title: Île de la Cité

text: Henry IV began the practice of selling lots on the island for private townhouses, particularly the development of the Place Dauphine at the east end of the island. In the same century, Louis XIII made a major improvement to the island by building stone river banks to contain the river. This did not prevent a major flood of the Seine in 1689–90, which ruined the lower stained glass windows of the Sainte-Chapelle.


title: Île de la Cité

text: In the 18th century, the Conciergerie on the island became the scene of some of the most dramatic events of the French Revolution. In 1788, the Constituent Assembly, meeting in the former royal palace, refused the demands of Louis XVI to turn over some of its members. In 1790, Jean Sylvain Baily, the mayor of Paris, sealed the doors of the royal palace. In August 1793, Queen Marie-Antoinette was taken to the Conciergerie, where she was imprisoned. After two and a half months she was tried, convicted, and sentenced to the guillotine. In September 1793, the radical Sans-Culottes stormed the Conciergerie and massacred the remaining royalist prisoners. On 27 July 1795, it was the turn of the revolutionary leader Robespierre to be arrested, brought to the Conciergerie, tried, and sent to the guillotine.


title: Île de la Cité

text: Notre Dame de Paris also suffered during the French Revolution; it was closed and then turned into a Temple of Reason; much of the sculpture - particularly in the portals on the west front - was defaced or destroyed. The neighbouring Hotel Dieu hospital sounded too religious for the secular revolutionaries, so its name was changed to the "House of Humanity". Restoration of the revolutionary damage did not begin until the 1830s, particularly following the success of Victor Hugo's 1831 novel "The Hunchback of Notre Dame".


title: Île de la Cité

text: In the early 19th century, with the restoration of the monarchy, the old palace was substantially rebuilt for its function as the center of the judicial system. An expiatory chapel was built where the cell of Marie-Antoinette had been. Between 1820 and 1828, the façade between the Tower of the Horloge and the Tower of Bonbec was rebuilt. It remained a prison; the future Napoleon III was imprisoned there for a time following a failed attempt to overthrow the government.


title: Île de la Cité

text: In the mid-19th century, the island was overcrowded, with narrow streets and poor sanitation. It was hard hit by major cholera epidemics in 1832 and 1849, which killed thousands of Parisians. The new President, and then Emperor, Napoleon III, ordered the demolition of the old streets and buildings and the opening of wide avenues and squares. The Parvis in front of the cathedral was greatly increased in size. In 1867, Napoleon III also demolished the overcrowded medieval hospital, the Hotel Dieu, and replaced it with the present building.


title: Île de la Cité

text: The mid-19th century brought a new campaign of rebuilding and restoration. Between 1837 and 1863, the Saint Chapelle - which had been turned into a storehouse for legal documents - was restored to its medieval splendor. The façade of the Palace of Justice was entirely rebuilt between 1847 and 1871. The medieval hall and the Bonbec Tower were restored to their original appearance.


title: Île de la Cité

text: The Paris Commune of 1871 brought a brief wave of destruction. In the final days of the Commune, the Communards set fire to the Palace of Justice, and attempted to burn down Notre-Dame de Paris. A large part of the Palace of Justice was destroyed, but Notre-Dame was saved by the cathedral staff, suffering only minimal damage. Between 1904 and 1914, the Palace of Justice was finally completed. The Conciergerie had been declared an historic monument in 1862. It was opened to the public in 1914, and the remaining prison sections were closed in 1934.


title: Île de la Cité

text: The Place de l'Île de la Cité is a small park located at the extreme eastern tip of the island, behind the cathedral. It originally was a separate island, called La Motte-aux-Papelards, made up in part of debris from the construction of the cathedral. In 1864, Baron Haussmann chose it as the new site for the Paris morgue, which remained there for fifty years.


title: Île de la Cité

text: Next to the square is the Memorial to the Martyrs of the Deportation, a memorial to the two hundred thousand people who were sent to Nazi concentration camps during World War II. It was dedicated in 1962 by then-President Charles de Gaulle. The monument is at a lower level than the park, reached by a narrow stairway. It is extremely stark and simple, composed of a triangular courtyard giving access to a crypt and corridor. The walls of the crypt are inscribed with the names of concentration camps and with quotations by writers; the corridor is lined with two hundred thousand small glass crystals, each representing a victim of the deportations.


title: Île de la Cité

text: The Cathedral of Notre Dame de Paris is among the most visible and celebrated landmarks of Paris. Construction began in 1163, next to the older Romanesque Cathedral of Saint Etienne, Paris, and was largely completed by 1345. It is among the largest Gothic cathedrals in Europe, with a seating capacity of six-and-a-half thousand. The flèche, or Spire of Notre-Dame de Paris, originally built in 1220–1230, was removed in the 17th century, then rebuilt by Eugene Viollet-Le-Duc in the mid-19th century. At high, it was the tallest structure in Paris until the construction of the Eiffel Tower. The spire and much of the roof were destroyed by the Notre-Dame de Paris fire on 15 April 2019 and the cathedral has been closed for restoration ever since. It is expected to re-open in April 2024.


title: Île de la Cité

text: The parvis or square in front of the cathedral - now officially known as Place Jean-Paul-II - is long and wide, six times larger than the original medieval square. The area in front of the church was packed with narrow houses and streets until Paris was rebuilt in a more expansive style by Napoleon III and Baron Haussmann in the mid-19th century.


title: Île de la Cité

text: Excavations for a car park under the square in 1965 uncovered vestiges of the original Gallo-Roman walls of the city and the Roman baths, dating to the 4th century. They are now open to the public.


title: Île de la Cité

text: A plaque on the parvis thirty meters in front of the central portal marks the point from which distances by road to other cities in France are measured. This same area, in medieval times, was the location of the stocks, where notorious prisoners were displayed in chains.


title: Île de la Cité

text: The statue of Emperor Charlemagne on horseback, by the river in front of the cathedral, is the largest monument on the Parvis. The bronze sculpture was made in 1878 by the brothers Louis and Charles Rochet in the romantic style. The legendary knights Roland and Olivier are portrayed walking alongside the emperor.


title: Île de la Cité

text: A large square – Place Louis-Lepine – is located in the center of the island, in front of the Prefecture of Police. It hosts a famous flower market, which was created by an ordinance of Napoleon in January 1808. It occupies the space between Place-Louis Lepine and the Seine. In 2016 the market was renamed the Marché aux fleurs Reine-Elizabeth-II, during the visit of Queen Elizabeth II to Paris. On Sundays, it also becomes a large market for live birds and other pets. The square is the location of the only metro station on the island, with an Art Nouveau portal designed by Hector Guimard. The metro station is unusually deep — underground — because the tunnel carrying the trains must pass underneath the River Seine.


title: Île de la Cité

text: The Prefecture of Police was built under Napoleon III as a barracks of the Republican Guard. It was gradually expanded into a police headquarters with authority over the twenty districts of Paris and the departments surrounding Paris. During the liberation of Paris in August 1944, the building was the scene of fierce fighting. When the French police went on strike, the occupying German forces attacked the building with tanks. One hundred and sixty-seven policemen were killed.


title: Île de la Cité

text: Alongside the Quai de la Corse, at the Pont au Change, is the Tribunal de Commerce de Paris, which contains the courts of business and commerce. The judges of this court are not lawyers, but business people elected for 2–4 year terms. The building was constructed between 1860 and 1865 in the extremely ornate Louis XIII style - like the Palais Garnier opera house, built at about the same time. Its dome was inspired by the New Cathedral, Brescia in Italy, begun in 1604 but not finished until 1825. Napoleon III had admired it in 1859 during his military campaign which liberated Italy from Austrian rule.


title: Île de la Cité

text: The Hôtel-Dieu, located between the Parvis of Notre-Dame on the south and the Quai de la Corse on the north, is the oldest hospital in Paris. It is reputed to be the oldest still-functioning hospital in the world. Tradition says it was founded in 651 by Saint Landry, Bishop of Paris. It was originally located on the other side of the Parvis, along the river, with a second building on the left Bank of the Seine. The old hospital was famous for its overcrowding, with several patients in each bed. It was rebuilt several times. During the French Revolution it was re-named the "House of Humanity", in keeping with the secular principles of the revolution. The present hospital was begun by Napoleon III in 1863 and completed in 1877. The design, in an Italian Renaissance style, was by the architect Arthur-Stanislas Diet. It has several buildings, connected by porticos. Until 1908, care in the hospital was provided by nuns; now it is part of the network of Paris public hospitals.


title: Île de la Cité

text: Historical buildings close to the same site included the Hospice of Found Children, built in 1670, where new-born babies could be abandoned without explanation at any hour of the day or night. It received up to eight thousand children a year before the French Revolution.


title: Île de la Cité

text: Most of the very old residential quarters on the island were destroyed by Napoleon III and Baron Haussmann in the 19th century. Only one small area remains: the Canons' Quarter (Quartier des Chainoines), located between the Quai aux Fleurs, the rue d'Arcole and the rue du Cloitre-Notre Dame. In the 16th century it was the residence of many of the canons of the cathedral. It was closed to the outside world by gates, no commerce was permitted, and no women were allowed except those of "respectable age." Several residences remain from this period; the house at 24 rue Chanoinesse, from about 1512, has large doors leading to an interior courtyard and dormer windows jutting up from the roof. It is now covered with wisteria. Another good example is found at 12 Rue Chanoinesse.


title: Île de la Cité

text: One celebrated inhabitant of the neighborhood was the playwright Jean Racine, who lived on the second floor in the courtyard of the house at 7 rue des Ursines between 1672 and 1677. Another famous resident was Héloïse, the daughter of a canon named Fulbert, who lived at 9 Quai aux Fleurs. She was seduced by her philosophy teacher, Peter Abelard, in 1418. In what became one of the most celebrated romantic tragedies in French history, she secretly married Abelard; her furious father had him arrested and castrated. Both Abelard and Heloise finished their lives living in monasteries. The original house of Héloïse was demolished in 1849, but the present house has a plaque commemorating its role in the tragic story.


title: Île de la Cité

text: The old royal palace lay along the Quai de l'Horloge, on the northeast side of the island. With the departure of the kings of France to the Louvre and then to Versailles, the palace gradually was transformed into the judicial center of the Kingdom, containing the courts, administrative offices and a prison.


