favor of Franz Joseph and the Austrian whitecoats. Almost immediately, Charles Albert was decisively beaten by Radetzky at Novara and forced to sue for peace, as well as to renounce his throne.
+
+The crucial turning point of the Hungarian events were the April laws which was ratified by King Ferdinand, however the new young Austrian monarch Francis Joseph arbitrarily "revoked" the laws without any legal competence. This unconstitutional act irreversibly escalated the conflict between the Hungarian parliament and Francis Joseph. The new constrained Stadion Constitution of Austria, the revoke of the April laws and the Austrian military campaign against Kingdom of Hungary resulted in the fall of the pacifist Batthyány government (which sought agreement with the court) and led to the sudden emergence of Lajos Kossuth's followers in the Hungarian parliament, who demanded the full independence of Hungary. The Austrian military intervention in the Kingdom of Hungary resulted in strong anti-Habsburg sentiment among Hungarians, thus the events in Hungary grew into a war for total independence from the Habsburg dynasty.
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+In Hungary, the situation was more severe and Austrian defeat seemed imminent. Sensing a need to secure his right to rule, Franz Joseph sought help from Russia, requesting the intervention of Tsar Nicholas I of Russia, in order "to prevent the Hungarian insurrection developing into a European calamity".[9]
+Tsar Nicholas supported Franz Joseph in the name of the Holy Alliance,[10] and sent a 200,000 strong army with 80,000 auxiliary forces. Finally, the joint army of Russian and Austrian forces defeated the Hungarian forces. After the restoration of Habsburg power, Hungary was placed under brutal martial law.[11]
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+Russian troops entered Hungary in support of the Austrians and the revolution was crushed by late summer of 1849. With order now restored throughout his Empire, Franz Joseph felt free to renege on the constitutional concessions he had made, especially as the Austrian parliament meeting at Kremsier had behaved—in the young Emperor's eyes—abominably. The 1849 constitution was suspended, and a policy of absolutist centralism was established, guided by the Minister of the Interior, Alexander Bach.[12]
+
+On 18 February 1853, Franz Joseph survived an assassination attempt by Hungarian nationalist János Libényi.[13] The emperor was taking a stroll with one of his officers, Count Maximilian Karl Lamoral O'Donnell, on a city bastion, when Libényi approached him. He immediately struck the emperor from behind with a knife straight at the neck. Franz Joseph almost always wore a uniform, which had a high collar that almost completely enclosed the neck. The collars of uniforms at that time were made from very sturdy material, precisely to counter this kind of attack. Even though the Emperor was wounded and bleeding, the collar saved his life. Count O'Donnell struck Libényi down with his sabre.[13]
+
+O'Donnell, hitherto only a Count by virtue of his Irish nobility (as a descendant of the Irish noble dynasty O'Donnell of Tyrconnell),[14] was made a Count of the Habsburg Empire (Reichsgraf). Another witness who happened to be nearby, the butcher Joseph Ettenreich, swiftly overpowered Libényi. For his deed he was later elevated to the nobility by the Emperor and became Joseph von Ettenreich. Libényi was subsequently put on trial and condemned to death for attempted regicide. He was executed on the Simmeringer Heide.[15]
+
+After this unsuccessful attack, the Emperor's brother Archduke Ferdinand Maximilian, later Emperor of Mexico, called upon Europe's royal families for donations to construct a new church on the site of the attack. The church was to be a votive offering for the survival of the Emperor. It is located on Ringstraße in the district of Alsergrund close to the University of Vienna, and is known as the Votivkirche.[13] The survival of Franz Joseph was also commemorated in Prague by erecting a new statue of St. Francis of Assisi, the patron saint of the emperor, on Charles Bridge. It was donated by Count Franz Anton von Kolowrat-Liebsteinsky, the first minister-president of the Austrian Empire.[16]
+
+The next few years saw the seeming recovery of Austria's position on the international scene following the near disasters of 1848–1849. Under Schwarzenberg's guidance, Austria was able to stymie Prussian scheming to create a new German Federation under Prussian leadership, excluding Austria. After Schwarzenberg's premature death in 1852, he could not be replaced by statesmen of equal stature, and the Emperor himself effectively took over as prime minister.[12]
+
+The 1850s witnessed several failures of Austrian external policy: the Crimean War, the dissolution of its alliance with Russia, and defeat in the Second Italian War of Independence. The setbacks continued in the 1860s with defeat in the Austro-Prussian War of 1866, which resulted in the Austro-Hungarian Compromise of 1867.[17]
+
+The Hungarian political leaders had two main goals during the negotiations. One was to regain the traditional status (both legal and political) of the Hungarian state, which was lost after the Hungarian Revolution of 1848. The other was to restore the series of reform laws of the revolutionary parliament of 1848, which were based on the 12 points that established modern civil and political rights, economic and societal reforms in Hungary.[18]
+
+The Compromise partially re-established[19] the sovereignty of the Kingdom of Hungary, separate from, and no longer subject to the Austrian Empire.
+
+The compromise put an end to the 18 years long military dictatorship and absolutist rule over Hungary, which was introduced by Francis Joseph after the Hungarian Revolution of 1848.
+
+According to Emperor Franz Joseph, "There were three of us who made the agreement: Deák, Andrássy and myself."[20]
+
+Political difficulties in Austria mounted continuously through the late 19th century and into the 20th century. However, Franz Joseph remained immensely respected; the Emperor's patriarchal authority held the Empire together while the politicians squabbled among themselves.[21]
+
+Following the accession of Franz Joseph to the throne in 1848, the political representatives of the Kingdom of Bohemia hoped and insisted that account should be taken of their historical state rights in the upcoming constitution. They felt the position of Bohemia within the Habsburg Monarchy should have been highlighted by a coronation of the new ruler to the king of Bohemia in Prague (the last coronation took place in 1836). However before the 19th century the Habsburgs had ruled Bohemia by hereditary right and a separate coronation was not deemed necessary.
+
+His new government installed the system of neoabsolutism in Austrian internal affairs to make the Austrian Empire a unitary, centralised and bureaucratically administered state. When Franz Joseph returned to constitutional rule after the debacles in Italy at Magenta and Solferino and summoned the diets of his lands, the question of his coronation as king of Bohemia again returned to the agenda, as it had not since 1848. On 14 April 1861, Emperor Franz Joseph received a delegation from the Bohemian Diet with his words (in Czech):
+
+"I will have myself crowned King of Bohemia in Prague, and I am convinced that a new, indissoluble bond of trust and loyalty between My throne and My Bohemian Kingdom will be strengthened by this holy rite."[22]
+
+In contrast to his predecessor Emperor Ferdinand (who spent the rest of his life after his abdication in 1848 in Bohemia and especially in Prague), Franz Joseph was never crowned separately as king of Bohemia. In 1861, the negotiations failed because of unsolved constitutional problems. However in 1866, a visit of the monarch to Prague following the defeat at Hradec Králové (Königgrätz) was a huge success, testified by the considerable numbers of new photographs taken.