title: Île de la Cité

text: The Quai de l'Horloge takes its name from the clock in the tower on the northeastern corner of the palace. The tower was built between 1350 and 1353 as a watchtower. When it was constructed, it was directly on the Seine. The stone walls of the Quai de l'Horloge, built beginning in 1611, created space for a road. The first clock was ordered by Charles V, and faced the interior of the palace. In 1418 it was given an outside face, toward the city, and became the first municipal clock of Paris. In the 16th century, Henry III had the clock redecorated with sculpture by the French Renaissance sculptor Germain Pilon. The tower was originally topped by a silver bell, rung only to announce he death of the king or the birth of his heir. It was also rung on 24 August, 1572, at the beginning of the St. Bartholomew's Day Massacre, to signal the beginning of the attack on the Protestants of Paris. The original bell was melted down during the French Revolution, but was replaced in 1848. The gilding of the clock was restored in 2012.


title: Île de la Cité

text: During the French Revolution, the attic on the top floor between the Silver Tower and Bonbec Tower was the home of Antoine Quentin Fouquier-Tinville, the chief prosecutor of the Revolutionary Tribunal. He lived there with his wife and twins while conducting the trials in the lower courtroom which sent more than two thousand prisoners to the guillotine.


title: Île de la Cité

text: Most of the facade along the Seine on the Quai de l'Horloge was rebuilt in the Neo-Gothic style in the 19th century. The exceptions are the three towers that follow the tower of the Horloge, which date to about 1300, in the reign of Philip IV. The Tower of Caesar and the Silver Tower flank the gateway. The Tower of Caesar was built on a Gallo-Roman foundation, while the Silver Tower served as the royal treasury. The third and oldest tower - the only one with tooth-like crenellations around the top - is the Tower Bonbec. It was built by Louis IX, at the same time as the Sainte-Chapelle. Beginning in the 15th century it contained the torture chamber of the palace. For this reason its name was reputed to come from the expression "Bon Bec", or "To quickly untie the tongue."


title: Île de la Cité

text: The parts of the palace further west were constructed under Napoleon III in the neo-classical style, with Corinthian pillars. The buildings were gradually taken over entirely by the judicial function. They now house the highest court in France: the Court of Appeals, created in 1790. The various buildings of the Palais de Justice cover about a third of the island, and at their peak employed about four thousand employees. They are still occupied largely by the courts and offices of the justice system, though some functions have moved to a new building on the outskirts of Paris.


title: Île de la Cité

text: The main entrance is located on the Boulevard du Palais, behind a very elaborate wrought-iron gate. The main entrance dates to 1783–87, and features a grand staircase and classical peristyle. Until the 1840s, the entry courtyard was also occupied by the stalls of merchants, making it extremely lively.


title: Île de la Cité

text: The older portion of the building, the Conciergerie, was turned into a state prison from about 1370, as the Kings moved out to live elsewhere. The original entrance to the building was on what is now the first floor, since the street level was gradually raised. Within the entrance is a very large Gothic hall, with four naves divided by rows massive pillars, which was originally known as the Hall of the Men-at-Arms. It was used primarily as a dining hall for the two thousand employees in the King's service. Four stairways originally reached upward to the grand ceremonial hall on the first floor, where the Parliament met and court festivities were held. Most of this floor was destroyed by fire in 1618, but some vestiges remain, including pieces of the enormous black marble table that was a centrepiece of the hall. They now hang on the south wall of the lower chamber.


title: Île de la Cité

text: The residence of the king originally adjoined this part of the Palace, but its last remains were destroyed in the fires set by the Paris Commune in 1871. All that remains of his residence is the Guards' Hall: originally, an antechamber to the residence. From the west side of the back wall runs a passage known as the "Rue de Paris"; it was used by the royal executioner, nicknamed "Monsieur de Paris".


title: Île de la Cité

text: A few portions of the old prison, which was in use from 1370 to 1914, still exist. The Revolutionary Tribunal was established on the first floor of the Palace of Justice from September 1793 until the fall of Robespierre in 1794. The prisoners were crowded into common cells, and were not told of the specific charge against them until the day before the trial. The public prosecutor, Fouquier-Tinville, prepared execution sentences in advance with the names left blank - to speed the court procedure. After very rapid trials with little opportunity for defence, the tribune sent thousands of prisoners to the guillotine. Convicted prisoners were usually executed the day after their trial. They had their necks shaved and their collars widened, and were taken in cartloads of ten or twelve prisoners to the Place de la Revolution (today's Place de la Concorde) for execution. In all, two thousand, seven hundred and eighty people were convicted and executed in this manner. Reconstructions of some of the cells can be seen today.


title: Île de la Cité

text: The best-known victim of this process was Queen Marie-Antoinette, who was held at the Conciergerie for seventy-six days: from 2 August until 16 October 1793. She was confined to a small cell where she was watched day and night by two guards until her trial. The following day, she was taken on a cart to her execution, along a street lined with thirty thousand soldiers and crowds of jeering Parisians. After the Restoration of the monarchy, in 1816, her original cell was transformed into a chapel. Another cell nearby, very similar to her original cell, gives visitors an idea of her final days.


title: Île de la Cité

text: The Sainte-Chapelle was the royal chapel, located in the courtyard of the palace. It was created by Louis IX (later Saint Louis) to display sacred relics of the Crucifixion; particularly the Crown of Thorns that he purchased in 1239 from the Emperor of Constantinople. He later added what was believed to be a fragment of the true cross. Work was already underway by 1241, and it was consecrated in 1248.


title: Île de la Cité

text: The Sainte-Chapelle measured high – not counting the spire – which ranked it with the major cathedrals of the time. By comparison, the nave of Notre Dame de Paris is high. The current spire is high, but it is not original. In fact, it is the fifth spire to adorn the Sainte-Chapelle. It was made in 1852–53, following the model of the 15th century spire. The 19th-century sculpture, inspired by medieval models, was cast in lead by Geoffrey-Dechaume.


title: Île de la Cité

text: The great treasure of The Sainte-Chapelle is the 13th century stained glass windows; the glass was thicker than later windows, and consequently the colors were deeper and richer, with reds and blues predominant. There are more than thirteen hundred small panels of stained glass, each containing a biblical scene. More than two-thirds of the original stained glass survived, including fifteen Early Gothic windows from the 13th century and the later Gothic rose window from the 15th century. The upper portion of the chapel, where the relics were displayed, was reserved for the royal family, while the ground floor was used by the courtiers and servants of the court.


title: Île de la Cité

text: The chapel suffered major damage during the French Revolution. Afterwards, it was turned into a storehouse of documents for the neighbouring Ministry of Justice.


title: Île de la Cité

text: The Quai des Orfèvres, "The Quay of the Goldmsiths and Silversmiths", is on the southwestern side of the island, alongside the Palace of Justice and the Place Dauphine. In its earlier days, a poultry market was held here; as a result policemen were referred to by the slang term "poulets" or "chickens". Its current name dates from the 17th and 18th centuries, when many celebrated Paris jewellers had their shops here; including Boehmer and Bassenge - who made a famous necklace for Marie-Antoinette - and Georg Friedrich Strass, who invented both the rhinestone and the synthetic diamond.


title: Île de la Cité

text: The jewellers' shops have since disappeared, but the street is notable for the imposing office building at 36 Quai de Orfèvres. Constructed between 1875 et 1880 by architects Émile Jacques Gilbert and Arthur-Stanislas Diet, it replaced an earlier building of the President of the Court of Appeals of Paris, which was destroyed by the Paris Commune in 1871. As the home of the "Direction régionale de la police judiciaire de la préfecture de police de Paris" (Directorate of the Judicial Police of the Paris Prefecture), its address featured in the titles of several very popular French films and detective novels. The fictional detective Inspector Jules Maigret, created by Georges Simenon, had his office here. The police moved out, to the rue Bastion in the 17th Arrondissement, in 2017.


title: Île de la Cité

text: Rue de Harlay runs across the island on the northwest side, separating the Palais de Justice from the Place Dauphine. It is named for Achille de Harlay, the first president of the Parliament of Paris in the early 17th century; his house stood in that location until it was demolished for the enlargement of the Palace of Justice. The building of the Cour de Cassation, a kind of French Supreme Court, looks over the Place Dauphine. Its highly theatrical facade was designed by Joseph-Louis Duc, whose other famous Paris work is the July Column in the Place de la Bastille. It features marble classical columns, pediments and bas-reliefs; there are sculpted lions on the grand stairways, eagles on the roof and statues of famous jurists in togas along the facade. Like the Paris Opera of the same period, it is in the style of Napoleon III. It was nearly completed in 1871 when Napoleon III was deposed. The Paris Commune set fire to the unfinished palace, partially destroying it; but it was later restored and completed.


title: Île de la Cité

text: One famous feature is the Hall of the "Pas Perdus", or "Last steps", where prisoners would be taken between the courtrooms and the prison.


title: Île de la Cité

text: The triangular Place Dauphine, at the downstream end of the island, was originally the garden of the royal palace. Known as "The King's Orchard", it was filled with vegetable gardens, fruit trees and flower beds. Beginning in 1609 King Henry IV turned it into a residential square, facing the palace, similar to the square he began at the Place des Vosges a few years earlier. It was named for his son, the Dauphin of France (the future Louis XIII). He asked the president of the Parliament, to develop it. Twelve lots were sold, and forty-five irregularly sized houses were constructed behind a standardised façade. The houses were built of brick, with limestone quoins supported on arcaded stone ground floors and capped by steep slate roofs with dormers - similar to the façades of Place des Vosges. Each house had a ground floor of arcades occupied by shops; two floors of living space; and an attic with skylights.


title: Île de la Cité

text: There were originally two entrances to the Place Dauphine. One was at the downstream end, entering through a kind of gateway centred on paired pavilions facing the equestrian statue of Henry IV on the far side of the Pont Neuf. The second was in the center of the eastern row of houses, which were badly damaged during the Paris Commune of 1871. Nearly all the buildings have been raised in height, given new façades, or replaced with modified versions of the originals. Notable residents of the Place included the film stars Yves Montand and Simone Signoret, who occupied 15 Place Dauphin - above a bookstore - from their wedding in 1952 until the death of Signoret in 1985.