+
+In 1867, the Austro-Hungarian compromise and the introduction of the dual monarchy left the Czechs and their aristocracy without the recognition of separate Bohemian state rights for which they had hoped. Bohemia remained Austrian Crown Lands. In Bohemia, opposition to dualism took the form of isolated street demonstrations, resolutions from district representations, and even open air mass protest meetings, confined to the biggest cities, such as Prague. The Czech newspaper Národní listy, complained that the Czechs had not yet been compensated for their wartime losses and sufferings during the Austro-Prussian War, and had just seen their historic state rights tossed aside and their land subsumed into the "other" half of the Austro-Hungarian Monarchy, commonly called "Cisleithania".[22]
+
+The Czech hopes were revived again in 1870–1871. In an Imperial Rescript of 26 September 1870, Franz Joseph referred again to the prestige and glory of the Bohemian Crown and to his intention to hold a coronation. Under Minister-President Karl Hohenwart in 1871, the government of Cisleithania negotiated a series of fundamental articles spelling out the relationship of the Bohemian Crown to the rest of the Habsburg Monarchy. On 12 September 1871, Franz Joseph announced:
+
+Having in mind the constitutional position of the Bohemian Crown and being conscious of the glory and power which that Crown has given us 'and our predecessors… we gladly recognise the rights of the kingdom and are prepared to renew that recognition through our coronation oath.[22]
+
+For the planned coronation, the composer Bedřich Smetana had written the opera Libuše, but the ceremony did not take place. The creation of the German Empire, domestic opposition from German-speaking liberals (especially German-Bohemians) and from Hungarians doomed the Fundamental Articles. Hohenwart resigned and nothing changed.
+
+Many Czech people were waiting for political changes in monarchy, including Tomáš Garrigue Masaryk and others. Masaryk served in the Reichsrat (Upper House) from 1891 to 1893 in the Young Czech Party and again from 1907 to 1914 in the Realist Party (which he had founded in 1900), but he did not campaign for the independence of Czechs and Slovaks from Austria-Hungary. In Vienna in 1909 he helped Hinko Hinković's defense in the fabricated trial against prominent Croats and Serbs members of the Serbo-Croatian Coalition (such as Frano Supilo and Svetozar Pribićević), and others, who were sentenced to more than 150 years and a number of death penalties. The Bohemian question would remain unresolved for the entirety of Franz Joseph's reign.
+
+The main foreign policy goal of Franz Joseph had been the unification of Germany under the House of Habsburg.[23] This was justified on grounds of precedence; from 1452 to the end of the Holy Roman Empire in 1806, with only one period of interruption under the Wittelsbachs, the Habsburgs had generally held the German crown.[24] However, Franz Joseph's desire to retain the non-German territories of the Habsburg Austrian Empire in the event of German unification proved problematic.
+
+Two factions quickly developed: a party of German intellectuals favouring a Greater Germany (Großdeutschland) under the House of Habsburg; the other favouring a Lesser Germany (Kleindeutschland). The Greater Germans favoured the inclusion of Austria in a new all-German state on the grounds that Austria had always been a part of Germanic empires, that it was the leading power of the German Confederation, and that it would be absurd to exclude eight million Austrian Germans from an all-German nation state. The champions of a lesser Germany argued against the inclusion of Austria on the grounds that it was a multi-nation state, not a German one, and that its inclusion would bring millions of non-Germans into the German nation state.[25]
+
+If Greater Germany were to prevail, the crown would necessarily have to go to Franz Joseph, who had no desire to cede it in the first place to anyone else.[25] On the other hand, if the idea of a smaller Germany won out, the German crown could of course not possibly go to the Emperor of Austria, but would naturally be offered to the head of the largest and most powerful German state outside of Austria—the King of Prussia. The contest between the two ideas, quickly developed into a contest between Austria and Prussia. After Prussia decisively won the Seven Weeks War, this question was solved; Austria lost no territories to Prussia as long as they remained out of German affairs.[25]
+
+Franz Joseph's German identity was made explicitly clear during a meeting in August 1908 between himself and Edward VII when the latter tried to persuade him to abandon Austria-Hungary's alliance with Germany for co-operation with England; Franz Joseph replied that he was a "loyal ally" and said "I am a German prince."[26][27]
+
+In 1873, two years after the unification of Germany, Franz Joseph entered into the League of Three Emperors (Dreikaiserbund) with Kaiser Wilhelm I of Germany and Tsar Alexander II of Russia, who was succeeded by Tsar Alexander III in 1881. The league had been designed by the German chancellor Otto von Bismarck, as an attempt to maintain the peace of Europe. It would last intermittently until 1887.
+
+In 1903, Franz Joseph's veto of Cardinal Mariano Rampolla's election to the papacy was transmitted to the Papal conclave by Cardinal Jan Puzyna de Kosielsko. It was the last use of such a veto, as the new Pope Pius X prohibited future uses and provided for excommunication for any attempt.[28][29]
+
+During the mid-1870s a series of violent rebellions against Ottoman rule broke out in the Balkans, and the Turks responded with equally violent and oppressive reprisals. Tsar Alexander II of Russia, wanting to intervene against the Ottomans, sought and obtained an agreement with Austria-Hungary.
+
+In the Budapest Conventions of 1877, the two powers agreed that Russia would annex Bessarabia, and Austria-Hungary would observe a benevolent neutrality toward Russia in the pending war with the Turks. As compensation for this support, Russia agreed to Austria-Hungary's annexation of Bosnia-Herzegovina.[30] A scant 15 months later, the Russians imposed on the Ottomans the Treaty of San Stefano, which reneged on the Budapest accord and declared that Bosnia-Herzegovina would be jointly occupied by Russian and Austrian troops.[30]
+
+The treaty was overturned by the 1878 Treaty of Berlin, which allowed sole Austrian occupation of Bosnia-Herzegovina but did not specify a final disposition of the provinces.[clarification needed] That omission was addressed in the Three Emperors' League agreement of 1881, when both Germany and Russia endorsed Austria's right to annex Bosnia-Herzegovina.[31] However, by 1897, under a new tsar, the Russian Imperial government had again withdrawn its support for Austrian annexation of Bosnia-Herzegovina. The Russian foreign minister, Count Michael Muraviev, stated that an Austrian annexation of Bosnia-Herzegovina would raise "an extensive question requiring special scrutiny".[32]
+
+In 1908, the Russian foreign minister, Alexander Izvolsky, offered Russian support, for the third time, for the annexation of Bosnia and Herzegovina by Austria-Hungary, in exchange for Austrian support for the opening of the Bosporus Strait and the Dardanelles to Russian warships. Austria's foreign minister, Alois von Aehrenthal, pursued this offer vigorously, resulting in the quid pro quo understanding with Izvolsky, reached on 16 September 1908 at the Buchlau Conference. However, Izvolsky made this agreement with Aehrenthal without the knowledge of Tsar Nicholas II or his government in St. Petersburg, or any of the other foreign powers including Britain, France and Serbia.
+
+Based upon the assurances of the Buchlau Conference and the treaties that preceded it, Franz Joseph signed the proclamation announcing the annexation of Bosnia-Herzegovina into the Empire on 6 October 1908. However a diplomatic crisis erupted, as both the Serbs and the Italians demanded compensation for the annexation, which the Austro-Hungarian government refused to entertain. The incident was not resolved until the revision of the Treaty of Berlin in April 1909, exacerbating tensions between Austria-Hungary and the Serbs.
+
+On 28 June 1914 Franz Joseph's nephew and heir Archduke Franz Ferdinand, and his morganatic wife Sophie, Duchess of Hohenberg, were assassinated by Gavrilo Princip, a Yugoslav nationalist of Serbian ethnicity,[33] during a visit to Sarajevo. When he heard the news of the assassination, Franz Joseph said that "one has not to defy the Almighty. In this manner a superior power has restored that order which I unfortunately was unable to maintain."[34]
+
+While the emperor was shaken, and interrupted his holiday to return to Vienna, he soon resumed his vacation at his imperial villa at Bad Ischl. Initial decision-making during the "July Crisis" fell to Count Leopold Berchtold, the Austrian foreign minister; Count Franz Conrad von Hötzendorf, the chief of staff for the Austro-Hungarian army and the other ministers.[35] The ultimate resolution of deliberations by the Austrian government during the weeks following the assassination of the Archduke was to give Serbia an ultimatum of itemized demands with which it was virtually certain Serbia would be unable or unwilling to comply, thus serving as a "legal basis for war."
+
+However, the general movement toward war with Serbia was already in motion prior to assassination of the Archduke as evidenced by a 14 June memo of Berchtold recommending the "elimination of Serbia" as a state, which Franz Joseph expressed agreement with in a letter delivered to Kaiser Wilhelm II in Berlin on 5 July. In that letter, Franz Joseph "...explicitly stated that the decision for war against Serbia had been made before the assassination of the Archduke, and that the events of Sarajevo only confirmed the already pre-existing need for a war."
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+A week after delivery of the Austrian ultimatum to Serbia, on 28 July, Austria-Hungary declared war on Serbia. Within weeks, the Germans, Russians, French and British had all entered the fray which eventually became known as World War I. On 6 August, Franz Joseph signed the declaration of war against Russia.
+
+Franz Joseph died in the Schönbrunn Palace on the evening of 21 November 1916, at the age of 86. His death was a result of developing pneumonia of the right lung several days after catching a cold while walking in Schönbrunn Park with the King of Bavaria.[36] He was succeeded by his grandnephew Charles I, who reigned until the collapse of the Empire following its defeat in 1918.[37]
+
+He is buried in the Imperial Crypt in Vienna, where flowers are still left by monarchists.[citation needed]
+
+It was generally felt in the court that the Emperor should marry and produce heirs as soon as possible. Various potential brides were considered, including Princess Elisabeth of Modena, Princess Anna of Prussia and Princess Sidonia of Saxony.[38] Although in public life Franz Joseph was the unquestioned director of affairs, in his private life his mother still wielded crucial influence. Sophie wanted to strengthen the relationship between the Houses of Habsburg and Wittelsbach—descending from the latter house herself—and hoped to match Franz Joseph with her sister Ludovika's eldest daughter, Helene ("Néné"), who was four years the Emperor's junior.
+
+However, Franz Joseph fell deeply in love with Néné's younger sister Elisabeth ("Sisi"), a beautiful girl of fifteen, and insisted on marrying her instead. Sophie acquiesced, despite her misgivings about Sisi's appropriateness as an imperial consort, and the young couple were married on 24 April 1854 in St. Augustine's Church, Vienna.[39]
+
+Their marriage would eventually prove to be an unhappy one; though Franz Joseph was passionately in love with his wife, the feeling was not mutual. Elisabeth never truly acclimatized to life at court, and was frequently in conflict with the imperial family. Their first daughter Sophie died as an infant, and their only son Rudolf died by suicide in 1889 in the infamous Mayerling Incident.[28]
+
+In 1885 Franz Joseph met Katharina Schratt, a leading actress of the Vienna stage, and she became his friend and confidante. This relationship lasted the rest of his life, and was—to a certain degree—tolerated by Elisabeth. Franz Joseph built Villa Schratt in Bad Ischl for her, and also provided her with a small palace in Vienna.[40] Though their relationship lasted for thirty-four years, it remained platonic.[41]
+
+The Empress was an inveterate traveller, horsewoman, and fashion maven who was rarely seen in Vienna. Sisi was obsessed about preserving her beauty, carrying out many bizarre routines and strenuous exercise, and as a result suffered from ill health. She was stabbed to death by an Italian anarchist in 1898 while on a visit to Geneva. A few days after the funeral, Robert of Parma wrote in a letter to his friend Tirso de Olazábal that "It was pitiful to look at the Emperor, he showed a great deal of energy in his immense pain, but at times one could see all the immensity of his grief."[42] Franz Joseph never fully recovered from the loss. According to the future empress Zita of Bourbon-Parma he told his relatives: "You'll never know how important she was to me" or, according to some sources, "You will never know how much I loved this woman."[43]
+
+Archduke Franz Ferdinand became heir presumptive (Thronfolger) to the throne of Austria-Hungary in 1896, after the deaths of his cousin Rudolf (in 1889) and his father Karl Ludwig (in 1896). The relationship between him and Franz Joseph had always been a fairly contentious one, which was further exacerbated when Franz Ferdinand announced his desire to marry Countess Sophie Chotek, a match that was out of the question in the mind of the emperor, as Sophie was merely of nobility as opposed to being of dynastic rank.