title: Île de la Cité

text: The Pont Neuf, completed in 1606, was the first bridge in Paris to cross the entire length of the Seine, and the first that was not lined with houses. It was the project of Henry IV. After the assassination of the king in 1610, it became the site of another innovation: the first equestrian statue in Paris. Commissioned in 1614 by Marie de' Medici - the widow and regent of the king - it was modelled after the equestrian statues of her native Italy. Giambologna completed the commission in 1618. The statue was destroyed in 1792 during the French Revolution, but was replaced in 1817 by the royal sculptor François Lemot, using casts of the original.


title: Île de la Cité

text: At the time that the statue was installed on the bridge, it stood at the very tip of island. In 1884 the end of the island was extended over a sandbar with the construction of new quays, and planted with trees. This became the new Square of Vert-Galant. Its name comes from the king's nickname as an admirer of women. The triangular park has some of the finest views of the buildings along both sides of the Seine.


title: Île de la Cité

text: From early times wooden bridges linked the island to the riverbanks on either side. The Grand Pont (or Pont au Change) spanned the wider reach to the Right Bank, while the Petit Pont crossed the narrower channel to the Left Bank. The first stone bridge was built in 1378 at the site of the present Pont Saint-Michel; but ice floes carried it away, along with all the houses on it, 1408. The Grand Pont or Pont Notre-Dame - also swept away at intervals by floodwaters - and the Petit Pont were rebuilt by Fra Giovanni Giocondo at the beginning of the 16th century.


title: Île de la Cité

text: The six arches of the Pont Notre-Dame supported gabled houses, some of half-timbered construction, until all were demolished in 1786.


title: Île de la Cité

text: The island has one Paris Métro station: Cité. There is also one RER station: Saint-Michel-Notre-Dame, although on the Left Bank, has an exit on the island in front of the cathedral.


title: Turbo: A Power Rangers Movie

text: Turbo: A Power Rangers Movie is a 1997 American superhero film directed by David Winning and Shuki Levy and written by Levy and Shell Danielson. It is the second installment in "Power Rangers" film series after "" and was produced by Saban Entertainment and Toei Company, Ltd., and was distributed by 20th Century Fox. The film stars Johnny Yong Bosch, Nakia Burrise, Steve Cardenas, Jason David Frank, Austin St. John, Catherine Sutherland, Jason Narvy, Paul Schrier, Hilary Shepard Turner, Amy Jo Johnson, and Blake Foster.


title: Turbo: A Power Rangers Movie

text: Taking place after the events of "Power Rangers Zeo", the new cast and characters from the film become cast members of "Zeo"' s successor series, "Power Rangers Turbo", with the film's events leading into the successor series. As with its television season, the film used concepts and costumes from the Japanese Super Sentai series "Gekisou Sentai Carranger". Sets and costumes created for original characters in the film were later used in the television series, with the film's climactic antagonist Maligore being reused for the evil Dark Specter in the subsequent "Power Rangers in Space" season.


title: Turbo: A Power Rangers Movie

text: The film was released on March 28, 1997, to generally unfavorable reviews. It was criticized for its visual effects and campiness, but critics praised the performance of its cast.


title: Turbo: A Power Rangers Movie

text: On the planet Liaria, a wizard named Lerigot is being hunted down by Divatox; an intergalactic space pirate, who is seeking his golden key to traverse an inter-dimensional gateway and enter into matrimony with Maligore, an imprisoned demon who promises her great riches and power. Lerigot escapes Divatox's forces and travels to Earth in search of Zordon and his friend Alpha 5, but arrives in Africa by accident. Weakened by the sun's ultraviolet rays, Lerigot meets a tribe of chimpanzees and wanders off with them. Meanwhile, Divatox heads for Earth in pursuit.


title: Turbo: A Power Rangers Movie

text: In Angel Grove, Rocky DeSantos, Adam Park, and Tommy Oliver are training for a charity fighting competition to save the Youth Shelter, when Rocky accidentally injures his back. Katherine Hillard and Tanya Sloan arrive with Justin Stewart, a kid who admires Rocky and frequents the shelter. As Rocky is rushed to the hospital, Justin follows the group and learns they are Power Rangers. Zordon sends Tommy and Katherine to search for Lerigot. They manage to find him and return to the Power Chamber.


title: Turbo: A Power Rangers Movie

text: Searching for two human sacrifices to revive Maligore, Divatox's nephew Elgar, abducts Farkus "Bulk" Bulkmeier and Eugene "Skull" Skullovitch, but Divatox rejects them for not being pure of heart. Upon finding Kimberly Hart and Jason Lee Scott, who are scuba diving nearby, Divatox captures them. While recovering, Lerigot is contacted by Divatox, who has captured his family and demands he surrender himself. Divatox also uses Kimberly and Jason to pressure the Rangers. At the exchange site, Elgar tricks the Rangers and captures Lerigot.


title: Turbo: A Power Rangers Movie

text: Zordon and Alpha create new powers for the Rangers to defeat Divatox. With these new powers and new vehicular Turbo Zords, the Rangers travel across the desert to a ship called the Ghost Galleon. They are joined by Justin, who has received Rocky's Blue Ranger powers while Rocky is recovering in the hospital. On Divatox's submarine, Jason and Kimberly come up with a plan to escape, but though Bulk, Skull, and Kimberly escape the sub, Jason is trapped and left behind.


title: Turbo: A Power Rangers Movie

text: After Divatox and the Rangers traverse the Nemesis Triangle and reach the island where Maligore is, Divatox torpedoes the Ghost Galleon and the Rangers narrowly escape. Kimberly is recaptured and brought to Divatox by the tribal natives of the island who worship Maligore as their god. At the temple in the volcano, the Rangers fail to free Jason and Kimberly before they are possessed by Maligore and attack the Rangers mercilessly, but the Rangers succeed in freeing Lerigot and his wife Yara, who undo the possession.


title: Turbo: A Power Rangers Movie

text: Angered, Divatox sacrifices her nephew and successfully revives Maligore. The Rangers combined their Turbo Zords and form the Turbo Megazord to fight Maligore. They defeat him as Divatox and Rygog flee, vowing vengeance. The Rangers pick up Jason, Kimberly, Lerigot, Yara, Bulk and Skull and return to Angel Grove. At the competition, Jason takes Rocky's place, and they win the fight, earning the money to save the shelter.


title: Turbo: A Power Rangers Movie

text: Additionally, Gregg Bullock reprises his role as Lt. Jerome Stone from "Power Rangers Zeo". Richard Genelle reprises his role as Ernie, the Angel Grove Gym and Juice Bar's owner; Winston Richard plays Zordon, an inter-dimensional wizard and the Rangers' mentor, with Bob Manahan voicing the character; and Donene Kistler plays Alpha 5, a robot from Edenoi and Zordon's assistant, with Richard Wood voicing Alpha 5. Jon Simanton portrays Lerigot, a wizard who holds a magical key that can open portals to worlds and realms, while Lex Lang provided the voice for the character. Divatox's henchmen includes Lang also voices Rygog, one of Divatox's henchmen. J.B. Levine voice Yara and Bethel, Lerigot's wife and daughter. Danny Wayne Stallcup physically portrays Elgar, Divatox's dimwitted nephew, while David Umansky provides his voice. Mike Deak portrays Maligore, Divatox's fiancé and true antagonist of this movie. Carla Perez reprises her role as Rita Repulsa, a sorceress who has fought the Power Rangers in the past, with Barbara Goodson providing her voice.


title: Turbo: A Power Rangers Movie

text: As opposed to the CGI Megazord used in the first Power Rangers film, this sequel uses a practical costume for the Turbo Megazord. The television series would instead rely on "Carranger" footage.


title: Turbo: A Power Rangers Movie

text: Between production of the film and television series, Hilary Shepard Turner took maternity leave and was initially replaced by Carol Hoyt as Divatox. Shepard resumed the role in the 26th episode, continuing through "Power Rangers in Space".


title: Turbo: A Power Rangers Movie

text: Turbo: A Power Rangers Movie (Original Motion Picture Soundtrack) is the licensed soundtrack to the film. It was released by Hollywood Records on March 18, 1997, on Audio CD and Compact Cassette.


title: Turbo: A Power Rangers Movie

text: The album serves a dual purpose, as it not only used much of the music heard in the movie, but also contained several tracks from "".


title: Turbo: A Power Rangers Movie

text: The film was released on July 8, 1997, on VHS and LaserDisc. The film (as well as 1995's "") was then released on a two-sided DVD disc on March 13, 2001, and then re-released on a single-sided disc in 2003. This film was re-released with different packaging in 2011. The film was then re-released in March 2017 in a bundled set with "Mighty Morphin Power Rangers: The Movie" to coincide with the release of the 2017 film "Power Rangers".


title: Turbo: A Power Rangers Movie

text: In 2019, it was announced that Shout! Factory had acquired the rights to re-release the movie and confirmed that "Turbo: A Power Rangers Movie" would be released for the first time on Blu-ray. It was released on July 30, 2019.


title: Turbo: A Power Rangers Movie

text: "Turbo: A Power Rangers Movie" opened theatrically on March 28, 1997, in 2,113 venues. It earned $3.3 million in its opening weekend, ranking number seven in the domestic box office. At the end of its run, the film had grossed $8.4 million in North America and $1.3 million overseas for a worldwide total of $9.6 million.


title: Turbo: A Power Rangers Movie

text: On Rotten Tomatoes the film has an approval rating of based on reviews, with an average rating of . " On Metacritic, it has received a weighted average score of 35 out of 100, based on 9 reviews, indicating "generally unfavorable reviews". Audiences surveyed by CinemaScore gave the film a grade B on scale of A to F.


title: Turbo: A Power Rangers Movie

text: Joe Leydon of "Variety" criticized the "high-camp cheesiness" and praised the acting of both Hilary Shepard Turner and Amy Jo Johnson. Lawrence Van Gelder of "The New York Times" has mixed feelings on the film, criticizing the storyline and dialogue and praising the visual effects and production values. Rita Kempley of "The Washington Post" called it "A purgatory of low-budget interplanetary adventure."