+
+Although the emperor received letters from members of the imperial family throughout the fall and winter of 1899 importuning him to relent, Franz Joseph stood his ground.[44] He finally gave his consent in 1900; however, the marriage was to be morganatic, and any children of the marriage would be ineligible to succeed to the throne.[45] The couple were married on 1 July 1900 at Reichstadt. The emperor did not attend the wedding, nor did any of the archdukes. After that, the two men disliked and distrusted each other.[40]
+
+Following the assassination of Franz Ferdinand and Sophie in 1914, Franz Joseph's daughter, Marie Valerie, noted that her father expressed his greater confidence in the new heir presumptive: his grandnephew Archduke Charles. The emperor admitted to his daughter, regarding the assassination: "For me, it is a relief from a great worry."[46]
+
+Franz Joseph's names in the languages of his empire were:
+
+His official grand title after the Ausgleich of 1867 was: "Francis Joseph the First, by the Grace of God Emperor of Austria, Apostolic King of Hungary, King of Bohemia, King of Dalmatia, Croatia, Slavonia, Galicia and Lodomeria and Illyria; King of Jerusalem etc., Archduke of Austria; Grand Duke of Tuscany and Cracow, Duke of Lorraine, of Salzburg, Styria, Carinthia, Carniola and of Bukovina; Grand Prince of Transylvania; Margrave of Moravia; Duke of Upper and Lower Silesia, of Modena, Parma, Piacenza and Guastalla, of Oświęcim, Zator and Ćeszyn, Friuli, Ragusa (Dubrovnik) and Zara (Zadar); Princely Count of Habsburg and Tyrol, of Kyburg, Gorizia and Gradisca; Prince of Trent (Trento) and Brixen; Margrave of Upper and Lower Lusatia and in Istria; Count of Hohenems, Feldkirch, Bregenz, Sonnenberg, etc.; Lord of Trieste, of Cattaro (Kotor), and over the Windic march; Grand Voivode of the Voivodship of Serbia."[48]
+
+In addition, he founded the Order of Franz Joseph (Franz Joseph-Orden) on 2 December 1849,[55] and the Order of Elizabeth (Elizabeth-Orden) in 1898.[56]
+
+Franz Joseph Land in the Russian Arctic was named in his honour in 1873 by the Austro-Hungarian North Pole expedition which first reported finding it. The Franz Joseph Glacier in New Zealand's South Island also bears his name.
+
+Franz Joseph founded in 1872 the Franz Joseph University (Hungarian: Ferenc József Tudományegyetem, Romanian: Universitatea Francisc Iosif) in the city of Cluj-Napoca (at that time a part of Austria-Hungary under the name of Kolozsvár). The university was moved to Szeged after Cluj became a part of Romania, becoming the University of Szeged.
+
+In certain areas, celebrations are still being held in remembrance of Franz Joseph's birthday. The Mitteleuropean People's Festival takes place every year around 18 August, and is a "spontaneous, traditional and brotherly meeting among peoples of the Central-European Countries".[97] The event includes ceremonies, meetings, music, songs, dances, wine and food tasting, and traditional costumes and folklore from Mitteleuropa.

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+Franz Joseph I or Francis Joseph I (German: Franz Josef Karl; 18 August 1830 – 21 November 1916) was Emperor of Austria, King of Hungary, Croatia, and Bohemia, and monarch of other states of the Austro-Hungarian Empire, from 2 December 1848 until his death.[1] From 1 May 1850 to 24 August 1866 he was also President of the German Confederation. He was the longest-reigning ruler of Austria and Hungary, as well as the fourth-longest-reigning monarch of any country in European history.[2]
+
+In December 1848, Emperor Ferdinand abdicated the throne at Olomouc, as part of Minister President Felix zu Schwarzenberg's plan to end the Revolutions of 1848 in Hungary. This allowed Ferdinand's nephew Franz Joseph to accede to the throne. Largely considered to be a reactionary, Franz Joseph spent his early reign resisting constitutionalism in his domains. The Austrian Empire was forced to cede its influence over Tuscany and most of its claim to Lombardy–Venetia to the Kingdom of Piedmont-Sardinia, following the Second Italian War of Independence in 1859 and the Third Italian War of Independence in 1866. Although Franz Joseph ceded no territory to the Kingdom of Prussia after the Austrian defeat in the Austro-Prussian War, the Peace of Prague (23 August 1866) settled the German Question in favour of Prussia, which prevented the Unification of Germany from occurring under the House of Habsburg.[3]
+
+Franz Joseph was troubled by nationalism during his entire reign. He concluded the Austro-Hungarian Compromise of 1867, which granted greater autonomy to Hungary and transformed the Austrian Empire into the Dual Monarchy of Austria-Hungary. He ruled peacefully for the next 45 years, but personally suffered the tragedies of the execution of his brother, the Emperor Maximilian of Mexico in 1867, the suicide of his only son and heir-apparent, Crown Prince Rudolf, in 1889, the assassination of his wife, Empress Elisabeth ("Sisi"), in 1898, and the assassination of his nephew and heir-presumptive, the Archduke Franz Ferdinand, in 1914.
+
+After the Austro-Prussian War, Austria-Hungary turned its attention to the Balkans, which was a hotspot of international tension because of conflicting interests with the Russian Empire. The Bosnian Crisis was a result of Franz Joseph's annexation of Bosnia and Herzegovina in 1908, which had been occupied by his troops since the Congress of Berlin (1878).
+
+On 28 June 1914, the assassination of his nephew and heir-presumptive, Archduke Franz Ferdinand, in Sarajevo resulted in Austria-Hungary's declaration of war against the Kingdom of Serbia, which was an ally of the Russian Empire. That activated a system of alliances which resulted in World War I.
+
+Franz Joseph died on 21 November 1916, after ruling his domains for almost 68 years as one of the longest-reigning monarchs in modern history. He was succeeded by his grandnephew Charles.
+
+Franz Joseph was born in the Schönbrunn Palace in Vienna (on the 65th anniversary of the death of Francis of Lorraine) as the eldest son of Archduke Franz Karl (the younger son of Holy Roman Emperor Francis II), and his wife Princess Sophie of Bavaria. Because his uncle, reigning from 1835 as the Emperor Ferdinand, was weak-minded, and his father unambitious and retiring, the mother of the young Archduke "Franzl" brought him up as a future Emperor, with emphasis on devotion, responsibility and diligence.