title: Turbo: A Power Rangers Movie

text: Kevin Thomas of the "Los Angeles Times" gave a positive review, saying the filmmakers have brought "much panache and sophistication to the making of this fantasy adventure extolling the good old-fashioned virtues of spirit and courage embodied by the Power Rangers" and that ""Turbo" is a solid follow-up." He also praised Turner's acting and the visual effects.


title: Turbo: A Power Rangers Movie

text: Blake Foster was nominated for Best Performance in a Feature Film - Leading Young Actor at the 1998 Young Artist Awards.


title: The Shadowhunter Chronicles

text: The Shadowhunter Chronicles is a media franchise based on the writings of American young adult fiction writer Cassandra Clare, which currently encompasses six series of novels, three short-story collections, five graphic novels, one film, a television series, and other media.


title: The Shadowhunter Chronicles

text: These works are set in a universe where fairy tales and mythologies, both pagan and Judeo-Christian, exist with its figures existing alongside the mundanes (normal humans). A race of humans who possess angel blood, the Nephilim or Shadowhunters, is organized to patrol the Shadow World and prevent demons as well as Downworlders, including warlocks, faeries, werewolves, and vampires, from attacking the mundanes. There is an uneasy peace, a treaty known as The Accords, between the governing body of the Nephilim, known as the Clave, and the Downworlders, not all of whom want peace or respect the Clave's authority.


title: The Shadowhunter Chronicles

text: "The Infernal Devices" is the second set of books published. Set in 1878 in Victorian era London, it revolves around Tessa Gray, a teenager who comes to London following her brother's invitation but ends up thrust into the Shadow World upon learning she is not a mundane but, rather, a warlock variant, warlocks being half-human and half-demon. Tessa is unique even among warlocks, as she is the only known case of having Nephilim heritage. The Nephilim, here textually often referred to as Shadowhunters, are blessed with the blood of the angel, thus making Tessa a fourth seraphic.


title: The Shadowhunter Chronicles

text: "The Last Hours" is the fifth set of books to all be published. The sequel to "The Infernal Devices" series, it is set in 1903 London and Paris and revolves around Tessa's children, James and Lucie, as well as their family friend, Cordelia Carstairs, as they navigate through the politics of the London Enclave.


title: The Shadowhunter Chronicles

text: "The Mortal Instruments" is the first set of books published. The series is mainly set in the year 2007 and revolves around the Shadowhunter Clary Fairchild. She and her friends are confronted with two wars: the first against Valentine Morgenstern, and the second against his son Jonathan Morgenstern.


title: The Shadowhunter Chronicles

text: "The Eldest Curses" is the fourth set of books all to be published. The trilogy tells the story of Magnus Bane and Alec Lightwood's adventures together and explore their relationship. Each book is set at different points in the franchise's timeline: the first is set during the events of "The Mortal Instruments"; the second is set between the events of "The Mortal Instruments" and "The Dark Artifices"; and the last will be set after "The Dark Artifices". The books were jointly written by Cassandra Clare and Wesley Chu.


title: The Shadowhunter Chronicles

text: "The Dark Artifices" is the third set of books published. The sequel to "The Mortal Instruments" series, it takes place in 2012, five years after the events of that series's final book, "City of Heavenly Fire". It revolves around the Shadowhunter Emma Carstairs, first introduced in "City of Heavenly Fire", as she seeks the answer for her parents' mysterious deaths.


title: The Shadowhunter Chronicles

text: "The Wicked Powers" will be the sixth and final set of books to be published and serve as the conclusion of "The Shadowhunter Chronicles". It will be based in 2015, three years after the events of the final book of "The Dark Artifices" - "Queen of Air and Darkness" - and will centre around the characters of Kit Herondale, Ty Blackthorn and Dru Blackthorn.


title: The Shadowhunter Chronicles

text: In 2010, Screen Gems announced that they were going into production on the of "City of Bones", the first book in "The Mortal Instruments" series, with hopes of starting a successful film franchise. The film was originally due for release on August 23, 2013, but was pushed back two days earlier, on August 21, 2013. The film premiered on August 12, 2013, at the Cinerama Dome in Hollywood. Production on a film adaptation of the second book, "City of Ashes", was due to start in September 2013, but was delayed to 2014, and eventually cancelled, after the first film failed to recoup its budget.


title: The Shadowhunter Chronicles

text: On October 12, 2014, at Mipcom, Constantin confirmed that "The Mortal Instruments" will return as a television series with Ed Decter as showrunner. Constantin Film and TV head Martin Moszkowicz told "The Hollywood Reporter" that, "It actually makes sense to do [the novels] as a TV series. There was so much from the book that we had to leave out of the "Mortal Instruments" film. In the series we'll be able to go deeper and explore this world in greater detail and depth." The producers hope to adapt the entire book series if the TV adaptation proves successful. In February 2015, book series author Cassandra Clare announced via Twitter that the television series would be called "Shadowhunters" rather than "The Mortal Instruments".


title: The Shadowhunter Chronicles

text: In March 2015, ABC Family picked up Shadowhunters straight-to-series, and premiered on January 12, 2016. The series was renewed for a second season in March 2016, comprising 20 episodes, which premiered on January 2, 2017. In April 2017, it was announced that the series was renewed for a third season of 20 episodes. The first half of ten episodes premiered on March 20, 2018. On June 4, 2018, Freeform canceled the series after three seasons, but ordered two extra episodes to properly conclude the series' story; the second half of the third season premiered on February 25, 2019.


title: Martin Crowe

text: Martin David Crowe (22 September 1962 – 3 March 2016) was a New Zealand cricketer, Test and ODI captain as well as a commentator. He played for the New Zealand national cricket team between 1982 and 1995, and is regarded as one of the country's greatest batsmen.


title: Martin Crowe

text: Crowe made his first-class debut for Auckland at the age of 17, and his Test debut for New Zealand at the age of 19. He was named a Wisden Cricketer of the Year in 1985, and was credited as one of the "best young batsmen in the world". Crowe was appointed New Zealand's captain in 1990, and led the team until 1993. In a Test against Sri Lanka in 1991, he scored 299 runs, breaking the record for the highest score by a New Zealander. In the same match, he also set a new record for the highest partnership in Test cricket, putting on 467 runs with Andrew Jones. At the 1992 World Cup, which New Zealand co-hosted with Australia, Crowe was named the player of the tournament, and led his team to a semi-final. By the time he finished his international career in 1995, he held the records for the most Test and One Day International (ODI) runs scored for New Zealand.


title: Martin Crowe

text: After retiring from playing, Crowe remained involved in cricket as a writer and commentator. He was diagnosed with lymphoma in 2012, but was declared cancer-free the following year. However, the disease returned in 2014, and eventually led to his death in 2016. He was also one of the main brains of initiating the ICC World Test Championship concept which was initially proposed in 2009 but did not materialise until 2019.


title: Martin Crowe

text: Crowe was born in Henderson, a suburb of Auckland, to a family of cricketers. His father, Dave Crowe, played first-class cricket for Canterbury and Wellington and his older brother, Jeff Crowe, played Test cricket. One of the brothers' first cousins is actor Russell Crowe. In 1968, Martin Crowe joined his father and brother at the Cornwall Cricket Club, with which he maintained a lifelong connection. At Auckland Grammar School, which he attended from 1976 to 1980, he was deputy head boy in his final year. He captained the school's cricket team, and also played rugby union, as a wing. He was also the great grandson of All Black Francis Jervis (his mother's maternal grandfather).


title: Martin Crowe

text: Crowe made his first-class debut in January 1980, playing for Auckland against Canterbury. Aged 17 at the time, he scored 51 runs in his first innings, which was his team's highest score. In 1981, having been named New Zealand's Young Cricketer of the Year, Crowe was given the opportunity to spend six months on the ground staff of Lord's, simultaneously playing for the Marylebone Cricket Club. Returning to New Zealand for the 1981–82 domestic season, he scored a maiden first-class century, making 150 runs against Canterbury. Crowe switched to Central Districts after the 1982–83 season. His career for Central Districts was limited by his international duties, but in 32 first-class appearances (from 1983 to 1990), he averaged 68.72, with 13 centuries. Crowe's highest score for the team (and in all New Zealand domestic cricket) was 242, made against Otago in January 1990. That season was his last for Central Districts, as he transferred to Wellington prior to the 1990–91 season. In five seasons for Wellington, Crowe made only nine first-class appearances, the last of which came during the 1994–95 season.


title: Martin Crowe

text: In 1984, Crowe signed to play English county cricket with Somerset. He had great success in his first County Championship season, finishing second behind Vic Marks in Somerset's averages and placing sixth for overall runs scored. However, Crowe did not return to the county until the 1987 season. In that year's County Championship, he placed third in the overall averages (behind teammate Steve Waugh and Northamptonshire's Roger Harper), and also placed third for overall runs scored (behind Graeme Hick and Graeme Fowler). Against Hampshire in the 1987 Benson & Hedges Cup (a limited-overs competition), he scored 155 not out from 119 balls, which was the highest one-day score of his career. Crowe returned for a final season at Somerset in 1988, but was able to play only a handful of matches. From 48 matches for Somerset, he finished with a first-class batting average of 59.46.


title: Martin Crowe

text: Crowe made his international debut for New Zealand in February 1982, in a One Day International (ODI) game against Australia played at Auckland's Eden Park. He made his Test debut at the end of the month, playing against the same team at Wellington's Basin Reserve. At the time, only six New Zealanders had made their Test debuts at a younger age. At the 1983 World Cup in England, Crowe played in all six of his team's matches, with only Geoff Howarth scoring more runs. His highest score was 97, made in the opening game against England. In January 1984, when England toured, Crowe scored his first Test century – 100 runs exactly.


title: Martin Crowe

text: In 1985, Crowe made two scores of 188. The first came on a mid-year tour of the West Indies, with Crowe at the crease for 462 balls and over nine hours. The second came in an end-of-year tour of Australia, in a match that was better known for Richard Hadlee's 15-wicket haul. In a Test against the West Indies in February 1987, Crowe and John Wright put on 241 runs for the third wicket, setting a new third-wicket record for New Zealand. Later in the year, Crowe played in the 1987 World Cup in India. He finished as New Zealand's leading run-scorer, making three half-centuries from six matches, although his team struggled (winning only against Zimbabwe).