+
+Franzl came to idolise his grandfather, der Gute Kaiser Franz, who had died shortly before the former's fifth birthday, as the ideal monarch. At the age of thirteen, Franzl started a career as a colonel in the Austrian army. From that point onward, army style dictated his personal fashion - for the rest of his life he normally wore the uniform of a military officer.[4] Franz Joseph was soon joined by three younger brothers: Archduke Ferdinand Maximilian (born 1832, the future Emperor Maximilian of Mexico); Archduke Karl Ludwig (born 1833, father of Archduke Franz Ferdinand of Austria), and Archduke Ludwig Viktor (born 1842), and a sister, Maria Anna (born 1835), who died at the age of four.[5]
+
+During the Revolutions of 1848 the Austrian Chancellor Prince Metternich resigned (March–April 1848). The young Archduke, who (it was widely expected) would soon succeed his uncle on the throne, was appointed Governor of Bohemia on 6 April 1848, but never took up the post. Sent instead to the front in Italy, he joined Field Marshal Radetzky on campaign on 29 April, receiving his baptism of fire on 5 May at Santa Lucia.
+
+By all accounts he handled his first military experience calmly and with dignity. Around the same time, the Imperial Family was fleeing revolutionary Vienna for the calmer setting of Innsbruck, in Tyrol. Called back from Italy, the Archduke joined the rest of his family at Innsbruck by mid-June. At Innsbruck at this time Franz Joseph first met his cousin Elisabeth, his future bride, then a girl of ten, but apparently the meeting made little impression.[6]
+
+Following Austria's victory over the Italians at Custoza in late July 1848, the court felt it safe to return to Vienna, and Franz Joseph travelled with them. But within a few weeks Vienna again appeared unsafe, and in September the court left once more, this time for Olomouc (Olmütz) in Moravia. By now, Prince Alfred I of Windisch-Grätz, an influential military commander in Bohemia, was determined to see the young Archduke soon put on the throne. It was thought[by whom?] that a new ruler would not be bound by the oaths to respect constitutional government to which Ferdinand had been forced to agree, and that it was necessary to find a young, energetic emperor to replace the kindly, but mentally unfit Ferdinand.[7]
+
+By the abdication of his uncle Ferdinand and the renunciation of his father (the mild-mannered Franz Karl) Franz Joseph succeeded as Emperor of Austria at Olomouc on 2 December. At this time he first became known by his second as well as his first Christian name. The name "Franz Joseph" was chosen[by whom?] to bring back memories of the new Emperor's great-granduncle, Emperor Joseph II (Holy Roman Emperor from 1765 to 1790), remembered as a modernising reformer.[8]
+
+Under the guidance of the new prime minister Prince Schwarzenberg the Third, the new emperor at first pursued a cautious course, granting a constitution in early 1849. At the same time, a military campaign was necessary against the Hungarians, who had rebelled against Habsburg central authority in the name of their ancient constitution. Franz Joseph was also almost immediately faced with a renewal of the fighting in Italy, with King Charles Albert of Sardinia taking advantage of setbacks in Hungary to resume the war in March 1849.
+
+However, the military tide began to swiftly turn in favor of Franz Joseph and the Austrian whitecoats. Almost immediately, Charles Albert was decisively beaten by Radetzky at Novara and forced to sue for peace, as well as to renounce his throne.
+
+The crucial turning point of the Hungarian events were the April laws which was ratified by King Ferdinand, however the new young Austrian monarch Francis Joseph arbitrarily "revoked" the laws without any legal competence. This unconstitutional act irreversibly escalated the conflict between the Hungarian parliament and Francis Joseph. The new constrained Stadion Constitution of Austria, the revoke of the April laws and the Austrian military campaign against Kingdom of Hungary resulted in the fall of the pacifist Batthyány government (which sought agreement with the court) and led to the sudden emergence of Lajos Kossuth's followers in the Hungarian parliament, who demanded the full independence of Hungary. The Austrian military intervention in the Kingdom of Hungary resulted in strong anti-Habsburg sentiment among Hungarians, thus the events in Hungary grew into a war for total independence from the Habsburg dynasty.
+
+In Hungary, the situation was more severe and Austrian defeat seemed imminent. Sensing a need to secure his right to rule, Franz Joseph sought help from Russia, requesting the intervention of Tsar Nicholas I of Russia, in order "to prevent the Hungarian insurrection developing into a European calamity".[9]
+Tsar Nicholas supported Franz Joseph in the name of the Holy Alliance,[10] and sent a 200,000 strong army with 80,000 auxiliary forces. Finally, the joint army of Russian and Austrian forces defeated the Hungarian forces. After the restoration of Habsburg power, Hungary was placed under brutal martial law.[11]
+
+Russian troops entered Hungary in support of the Austrians and the revolution was crushed by late summer of 1849. With order now restored throughout his Empire, Franz Joseph felt free to renege on the constitutional concessions he had made, especially as the Austrian parliament meeting at Kremsier had behaved—in the young Emperor's eyes—abominably. The 1849 constitution was suspended, and a policy of absolutist centralism was established, guided by the Minister of the Interior, Alexander Bach.[12]
+
+On 18 February 1853, Franz Joseph survived an assassination attempt by Hungarian nationalist János Libényi.[13] The emperor was taking a stroll with one of his officers, Count Maximilian Karl Lamoral O'Donnell, on a city bastion, when Libényi approached him. He immediately struck the emperor from behind with a knife straight at the neck. Franz Joseph almost always wore a uniform, which had a high collar that almost completely enclosed the neck. The collars of uniforms at that time were made from very sturdy material, precisely to counter this kind of attack. Even though the Emperor was wounded and bleeding, the collar saved his life. Count O'Donnell struck Libényi down with his sabre.[13]
+
+O'Donnell, hitherto only a Count by virtue of his Irish nobility (as a descendant of the Irish noble dynasty O'Donnell of Tyrconnell),[14] was made a Count of the Habsburg Empire (Reichsgraf). Another witness who happened to be nearby, the butcher Joseph Ettenreich, swiftly overpowered Libényi. For his deed he was later elevated to the nobility by the Emperor and became Joseph von Ettenreich. Libényi was subsequently put on trial and condemned to death for attempted regicide. He was executed on the Simmeringer Heide.[15]
+
+After this unsuccessful attack, the Emperor's brother Archduke Ferdinand Maximilian, later Emperor of Mexico, called upon Europe's royal families for donations to construct a new church on the site of the attack. The church was to be a votive offering for the survival of the Emperor. It is located on Ringstraße in the district of Alsergrund close to the University of Vienna, and is known as the Votivkirche.[13] The survival of Franz Joseph was also commemorated in Prague by erecting a new statue of St. Francis of Assisi, the patron saint of the emperor, on Charles Bridge. It was donated by Count Franz Anton von Kolowrat-Liebsteinsky, the first minister-president of the Austrian Empire.[16]
+
+The next few years saw the seeming recovery of Austria's position on the international scene following the near disasters of 1848–1849. Under Schwarzenberg's guidance, Austria was able to stymie Prussian scheming to create a new German Federation under Prussian leadership, excluding Austria. After Schwarzenberg's premature death in 1852, he could not be replaced by statesmen of equal stature, and the Emperor himself effectively took over as prime minister.[12]
+
+The 1850s witnessed several failures of Austrian external policy: the Crimean War, the dissolution of its alliance with Russia, and defeat in the Second Italian War of Independence. The setbacks continued in the 1860s with defeat in the Austro-Prussian War of 1866, which resulted in the Austro-Hungarian Compromise of 1867.[17]
+
+The Hungarian political leaders had two main goals during the negotiations. One was to regain the traditional status (both legal and political) of the Hungarian state, which was lost after the Hungarian Revolution of 1848. The other was to restore the series of reform laws of the revolutionary parliament of 1848, which were based on the 12 points that established modern civil and political rights, economic and societal reforms in Hungary.[18]
+
+The Compromise partially re-established[19] the sovereignty of the Kingdom of Hungary, separate from, and no longer subject to the Austrian Empire.