title: Martin Crowe

text: Crowe was first appointed captain of New Zealand for a tour of Pakistan in October and November 1990. Before that point, he had been regarded as "captain designate" to John Wright, who was nearing the end of his international career. Crowe's second series as captain came in early 1991, when Sri Lanka toured. In the first Test of the series, played in Wellington, Crowe scored 299 runs in his team's second innings, setting a new record for the highest score by a New Zealander. He was at the crease for 523 balls and over ten hours, and scored 29 fours and three sixes. Crowe and Andrew Jones (who scored 186) put on 467 runs for the third wicket, setting a new record for the highest partnership in Test cricket. The pair helped New Zealand, behind by 323 runs on the first innings, to score 671/4 at the end of the final day's play, which at the time was the highest score in the third innings of a Test.


title: Martin Crowe

text: At the 1992 World Cup, which New Zealand co-hosted with Australia, Crowe finished as the tournament's leading run-scorer with 456 runs, and was named player of the tournament. One of his highlights was an innings of 100 not out in the opening match against Australia, which New Zealand won by 37 runs. In the tournament's group stages, New Zealand lost only a single game, against Pakistan. They topped the table, qualifying for a home semi-final against the same team (their first finals appearance since the 1979 tournament). Crowe chose to bat first, and scored 91 runs from 83 balls to help his team to a total of 262/7. However, when Pakistan batted, he chose to stay off the field and rest an injured hamstring, with John Wright taking over on the field. Pakistan won the match by four wickets. Crowe largely blamed himself for his team's loss, and in a 2014 article said that his decision not to take the field was "a curse that had tormented me for over two decades".


title: Martin Crowe

text: Crowe's last series as captain of New Zealand came when Australia toured in February and March 1993. He had struggled with injuries for several years, and was replaced by Ken Rutherford to allow him to concentrate on his form. However, he returned as captain for one final match in November 1993, the first game of a series against Australia. In total, Crowe captained New Zealand in sixteen Tests, winning only two. He had a much better record in ODIs, with the team winning 21 out of 44 matches under his captaincy. Crowe was described by broadcaster Bryan Waddle as a "proactive rather than reactive" leader, who was "always prepared to be innovative". He had a troubled relationship with the media throughout his captaincy, in one case using a press conference to confront a journalist who had published an article implying he had AIDS.


title: Martin Crowe

text: In his first series after giving up the captaincy, a 1994 tour of England, Crowe scored consecutive centuries, making 142 at Lord's and 115 at Old Trafford. His series tally of 380 runs was the second-highest of his career. Crowe continued playing for several more seasons, eventually retiring after a tour of India in October and November 1995. He scored his final international hundred in the first ODI of the tour, aged 33. Crowe finished with 5,444 Test runs and 4,704 ODI runs, both New Zealand records at the time. At the time of his retirement, only Sir Richard Hadlee had played more Tests for New Zealand. Crowe held the record for the most Test centuries by a New Zealander at the time, finishing with seventeen (including one against every Test-playing team but South Africa).


title: Martin Crowe

text: In the 1992 New Year Honours, Crowe was appointed a Member of the Order of the British Empire, for services to cricket. On 28 February 2015, Crowe was inducted into the ICC Cricket Hall of Fame. He was inducted in a ceremony during the lunch break of New Zealand's win against Australia during the 2015 World Cup.


title: Martin Crowe

text: Crowe made 21 centuries in international cricket, 17 in Tests and 4 in One Day Internationals. He scored his first Test century against England, also at the Basin Reserve on 20 January 1984, scoring 100. He scored his final Test century, also against England at Old Trafford, Manchester on 30 June 1994, scoring 115. He played his final Test match against India at the Barabati Stadium, Cuttack on 8 November 1995, having played 77 matches. His highest score in Tests is 299, scored against Sri Lanka at the Basin Reserve on 31 January 1991.


title: Martin Crowe

text: He scored his first ODI century against England, also at Eden Park, scoring 105 not out. He scored his final ODI century against India at the Keenan Stadium, Jamshedpur on 15 November 1995, scoring 107 not out, his highest score in ODIs. He played his final ODI in the final game of the same series against India at the Vidarbha Cricket Association Ground, Nagpur on 26 November 1995, having played 143 matches.


title: Martin Crowe

text: After his retirement, Crowe helped develop a local variation of cricket, called "Cricket Max", and became a television commentator and pundit. He was a board member of the South Sydney Rabbitohs Rugby League Football Club of which Russell Crowe is part owner. He was roped in as the CEO of the management team of Royal Challengers Bangalore, a team in the Indian Premier League. Midway through the season the owner Vijay Mallya expressed displeasure over the team and its performance in the league by sacking its bowling coach Venkatesh Prasad and mentor Charu Sharma blaming them for dismal team performance. Later in October of the same year, Crowe parted ways with the team and brought in Ray Jennings, the former coach of the South African National Cricket Team as the head coach of the team. Sources suggested that Mallya was unhappy with the team he had and held Crowe and his management team responsible for the debacle. He has also mentored current New Zealand batsmen, Martin Guptill, Ross Taylor and Kane Williamson. In 2014, he predicted and named Kane Williamson, Virat Kohli, Steve Smith and Joe Root in the young Fab Four list for test cricket.


title: Martin Crowe

text: On 19 May 2011, Crowe commented on Twitter that he wanted to improve his fitness by setting a goal to play first-class cricket again. He cited that he was only 3 first-class matches away from 250 matches, and 392 runs short of 20,000 runs.


title: Martin Crowe

text: Crowe took his first step to playing first-class cricket by playing at club level at the age of 49 (he was due to debut much earlier, but was delayed due to a groin injury). He played for the Cornwall reserve grade team, captaining them and batting at No.3 against Papatoetoe in a second-division club match in Auckland, the same club where his father played grade cricket.


title: Martin Crowe

text: On 15 October 2012, it was revealed that Crowe had been diagnosed with lymphoma. He blamed the illness on a failing immune system, which had been weakened by various illnesses picked up while touring India in the 1980s and 1990s.


title: Martin Crowe

text: On 5 June 2013, Crowe announced that he was free of cancer on "Campbell Live", but he would cut his ties with cricket, as he was a self-proclaimed "recovering addict to cricket, much like an alcoholic". Crowe says he wore a 'mask' from the age of 22, due to high expectations, but at the age of 51 was happy to 'look at the real me'.


title: Martin Crowe

text: In 2014, Crowe announced that the lymphoma had returned and subsequently indicated that his chances of survival beyond 12 months were less than 5% and also of his wish to see the 2015 Cricket World Cup in February and March 2015. He also attended the 2015 Cricket World Cup Final between Australia and New Zealand at the Melbourne Cricket Ground which in fact was his last public appearance.


title: Martin Crowe

text: Crowe died of complications from the disease in Auckland on 3 March 2016. His funeral was held in Holy Trinity Cathedral in a Christian ceremony in Parnell, Auckland.


title: Martin Crowe

text: In 1991, Crowe married Simone Curtice, an interior designer. They separated five years later, in 1996, and Crowe later entered into a relationship with Suzanne Taylor, with whom he had one daughter. He and Taylor separated in 2005. In 2009, Crowe married for a third time, to Lorraine Downes, a former Miss Universe. They remained married until his death.


title: Martin Crowe

text: Upon his death, Crowe was eulogised in "The Guardian" as "not just one of New Zealand’s greatest ever cricketers, but one of the most elegant batsmen the world has yet seen". A 2012 article by Mark Nicholas described him as "upright, orthodox and immensely strong" at the wicket, and praised the "speed and grace of the footwork" and "perfect head position". Nicholas thought the elegance of Crowe's batting was at odds with his physical size – he was "a big man in a small man's game". Writing in his retirement, Crowe emphasised the importance of instinct in batting, and the need to avoid premeditating a shot.


title: Martin Crowe

text: During his early career, Crowe was also often used as a "bits and pieces bowler", with his "lively in-swingers" faring especially well in English conditions. He was regarded as an "outstanding" fieldsman, and against Zimbabwe in the 1987 World Cup dismissed David Houghton with an outstretched diving catch that was said to have won New Zealand the game. As a captain, Crowe was known for his use of innovative techniques, most notably opening the bowling with a spinner, Dipak Patel, at the 1992 World Cup. He often had highly developed bowling and fielding plans, regularly rotating his bowlers and changing his fields to put pressure on opposing batsmen. Former Pakistan captain Rameez Raja described Crowe as "an imaginative leader who maximised his team's potential and resources by thoughtful captaincy and out-of-the-box tactics".


title: Relativity of simultaneity

text: In physics, the relativity of simultaneity is the concept that "distant simultaneity" – whether two spatially separated events occur at the same time – is not absolute, but depends on the observer's reference frame. This possibility was raised by mathematician Henri Poincaré in 1900, and thereafter became a central idea in the special theory of relativity.


title: Relativity of simultaneity

text: According to the special theory of relativity introduced by Albert Einstein, it is impossible to say in an "absolute" sense that two distinct events occur at the same time if those events are separated in space. If one reference frame assigns precisely the same time to two events that are at different points in space, a reference frame that is moving relative to the first will generally assign different times to the two events (the only exception being when motion is exactly perpendicular to the line connecting the locations of both events).


title: Relativity of simultaneity

text: For example, a car crash in London and another in New York appearing to happen at the same time to an observer on Earth, will appear to have occurred at slightly different times to an observer on an airplane flying between London and New York. Furthermore, if the two events cannot be causally connected, depending on the state of motion, the crash in London may appear to occur first in a given frame, and the New York crash may appear to occur first in another. However, if the events are causally connected, precedence order is preserved in all frames of reference.


title: Relativity of simultaneity

text: In 1892 and 1895, Hendrik Lorentz used a mathematical method called "local time" "t' = t – v x/c" for explaining the negative aether drift experiments. However, Lorentz gave no physical explanation of this effect. This was done by Henri Poincaré who already emphasized in 1898 the conventional nature of simultaneity and who argued that it is convenient to postulate the constancy of the speed of light in all directions. However, this paper does not contain any discussion of Lorentz's theory or the possible difference in defining simultaneity for observers in different states of motion.