+
+The compromise put an end to the 18 years long military dictatorship and absolutist rule over Hungary, which was introduced by Francis Joseph after the Hungarian Revolution of 1848.
+
+According to Emperor Franz Joseph, "There were three of us who made the agreement: Deák, Andrássy and myself."[20]
+
+Political difficulties in Austria mounted continuously through the late 19th century and into the 20th century. However, Franz Joseph remained immensely respected; the Emperor's patriarchal authority held the Empire together while the politicians squabbled among themselves.[21]
+
+Following the accession of Franz Joseph to the throne in 1848, the political representatives of the Kingdom of Bohemia hoped and insisted that account should be taken of their historical state rights in the upcoming constitution. They felt the position of Bohemia within the Habsburg Monarchy should have been highlighted by a coronation of the new ruler to the king of Bohemia in Prague (the last coronation took place in 1836). However before the 19th century the Habsburgs had ruled Bohemia by hereditary right and a separate coronation was not deemed necessary.
+
+His new government installed the system of neoabsolutism in Austrian internal affairs to make the Austrian Empire a unitary, centralised and bureaucratically administered state. When Franz Joseph returned to constitutional rule after the debacles in Italy at Magenta and Solferino and summoned the diets of his lands, the question of his coronation as king of Bohemia again returned to the agenda, as it had not since 1848. On 14 April 1861, Emperor Franz Joseph received a delegation from the Bohemian Diet with his words (in Czech):
+
+"I will have myself crowned King of Bohemia in Prague, and I am convinced that a new, indissoluble bond of trust and loyalty between My throne and My Bohemian Kingdom will be strengthened by this holy rite."[22]
+
+In contrast to his predecessor Emperor Ferdinand (who spent the rest of his life after his abdication in 1848 in Bohemia and especially in Prague), Franz Joseph was never crowned separately as king of Bohemia. In 1861, the negotiations failed because of unsolved constitutional problems. However in 1866, a visit of the monarch to Prague following the defeat at Hradec Králové (Königgrätz) was a huge success, testified by the considerable numbers of new photographs taken.
+
+In 1867, the Austro-Hungarian compromise and the introduction of the dual monarchy left the Czechs and their aristocracy without the recognition of separate Bohemian state rights for which they had hoped. Bohemia remained Austrian Crown Lands. In Bohemia, opposition to dualism took the form of isolated street demonstrations, resolutions from district representations, and even open air mass protest meetings, confined to the biggest cities, such as Prague. The Czech newspaper Národní listy, complained that the Czechs had not yet been compensated for their wartime losses and sufferings during the Austro-Prussian War, and had just seen their historic state rights tossed aside and their land subsumed into the "other" half of the Austro-Hungarian Monarchy, commonly called "Cisleithania".[22]
+
+The Czech hopes were revived again in 1870–1871. In an Imperial Rescript of 26 September 1870, Franz Joseph referred again to the prestige and glory of the Bohemian Crown and to his intention to hold a coronation. Under Minister-President Karl Hohenwart in 1871, the government of Cisleithania negotiated a series of fundamental articles spelling out the relationship of the Bohemian Crown to the rest of the Habsburg Monarchy. On 12 September 1871, Franz Joseph announced:
+
+Having in mind the constitutional position of the Bohemian Crown and being conscious of the glory and power which that Crown has given us 'and our predecessors… we gladly recognise the rights of the kingdom and are prepared to renew that recognition through our coronation oath.[22]
+
+For the planned coronation, the composer Bedřich Smetana had written the opera Libuše, but the ceremony did not take place. The creation of the German Empire, domestic opposition from German-speaking liberals (especially German-Bohemians) and from Hungarians doomed the Fundamental Articles. Hohenwart resigned and nothing changed.
+
+Many Czech people were waiting for political changes in monarchy, including Tomáš Garrigue Masaryk and others. Masaryk served in the Reichsrat (Upper House) from 1891 to 1893 in the Young Czech Party and again from 1907 to 1914 in the Realist Party (which he had founded in 1900), but he did not campaign for the independence of Czechs and Slovaks from Austria-Hungary. In Vienna in 1909 he helped Hinko Hinković's defense in the fabricated trial against prominent Croats and Serbs members of the Serbo-Croatian Coalition (such as Frano Supilo and Svetozar Pribićević), and others, who were sentenced to more than 150 years and a number of death penalties. The Bohemian question would remain unresolved for the entirety of Franz Joseph's reign.
+
+The main foreign policy goal of Franz Joseph had been the unification of Germany under the House of Habsburg.[23] This was justified on grounds of precedence; from 1452 to the end of the Holy Roman Empire in 1806, with only one period of interruption under the Wittelsbachs, the Habsburgs had generally held the German crown.[24] However, Franz Joseph's desire to retain the non-German territories of the Habsburg Austrian Empire in the event of German unification proved problematic.