title: Relativity of simultaneity

text: This was done in 1900, when Poincaré derived local time by assuming that the speed of light is invariant within the aether. Due to the "principle of relative motion", moving observers within the aether also assume that they are at rest and that the speed of light is constant in all directions (only to first order in "v/c"). Therefore, if they synchronize their clocks by using light signals, they will only consider the transit time for the signals, but not their motion in respect to the aether. So the moving clocks are not synchronous and do not indicate the "true" time. Poincaré calculated that this synchronization error corresponds to Lorentz's local time.


title: Relativity of simultaneity

text: In 1904, Poincaré emphasized the connection between the principle of relativity, "local time", and light speed invariance; however, the reasoning in that paper was presented in a qualitative and conjectural manner.


title: Relativity of simultaneity

text: Albert Einstein used a similar method in 1905 to derive the time transformation for all orders in "v/c", i.e., the complete Lorentz transformation. Poincaré obtained the full transformation earlier in 1905 but in the papers of that year he did not mention his synchronization procedure. This derivation was completely based on light speed invariance and the relativity principle, so Einstein noted that for the electrodynamics of moving bodies the aether is superfluous. Thus, the separation into "true" and "local" times of Lorentz and Poincaré vanishes – all times are equally valid and therefore the relativity of length and time is a natural consequence.


title: Relativity of simultaneity

text: In 1908, Hermann Minkowski introduced the concept of a world line of a particle in his model of the cosmos called Minkowski space. In Minkowski's view, the naïve notion of velocity is replaced with rapidity, and the ordinary sense of simultaneity becomes dependent on hyperbolic orthogonality of spatial directions to the worldline associated to the rapidity. Then every inertial frame of reference has a rapidity and a simultaneous hyperplane.


title: Relativity of simultaneity

text: In 1990 Robert Goldblatt wrote "Orthogonality and Spacetime Geometry", directly addressing the structure Minkowski had put in place for simultaneity. In 2006 Max Jammer, through Project MUSE, published "Concepts of Simultaneity: from antiquity to Einstein and beyond". The book culminates in chapter 6, "The transition to the relativistic conception of simultaneity". Jammer indicates that Ernst Mach demythologized the absolute time of Newtonian physics.


title: Relativity of simultaneity

text: Naturally the mathematical notions preceded physical interpretation. For instance conjugate diameters of a hyperbola, are related as space and time. The principle of relativity can be expressed as the arbitrariness of which pair are taken to represent space and time in a plane.


title: Relativity of simultaneity

text: Einstein's version of the experiment presumed that one observer was sitting midway inside a speeding traincar and another was standing on a platform as the train moved past. As measured by the standing observer, the train is struck by two bolts of lightning simultaneously, but at different positions along the axis of train movement (back and front of the train car). In the inertial frame of the standing observer, there are three events which are spatially dislocated, but simultaneous: standing observer facing the moving observer (i.e., the center of the train), lightning striking the front of the train car, and lightning striking the back of the car.


title: Relativity of simultaneity

text: Since the events are placed along the axis of train movement, their time coordinates become projected to different time coordinates in the moving train's inertial frame. Events which occurred at space coordinates in the direction of train movement happen "earlier" than events at coordinates opposite to the direction of train movement. In the moving train's inertial frame, this means that lightning will strike the front of the train car "before" the two observers align (face each other).


title: Relativity of simultaneity

text: A popular picture for understanding this idea is provided by a thought experiment similar to those suggested by Daniel Frost Comstock in 1910 and Einstein in 1917. It also consists of one observer midway inside a speeding traincar and another observer standing on a platform as the train moves past.


title: Relativity of simultaneity

text: A flash of light is given off at the center of the traincar just as the two observers pass each other. For the observer on board the train, the front and back of the traincar are at fixed distances from the light source and as such, according to this observer, the light will reach the front and back of the traincar at the same time.


title: Relativity of simultaneity

text: For the observer standing on the platform, on the other hand, the rear of the traincar is moving (catching up) toward the point at which the flash was given off, and the front of the traincar is moving away from it. As the speed of light is finite and the same in all directions for all observers, the light headed for the back of the train will have less distance to cover than the light headed for the front. Thus, the flashes of light will strike the ends of the traincar at different times.


title: Relativity of simultaneity

text: It may be helpful to visualize this situation using spacetime diagrams. For a given observer, the "t"-axis is defined to be a point traced out in time by the origin of the spatial coordinate "x", and is drawn vertically. The "x"-axis is defined as the set of all points in space at the time "t" = 0, and is drawn horizontally. The statement that the speed of light is the same for all observers is represented by drawing a light ray as a 45° line, regardless of the speed of the source relative to the speed of the observer.


title: Relativity of simultaneity

text: In the first diagram, the two ends of the train are drawn as grey lines. Because the ends of the train are stationary with respect to the observer on the train, these lines are just vertical lines, showing their motion through time but not space. The flash of light is shown as the 45° red lines. The points at which the two light flashes hit the ends of the train are at the same level in the diagram. This means that the events are simultaneous.


title: Relativity of simultaneity

text: In the second diagram, the two ends of the train moving to the right, are shown by parallel lines. The flash of light is given off at a point exactly halfway between the two ends of the train, and again form two 45° lines, expressing the constancy of the speed of light. In this picture, however, the points at which the light flashes hit the ends of the train are "not" at the same level; they are "not" simultaneous.


title: Relativity of simultaneity

text: The relativity of simultaneity can be demonstrated using the Lorentz transformation, which relates the coordinates used by one observer to coordinates used by another in uniform relative motion with respect to the first.


title: Relativity of simultaneity

text: Assume that the first observer uses coordinates labeled "t", "x", "y", and "z", while the second observer uses coordinates labeled "t′", "x′", "y′", and "z′". Now suppose that the first observer sees the second observer moving in the "x"-direction at a velocity "v". And suppose that the observers' coordinate axes are parallel and that they have the same origin. Then the Lorentz transformation expresses how the coordinates are related:


title: Relativity of simultaneity

text: where "c" is the speed of light. If two events happen at the same time in the frame of the first observer, they will have identical values of the "t"-coordinate. However, if they have different values of the "x"-coordinate (different positions in the "x"-direction), they will have different values of the "t"' coordinate, so they will happen at different times in that frame. The term that accounts for the failure of absolute simultaneity is the "vx"/"c".


title: Relativity of simultaneity

text: The equation "t′" = constant defines a "line of simultaneity" in the ("x′", "t′") coordinate system for the second (moving) observer, just as the equation "t" = constant defines the "line of simultaneity" for the first (stationary) observer in the ("x", "t") coordinate system. From the above equations for the Lorentz transform it can be seen that "t"' is constant if and only if "t" − "vx"/"c" = constant. Thus the set of points that make "t" constant are different from the set of points that makes "t' "constant. That is, the set of events which are regarded as simultaneous depends on the frame of reference used to make the comparison.


title: Relativity of simultaneity

text: Graphically, this can be represented on a spacetime diagram by the fact that a plot of the set of points regarded as simultaneous generates a line which depends on the observer. In the spacetime diagram, the dashed line represents a set of points considered to be simultaneous with the origin by an observer moving with a velocity "v" of one-quarter of the speed of light. The dotted horizontal line represents the set of points regarded as simultaneous with the origin by a stationary observer. This diagram is drawn using the ("x", "t") coordinates of the stationary observer, and is scaled so that the speed of light is one, i.e., so that a ray of light would be represented by a line with a 45° angle from the "x" axis. From our previous analysis, given that "v" = 0.25 and "c" = 1, the equation of the dashed line of simultaneity is "t" − 0.25"x" = 0 and with "v" = 0, the equation of the dotted line of simultaneity is "t" = 0.


title: Relativity of simultaneity

text: In general the second observer traces out a worldline in the spacetime of the first observer described by "t" = "x"/"v", and the set of simultaneous events for the second observer (at the origin) is described by the line "t" = "vx". Note the multiplicative inverse relation of the slopes of the worldline and simultaneous events, in accord with the principle of hyperbolic orthogonality.


title: Relativity of simultaneity

text: The Lorentz-transform calculation above uses a definition of extended-simultaneity (i.e. of when and where events occur "at which you were not present") that might be referred to as the co-moving or "tangent free-float-frame" definition. This definition is naturally extrapolated to events in gravitationally-curved spacetimes, and to accelerated observers, through use of a radar-time/distance definition that (unlike the tangent free-float-frame definition for accelerated frames) assigns a unique time and position to any event.


title: Relativity of simultaneity

text: The radar-time definition of extended-simultaneity further facilitates visualization of the way that acceleration curves spacetime for travelers in the absence of any gravitating objects. This is illustrated in the figure at right, which shows radar time/position isocontours for events in flat spacetime as experienced by a traveler (red trajectory) taking a constant proper-acceleration roundtrip. One caveat of this approach is that the time and place of remote events are not fully defined until light from such an event is able to reach our traveler.


title: Curtain wall (architecture)

text: A curtain wall is an outer covering of a building in which the outer walls are non-structural, utilized only to keep the weather out and the occupants in. Since the curtain wall is non-structural, it can be made of lightweight materials, such as glass, thereby potentially reducing construction costs. An additional advantage of glass is that natural light can penetrate deeper within the building. The curtain wall façade does not carry any structural load from the building other than its own dead load weight. The wall transfers lateral wind loads that are incident upon it to the main building structure through connections at floors or columns of the building. A curtain wall is designed to resist air and water infiltration, absorb sway induced by wind and seismic forces acting on the building, withstand wind loads, and support its own weight.


title: Curtain wall (architecture)

text: Curtain walls may be designed as "systems" integrating frame, wall panel, and weatherproofing materials. Steel frames have largely given way to aluminum extrusions, typically infilled with glass, which provides an architecturally pleasing look and benefits such as daylighting. However, the effects of light on visual comfort as well as solar heat gain in a building are more difficult to control when using large amounts of glass infill. Other common infills include stone veneer, metal panels, louvres, and operable windows or vents.


title: Curtain wall (architecture)

text: Curtain wall systems differ from storefront systems in being designed to span multiple floors, taking into consideration building sway and movement in addition to design requirements such as thermal expansion and contraction; seismic requirements; water diversion; and thermal efficiency for cost-effective heating, cooling, and interior lighting.