+
+Two factions quickly developed: a party of German intellectuals favouring a Greater Germany (Großdeutschland) under the House of Habsburg; the other favouring a Lesser Germany (Kleindeutschland). The Greater Germans favoured the inclusion of Austria in a new all-German state on the grounds that Austria had always been a part of Germanic empires, that it was the leading power of the German Confederation, and that it would be absurd to exclude eight million Austrian Germans from an all-German nation state. The champions of a lesser Germany argued against the inclusion of Austria on the grounds that it was a multi-nation state, not a German one, and that its inclusion would bring millions of non-Germans into the German nation state.[25]
+
+If Greater Germany were to prevail, the crown would necessarily have to go to Franz Joseph, who had no desire to cede it in the first place to anyone else.[25] On the other hand, if the idea of a smaller Germany won out, the German crown could of course not possibly go to the Emperor of Austria, but would naturally be offered to the head of the largest and most powerful German state outside of Austria—the King of Prussia. The contest between the two ideas, quickly developed into a contest between Austria and Prussia. After Prussia decisively won the Seven Weeks War, this question was solved; Austria lost no territories to Prussia as long as they remained out of German affairs.[25]
+
+Franz Joseph's German identity was made explicitly clear during a meeting in August 1908 between himself and Edward VII when the latter tried to persuade him to abandon Austria-Hungary's alliance with Germany for co-operation with England; Franz Joseph replied that he was a "loyal ally" and said "I am a German prince."[26][27]
+
+In 1873, two years after the unification of Germany, Franz Joseph entered into the League of Three Emperors (Dreikaiserbund) with Kaiser Wilhelm I of Germany and Tsar Alexander II of Russia, who was succeeded by Tsar Alexander III in 1881. The league had been designed by the German chancellor Otto von Bismarck, as an attempt to maintain the peace of Europe. It would last intermittently until 1887.
+
+In 1903, Franz Joseph's veto of Cardinal Mariano Rampolla's election to the papacy was transmitted to the Papal conclave by Cardinal Jan Puzyna de Kosielsko. It was the last use of such a veto, as the new Pope Pius X prohibited future uses and provided for excommunication for any attempt.[28][29]
+
+During the mid-1870s a series of violent rebellions against Ottoman rule broke out in the Balkans, and the Turks responded with equally violent and oppressive reprisals. Tsar Alexander II of Russia, wanting to intervene against the Ottomans, sought and obtained an agreement with Austria-Hungary.
+
+In the Budapest Conventions of 1877, the two powers agreed that Russia would annex Bessarabia, and Austria-Hungary would observe a benevolent neutrality toward Russia in the pending war with the Turks. As compensation for this support, Russia agreed to Austria-Hungary's annexation of Bosnia-Herzegovina.[30] A scant 15 months later, the Russians imposed on the Ottomans the Treaty of San Stefano, which reneged on the Budapest accord and declared that Bosnia-Herzegovina would be jointly occupied by Russian and Austrian troops.[30]
+
+The treaty was overturned by the 1878 Treaty of Berlin, which allowed sole Austrian occupation of Bosnia-Herzegovina but did not specify a final disposition of the provinces.[clarification needed] That omission was addressed in the Three Emperors' League agreement of 1881, when both Germany and Russia endorsed Austria's right to annex Bosnia-Herzegovina.[31] However, by 1897, under a new tsar, the Russian Imperial government had again withdrawn its support for Austrian annexation of Bosnia-Herzegovina. The Russian foreign minister, Count Michael Muraviev, stated that an Austrian annexation of Bosnia-Herzegovina would raise "an extensive question requiring special scrutiny".[32]
+
+In 1908, the Russian foreign minister, Alexander Izvolsky, offered Russian support, for the third time, for the annexation of Bosnia and Herzegovina by Austria-Hungary, in exchange for Austrian support for the opening of the Bosporus Strait and the Dardanelles to Russian warships. Austria's foreign minister, Alois von Aehrenthal, pursued this offer vigorously, resulting in the quid pro quo understanding with Izvolsky, reached on 16 September 1908 at the Buchlau Conference. However, Izvolsky made this agreement with Aehrenthal without the knowledge of Tsar Nicholas II or his government in St. Petersburg, or any of the other foreign powers including Britain, France and Serbia.
+
+Based upon the assurances of the Buchlau Conference and the treaties that preceded it, Franz Joseph signed the proclamation announcing the annexation of Bosnia-Herzegovina into the Empire on 6 October 1908. However a diplomatic crisis erupted, as both the Serbs and the Italians demanded compensation for the annexation, which the Austro-Hungarian government refused to entertain. The incident was not resolved until the revision of the Treaty of Berlin in April 1909, exacerbating tensions between Austria-Hungary and the Serbs.
+
+On 28 June 1914 Franz Joseph's nephew and heir Archduke Franz Ferdinand, and his morganatic wife Sophie, Duchess of Hohenberg, were assassinated by Gavrilo Princip, a Yugoslav nationalist of Serbian ethnicity,[33] during a visit to Sarajevo. When he heard the news of the assassination, Franz Joseph said that "one has not to defy the Almighty. In this manner a superior power has restored that order which I unfortunately was unable to maintain."[34]
+
+While the emperor was shaken, and interrupted his holiday to return to Vienna, he soon resumed his vacation at his imperial villa at Bad Ischl. Initial decision-making during the "July Crisis" fell to Count Leopold Berchtold, the Austrian foreign minister; Count Franz Conrad von Hötzendorf, the chief of staff for the Austro-Hungarian army and the other ministers.[35] The ultimate resolution of deliberations by the Austrian government during the weeks following the assassination of the Archduke was to give Serbia an ultimatum of itemized demands with which it was virtually certain Serbia would be unable or unwilling to comply, thus serving as a "legal basis for war."
+
+However, the general movement toward war with Serbia was already in motion prior to assassination of the Archduke as evidenced by a 14 June memo of Berchtold recommending the "elimination of Serbia" as a state, which Franz Joseph expressed agreement with in a letter delivered to Kaiser Wilhelm II in Berlin on 5 July. In that letter, Franz Joseph "...explicitly stated that the decision for war against Serbia had been made before the assassination of the Archduke, and that the events of Sarajevo only confirmed the already pre-existing need for a war."
+
+A week after delivery of the Austrian ultimatum to Serbia, on 28 July, Austria-Hungary declared war on Serbia. Within weeks, the Germans, Russians, French and British had all entered the fray which eventually became known as World War I. On 6 August, Franz Joseph signed the declaration of war against Russia.