title: Curtain wall (architecture)

text: Their exterior walls were load bearing, supporting much or all of the load of the entire structure. The nature of the materials resulted in inherent limits to a building's height and the maximum size of window openings.


title: Curtain wall (architecture)

text: The development and widespread use of structural steel and later reinforced concrete allowed relatively small columns to support large loads. The exterior walls could be non-load bearing, and thus much lighter and more open than load-bearing walls of the past. This gave way to increased use of glass as an exterior façade, and the modern-day curtain wall was born.


title: Curtain wall (architecture)

text: Post and beam and balloon framed timber structures effectively had an early version of curtain walls, as their frames supported loads that allowed the walls themselves to serve other functions, such as keeping weather out and allowing light in. When iron began to be used extensively in buildings in late 18th-century Britain, such as at Ditherington Flax Mill, and later when buildings of wrought iron and glass such as The Crystal Palace were built, the building blocks of structural understanding were laid for the development of curtain walls.


title: Curtain wall (architecture)

text: Oriel Chambers (1864) and 16 Cook Street (1866), both built in Liverpool, England, by local architect and civil engineer Peter Ellis, are characterised by their extensive use of glass in their facades. Towards the courtyards they even boasted metal-framed glass curtain walls, which makes them two of the world's first buildings to include this architectural feature. The extensive glass walls allowed light to penetrate further into the building, utilizing more floor space and reducing lighting costs. Oriel Chambers comprises set over five floors without an elevator, which had only recently been invented and was not yet widespread. The Statue of Liberty (1886) features a thin, non-load-bearing copper skin.


title: Curtain wall (architecture)

text: An early example of an all-steel curtain wall used in the classical style is the ' department store on ', Berlin, built in 1901 (since demolished).


title: Curtain wall (architecture)

text: Some of the first curtain walls were made with steel mullions, and the polished plate glass was attached to the mullions with asbestos- or fiberglass-modified glazing compound. Eventually silicone sealants or glazing tape were substituted for the glazing compound. Some designs included an outer cap to hold the glass in place and to protect the integrity of the seals. The first curtain wall installed in New York City, in the United Nations Secretariat Building (Skidmore, Owings, and Merrill, 1952), was this type of construction. Earlier modernist examples are the Bauhaus in Dessau (1926) and the Hallidie Building in San Francisco (1918).


title: Curtain wall (architecture)

text: Ludwig Mies van der Rohe's curtain wall is one of the most important aspect of his architectural design. Mies first began prototyping the curtain wall in his high-rise residential building designs along Chicago's lakeshore, achieving the look of a curtain wall at famed 860-880 Lake Shore Drive Apartments. He finally perfected the curtain wall at 900 910 Lake Shore Drive, where the curtain is an autonomous aluminum and glass skin. After 900 910, Mies' curtain wall appeared on all of his subsequent high-rise building designs including the famed Seagram building in New York.


title: Curtain wall (architecture)

text: During the 1970s, the widespread use of aluminium extrusions for mullions began. Aluminum alloys offer the unique advantage of being able to be easily extruded into nearly any shape required for design and aesthetic purposes. Today, the design complexity and shapes available are nearly limitless. Custom shapes can be designed and manufactured with relative ease. The Omni San Diego Hotel curtain wall in California, designed by architectural firm Hornberger and Worstel and developed by JMI Realty, is an example of a unitized curtain-wall system with integrated sunshades.


title: Curtain wall (architecture)

text: The vast majority of ground-floor curtain walls are installed as long pieces (referred to as "sticks") between floors vertically and between vertical members horizontally. Framing members may be fabricated in a shop, but installation and glazing is typically performed at the jobsite.


title: Curtain wall (architecture)

text: Very similar to a stick system, a ladder system has mullions which can be split and then either snapped or screwed together consisting of a half box and plate. This allows sections of curtain wall to be fabricated in a shop, effectively reducing the time spent installing the system on site. The drawbacks of using such a system is reduced structural performance and visible joint lines down the length of each mullion.


title: Curtain wall (architecture)

text: Unitized curtain walls entail factory fabrication and assembly of panels and may include factory glazing. These completed units are installed on the building structure to form the building enclosure. Unitized curtain wall has the advantages of: speed; lower field installation costs; and quality control within an interior climate-controlled environment. The economic benefits are typically realized on large projects or in areas of high field labor rates.


title: Curtain wall (architecture)

text: A common feature in curtain wall technology, the rainscreen principle theorizes that equilibrium of air pressure between the outside and inside of the "rainscreen" prevents water penetration into the building. For example, the glass is captured between an inner and an outer gasket in a space called the glazing rebate. The glazing rebate is ventilated to the exterior so that the pressure on the inner and outer sides of the outer gasket is the same. When the pressure is equal across this gasket, water cannot be drawn through joints or defects in the gasket.


title: Curtain wall (architecture)

text: A curtain wall system must be designed to handle all loads imposed on it as well as keep air and water from penetrating the building envelope.


title: Curtain wall (architecture)

text: The loads imposed on the curtain wall are transferred to the building structure through the anchors which attach the mullions to the building.


title: Curtain wall (architecture)

text: "Dead load" is defined as the weight of structural elements and the permanent features on the structure. In the case of curtain walls, this load is made up of the weight of the mullions, anchors and other structural components of the curtain wall, as well as the weight of the infill material. Additional dead loads imposed on the curtain wall may include sunshades or signage attached to the curtain wall.


title: Curtain wall (architecture)

text: "Wind load" is a normal force acting on the building as the result of wind blowing on the building. Wind pressure is resisted by the curtain wall system since it envelops and protects the building. Wind loads vary greatly throughout the world, with the largest wind loads being near the coast in hurricane-prone regions. For each project location, building codes specify the required design wind loads. Often, a wind tunnel study is performed on large or unusually-shaped buildings. A scale model of the building and the surrounding vicinity is built and placed in a wind tunnel to determine the wind pressures acting on the structure in question. These studies take into account vortex shedding around corners and the effects of surrounding topography and buildings.


title: Curtain wall (architecture)

text: "Seismic loads" in curtain wall system are limited to the interstory drift induced on the building during an earthquake. In most situations, the curtain wall is able to naturally withstand seismic and wind induced building sway because of the space provided between the glazing infill and the mullion. In tests, standard curtain wall systems are typically able to withstand up to three inches (75 mm) of relative floor movement without glass breakage or water leakage.


title: Curtain wall (architecture)

text: "Snow loads" and live loads are not typically an issue in curtain walls, since curtain walls are designed to be vertical or slightly inclined. If the slope of a wall exceeds 20 degrees or so, these loads may need to be considered.


title: Curtain wall (architecture)

text: "Thermal loads" are induced in a curtain wall system because aluminum has a relatively high coefficient of thermal expansion. This means that over the span of a couple of floors, the curtain wall will expand and contract some distance, relative to its length and the temperature differential. This expansion and contraction is accounted for by cutting horizontal mullions slightly short and allowing a space between the horizontal and vertical mullions. In unitized curtain wall, a gap is left between units, which is sealed from air and water penetration by gaskets. Vertically, anchors carrying wind load only (not dead load) are slotted to account for movement. Incidentally, this slot also accounts for live load deflection and creep in the floor slabs of the building structure.


title: Curtain wall (architecture)

text: Accidental explosions and terrorist threats have brought on increased concern for the fragility of a curtain wall system in relation to blast loads. The bombing of the Alfred P. Murrah Federal Building in Oklahoma City, Oklahoma, has spawned much of the current research and mandates in regards to building response to blast loads. Currently, all new federal buildings in the U.S. and all U.S. embassies built on foreign soil must have some provision for resistance to bomb blasts.


title: Curtain wall (architecture)

text: Since the curtain wall is at the exterior of the building, it becomes the first line of defense in a bomb attack. As such, blast resistant curtain walls are designed to withstand such forces without compromising the interior of the building to protect its occupants. Since blast loads are very high loads with short durations, the curtain wall response should be analyzed in a dynamic load analysis, with full-scale mock-up testing performed prior to design completion and installation.


title: Curtain wall (architecture)

text: Blast resistant glazing consists of laminated glass, which is meant to break but not separate from the mullions. Similar technology is used in hurricane-prone areas for impact protection from wind-borne debris.


title: Curtain wall (architecture)

text: "Air infiltration" is the air which passes through the curtain wall from the exterior to the interior of the building. The air is infiltrated through the gaskets, through imperfect joinery between the horizontal and vertical mullions, through weep holes, and through imperfect sealing. The American Architectural Manufacturers Association (AAMA) is an industry trade group in the U.S. that has developed voluntary specifications regarding acceptable levels of air infiltration through a curtain wall.


title: Curtain wall (architecture)

text: "Water penetration" is defined as water passing from the exterior of the building to the interior of the curtain wall system. Sometimes, depending on the building specifications, a small amount of controlled water on the interior is deemed acceptable. Controlled water penetration is defined as water that penetrates beyond the inner most vertical plane of the test specimen, but has a designed means of drainage back to the exterior. AAMA Voluntary Specifications allow for controlled water penetration while the underlying ASTM E1105 test method would define such water penetration as a failure. To test the ability of a curtain wall to withstand water penetration in the field, an ASTM E1105 water spray rack system is placed on the exterior side of the test specimen, and a positive air pressure difference is applied to the system. This set up simulates a wind driven rain event on the curtain wall to check for field performance of the product and of the installation. Field quality control and assurance checks for water penetration has become the norm as builders and installers apply such quality programs to help reduce the number of water damage litigation suits against their work.


title: Curtain wall (architecture)

text: One of the disadvantages of using aluminum for mullions is that its modulus of elasticity is about one-third that of steel. This translates to three times more deflection in an aluminum mullion compared to a similar steel section under a given load. Building specifications set deflection limits for perpendicular (wind-induced) and in-plane (dead load-induced) deflections. These deflection limits are not imposed due to strength capacities of the mullions. Rather, they are designed to limit deflection of the glass (which may break under excessive deflection), and to ensure that the glass does not come out of its pocket in the mullion. Deflection limits are also necessary to control movement at the interior of the curtain wall. Building construction may be such that there is a wall located near the mullion, and excessive deflection can cause the mullion to contact the wall and cause damage. Also, if deflection of a wall is quite noticeable, public perception may raise undue concern that the wall is not strong enough.


title: Curtain wall (architecture)

text: Deflection limits are typically expressed as the distance between anchor points divided by a constant number. A deflection limit of L/175 is common in curtain wall specifications, based on experience with deflection limits that are unlikely to cause damage to the glass held by the mullion. Say a given curtain wall is anchored at 12 foot (144 in) floor heights. The allowable deflection would then be 144/175 = 0.823 inches, which means the wall is allowed to deflect inward or outward a maximum of 0.823 inches at the maximum wind pressure. However, some panels require stricter movement restrictions, or certainly those that prohibit a torque-like motion.


title: Curtain wall (architecture)

text: Deflection in mullions is controlled by different shapes and depths of curtain wall members. The depth of a given curtain wall system is usually controlled by the area moment of inertia required to keep deflection limits under the specification. Another way to limit deflections in a given section is to add steel reinforcement to the inside tube of the mullion. Since steel deflects at one-third the rate of aluminum, the steel will resist much of the load at a lower cost or smaller depth.


title: Curtain wall (architecture)

text: Deflection in curtainwall mullions also differs from deflection of the building structure, whether concrete, steel, or timber. Curtainwall anchors must be designed to allow differential movement between the building structure and the curtainwall.


title: Curtain wall (architecture)

text: Strength (or maximum usable stress) available to a particular material is not related to its material stiffness (the material property governing deflection); it is a separate criterion in curtain wall design and analysis. This often affects the selection of materials and sizes for design of the system. The allowable bending strength for certain aluminum alloys, such as those typically used in curtain wall framing, approaches the allowable bending strength of steel alloys used in building construction.


title: Curtain wall (architecture)

text: Relative to other building components, aluminum has a high heat transfer coefficient, meaning that aluminum is a very good conductor of heat. This translates into high heat loss through aluminum (or steel) curtain wall mullions.


title: Curtain wall (architecture)

text: There are several ways to compensate for this heat loss, the most common way being the addition of thermal breaks. "Thermal breaks" are barriers between exterior metal and interior metal, usually made of polyvinyl chloride (PVC). These breaks provide a significant decrease in the thermal conductivity of the curtain wall. However, since the thermal break interrupts the aluminum mullion, the overall moment of inertia of the mullion is reduced and must be accounted for in the structural analysis and deflection analysis of the system.


title: Curtain wall (architecture)

text: Thermal conductivity of the curtain wall system is important because of heat loss through the wall, which affects the heating and cooling costs of the building. On a poorly performing curtain wall, condensation may form on the interior of the mullions. This could cause damage to adjacent interior trim and walls.


title: Curtain wall (architecture)

text: Thermally-broken mullions with double or triple-glazed IGUs are often referred to as "high-performance" curtainwalls. While these curtainwall systems are more energy efficient than older, single glazed versions, they are still significantly less efficient than opaque (solid) wall construction. For example, nearly all curtainwall systems, thermally-broken or otherwise, have a U-value of 0.2 or higher, which is equivalent to an R-value of 5 or lower.


title: Curtain wall (architecture)

text: "Infill" refers to the large panels that are inserted into the curtain wall between mullions. Infills are typically glass but may be made up of nearly any exterior building element. Some common infills include metal panels, louvers, and photovoltaic panels. Infills are also referred to as spandrels or spandrel panels.


title: Curtain wall (architecture)

text: Float glass is by far the most common curtain wall glazing type. It can be manufactured in an almost infinite combination of color, thickness, and opacity. For commercial construction, the two most common thicknesses are 1/4 inch (6 mm) monolithic and 1 inch (25 mm) insulating glass. 1/4 inch glass is typically used only in spandrel areas, while insulating glass is used for the rest of the building (sometimes spandrel glass is specified as insulating glass as well). The 1 inch insulation glass is typically made up of two 1/4-inch lites of glass with a 1/2 inch (12 mm) airspace. The air inside is usually atmospheric air, but some inert gases, such as argon or krypton may be used to offer better thermal transmittance values. In Europe, triple-pane insulating glass infill is now common. In Scandinavia first curtain walls with quadruple-pane have been built.


title: Curtain wall (architecture)

text: Larger thicknesses are typically employed for buildings or areas with higher thermal, relative humidity, or sound transmission requirements, such as laboratory areas or recording studios. In residential construction, thicknesses commonly used are 1/8 inch (3 mm) monolithic and 5/8 inch (16 mm) insulating glass.


title: Curtain wall (architecture)

text: Glass may be used which is transparent, translucent, or opaque, or in varying degrees thereof. "Transparent" glass usually refers to "vision" glass in a curtain wall. Spandrel or vision glass may also contain translucent glass, which could be for security or aesthetic purposes. "Opaque" glass is used in areas to hide a column or spandrel beam or shear wall behind the curtain wall. Another method of hiding spandrel areas is through "shadow box" construction (providing a dark enclosed space behind the transparent or translucent glass). Shadow box construction creates a perception of depth behind the glass that is sometimes desired.


title: Curtain wall (architecture)

text: Thin blocks (3 to 4 inches (75–100 mm)) of stone can be inset within a curtain wall system. The type of stone used is limited only by the strength of the stone and the ability to manufacture it in the proper shape and size. Common stone types used are: calcium silicate, granite, marble, travertine, limestone, and engineered stone. To reduce weight and improve strength, the natural stone may be attached to an aluminum honeycomb backing.


title: Curtain wall (architecture)

text: Metal panels can take various forms including stainless steel, aluminum plate; aluminum composite panels consisting of two thin aluminum sheets sandwiching a thin plastic interlayer; copper wall cladding, and panels consisting of metal sheets bonded to rigid insulation, with or without an inner metal sheet to create a sandwich panel. Other opaque panel materials include fiber-reinforced plastic (FRP) and terracotta. Terracotta curtain wall panels were first used in Europe, but only a few manufacturers produce high quality modern terracotta curtain wall panels.


title: Curtain wall (architecture)

text: A louver is provided in an area where mechanical equipment located inside the building requires ventilation or fresh air to operate. They can also serve as a means of allowing outside air to filter into the building to take advantage of favorable climatic conditions and minimize the usage of energy-consuming HVAC systems. Curtain wall systems can be adapted to accept most types of louver systems to maintain the same architectural sightlines and style while providing desired functionality.


title: Curtain wall (architecture)

text: Most curtain wall glazing is fixed, meaning there is no access to the exterior of the building except through doors. However, windows or vents can be glazed into the curtain wall system as well, to provide required ventilation or operable windows. Nearly any window type can be made to fit into a curtain wall system.


title: Curtain wall (architecture)

text: Firestopping at the "perimeter slab edge", which is a gap between the floor and the curtain wall, is essential to slow the passage of fire and combustion gases between floors. Spandrel areas must have non-combustible insulation at the interior face of the curtain wall. Some building codes require the mullion to be wrapped in heat-retarding insulation near the ceiling to prevent the mullions from melting and spreading the fire to the floor above. The firestop at the perimeter slab edge is considered a continuation of the fire-resistance rating of the floor slab. The curtain wall itself, however, is not ordinarily required to have a rating. This causes a quandary as compartmentalization (fire protection) is typically based upon "closed" compartments to avoid fire and smoke migrations beyond each engaged compartment. A curtain wall by its very nature prevents the completion of the compartment (or envelope). The use of fire sprinklers has been shown to mitigate this matter. As such, unless the building is sprinklered, fire may still travel up the curtain wall, if the glass on the exposed floor is shattered from heat, causing flames to lick up the outside of the building.


title: Curtain wall (architecture)

text: Falling glass can endanger pedestrians, firefighters and firehoses below. An example of this is the 1988 First Interstate Tower fire in Los Angeles, California. The fire leapfrogged up the tower by shattering the glass and then consuming the aluminum framing holding the glass. Aluminum's melting temperature is 660 °C, whereas building fires can reach 1,100 °C. The melting point of aluminum is typically reached within minutes of the start of a fire.


title: Curtain wall (architecture)

text: Fireman knock-out glazing panels are often required for venting and emergency access from the exterior. Knock-out panels are generally fully tempered glass to allow full fracturing of the panel into small pieces and relatively safe removal from the opening.


title: Curtain wall (architecture)

text: Curtain walls and perimeter sealants require maintenance to maximize service life. Perimeter sealants, properly designed and installed, have a typical service life of 10 to 15 years. Removal and replacement of perimeter sealants require meticulous surface preparation and proper detailing.


title: Curtain wall (architecture)

text: Aluminum frames are generally painted or anodized. Care must be taken when cleaning areas around anodized material as some cleaning agents will destroy the finish. Factory applied fluoropolymer thermoset coatings have good resistance to environmental degradation and require only periodic cleaning. Recoating with an air-dry fluoropolymer coating is possible but requires special surface preparation and is not as durable as the baked-on original coating. Anodized aluminum frames cannot be "re-anodized" in place but can be cleaned and protected by proprietary clear coatings to improve appearance and durability.


title: Curtain wall (architecture)

text: Stainless steel curtain walls require no coatings, and embossed, as opposed to abrasively finished, surfaces maintain their original appearance indefinitely without cleaning or other maintenance. Some specially textured matte stainless steel surface finishes are hydrophobic and resist airborne and rain-borne pollutants. This has been valuable in the American Southwest and in the Mideast for avoiding dust, as well as avoiding soot and smoke staining in polluted urban areas.


title: Dear White People

text: Dear White People is a 2014 American satirical dark comedy-drama film written, directed and co-produced by Justin Simien. The film focuses on escalating racial tensions at a fictitious, prestigious Ivy League college from the perspective of several black students. It stars Tyler James Williams, Tessa Thompson, Kyle Gallner, Teyonah Parris, Brandon P. Bell, Brittany Curran, Marque Richardson and Dennis Haysbert.


title: Dear White People

text: The film premiered in competition in the "US Dramatic Category" at 2014 Sundance Film Festival on January 18, 2014. The film had a theatrical release in United States on October 17, 2014. A commercial and critical success, the film profited at the box office and received positive reviews from many professional critics. It has also been nominated for and has received several awards.


title: Dear White People

text: In 2017, the film was adapted into a Netflix series of the same name, also with Simien's involvement. Like the film, the series has also enjoyed critical acclaim.