+
+Franz Joseph died in the Schönbrunn Palace on the evening of 21 November 1916, at the age of 86. His death was a result of developing pneumonia of the right lung several days after catching a cold while walking in Schönbrunn Park with the King of Bavaria.[36] He was succeeded by his grandnephew Charles I, who reigned until the collapse of the Empire following its defeat in 1918.[37]
+
+He is buried in the Imperial Crypt in Vienna, where flowers are still left by monarchists.[citation needed]
+
+It was generally felt in the court that the Emperor should marry and produce heirs as soon as possible. Various potential brides were considered, including Princess Elisabeth of Modena, Princess Anna of Prussia and Princess Sidonia of Saxony.[38] Although in public life Franz Joseph was the unquestioned director of affairs, in his private life his mother still wielded crucial influence. Sophie wanted to strengthen the relationship between the Houses of Habsburg and Wittelsbach—descending from the latter house herself—and hoped to match Franz Joseph with her sister Ludovika's eldest daughter, Helene ("Néné"), who was four years the Emperor's junior.
+
+However, Franz Joseph fell deeply in love with Néné's younger sister Elisabeth ("Sisi"), a beautiful girl of fifteen, and insisted on marrying her instead. Sophie acquiesced, despite her misgivings about Sisi's appropriateness as an imperial consort, and the young couple were married on 24 April 1854 in St. Augustine's Church, Vienna.[39]
+
+Their marriage would eventually prove to be an unhappy one; though Franz Joseph was passionately in love with his wife, the feeling was not mutual. Elisabeth never truly acclimatized to life at court, and was frequently in conflict with the imperial family. Their first daughter Sophie died as an infant, and their only son Rudolf died by suicide in 1889 in the infamous Mayerling Incident.[28]
+
+In 1885 Franz Joseph met Katharina Schratt, a leading actress of the Vienna stage, and she became his friend and confidante. This relationship lasted the rest of his life, and was—to a certain degree—tolerated by Elisabeth. Franz Joseph built Villa Schratt in Bad Ischl for her, and also provided her with a small palace in Vienna.[40] Though their relationship lasted for thirty-four years, it remained platonic.[41]
+
+The Empress was an inveterate traveller, horsewoman, and fashion maven who was rarely seen in Vienna. Sisi was obsessed about preserving her beauty, carrying out many bizarre routines and strenuous exercise, and as a result suffered from ill health. She was stabbed to death by an Italian anarchist in 1898 while on a visit to Geneva. A few days after the funeral, Robert of Parma wrote in a letter to his friend Tirso de Olazábal that "It was pitiful to look at the Emperor, he showed a great deal of energy in his immense pain, but at times one could see all the immensity of his grief."[42] Franz Joseph never fully recovered from the loss. According to the future empress Zita of Bourbon-Parma he told his relatives: "You'll never know how important she was to me" or, according to some sources, "You will never know how much I loved this woman."[43]
+
+Archduke Franz Ferdinand became heir presumptive (Thronfolger) to the throne of Austria-Hungary in 1896, after the deaths of his cousin Rudolf (in 1889) and his father Karl Ludwig (in 1896). The relationship between him and Franz Joseph had always been a fairly contentious one, which was further exacerbated when Franz Ferdinand announced his desire to marry Countess Sophie Chotek, a match that was out of the question in the mind of the emperor, as Sophie was merely of nobility as opposed to being of dynastic rank.
+
+Although the emperor received letters from members of the imperial family throughout the fall and winter of 1899 importuning him to relent, Franz Joseph stood his ground.[44] He finally gave his consent in 1900; however, the marriage was to be morganatic, and any children of the marriage would be ineligible to succeed to the throne.[45] The couple were married on 1 July 1900 at Reichstadt. The emperor did not attend the wedding, nor did any of the archdukes. After that, the two men disliked and distrusted each other.[40]
+
+Following the assassination of Franz Ferdinand and Sophie in 1914, Franz Joseph's daughter, Marie Valerie, noted that her father expressed his greater confidence in the new heir presumptive: his grandnephew Archduke Charles. The emperor admitted to his daughter, regarding the assassination: "For me, it is a relief from a great worry."[46]
+
+Franz Joseph's names in the languages of his empire were:
+
+His official grand title after the Ausgleich of 1867 was: "Francis Joseph the First, by the Grace of God Emperor of Austria, Apostolic King of Hungary, King of Bohemia, King of Dalmatia, Croatia, Slavonia, Galicia and Lodomeria and Illyria; King of Jerusalem etc., Archduke of Austria; Grand Duke of Tuscany and Cracow, Duke of Lorraine, of Salzburg, Styria, Carinthia, Carniola and of Bukovina; Grand Prince of Transylvania; Margrave of Moravia; Duke of Upper and Lower Silesia, of Modena, Parma, Piacenza and Guastalla, of Oświęcim, Zator and Ćeszyn, Friuli, Ragusa (Dubrovnik) and Zara (Zadar); Princely Count of Habsburg and Tyrol, of Kyburg, Gorizia and Gradisca; Prince of Trent (Trento) and Brixen; Margrave of Upper and Lower Lusatia and in Istria; Count of Hohenems, Feldkirch, Bregenz, Sonnenberg, etc.; Lord of Trieste, of Cattaro (Kotor), and over the Windic march; Grand Voivode of the Voivodship of Serbia."[48]
+
+In addition, he founded the Order of Franz Joseph (Franz Joseph-Orden) on 2 December 1849,[55] and the Order of Elizabeth (Elizabeth-Orden) in 1898.[56]
+
+Franz Joseph Land in the Russian Arctic was named in his honour in 1873 by the Austro-Hungarian North Pole expedition which first reported finding it. The Franz Joseph Glacier in New Zealand's South Island also bears his name.
+
+Franz Joseph founded in 1872 the Franz Joseph University (Hungarian: Ferenc József Tudományegyetem, Romanian: Universitatea Francisc Iosif) in the city of Cluj-Napoca (at that time a part of Austria-Hungary under the name of Kolozsvár). The university was moved to Szeged after Cluj became a part of Romania, becoming the University of Szeged.
+
+In certain areas, celebrations are still being held in remembrance of Franz Joseph's birthday. The Mitteleuropean People's Festival takes place every year around 18 August, and is a "spontaneous, traditional and brotherly meeting among peoples of the Central-European Countries".[97] The event includes ceremonies, meetings, music, songs, dances, wine and food tasting, and traditional costumes and folklore from Mitteleuropa.