Harbor

A harbour (British English) or harbor (American English); (see spelling differences) (synonym: haven) is a sheltered body of water where ships, boats, and barges can be docked. The term "harbour" is often used interchangeably with "port", which is a man-made facility built for loading and unloading vessels and dropping off and picking up passengers. Ports usually include one or more harbours. Alexandria Port in Egypt is an example of a port with two harbours.
Harbours may be natural or artificial. An artificial harbour can have deliberately constructed breakwaters, sea walls, or jettys or they can be constructed by dredging, which requires maintenance by further periodic dredging. An example of an artificial harbour is Long Beach Harbor, California, United States, which was an array of salt marshes and tidal flats too shallow for modern merchant ships before it was first dredged in the early 20th century. In contrast, a natural harbour is surrounded on several sides by prominences of land. Examples of natural harbours include Sydney Harbour, Australia and Trincomalee Harbour in Sri Lanka.
Artificial harbours.
Artificial harbours are frequently built for use as ports. The oldest artificial harbour known is the Ancient Egyptian site at Wadi al-Jarf, on the Red Sea coast, which is at least 4500 years old (ca. 2600-2550 BCE, reign of King Khufu). The largest artificially created harbour is Jebel Ali in Dubai. Other large and busy artificial harbors include:
The Ancient Carthaginians constructed fortified, artificial harbours called cothons.
Natural harbours.
A natural harbour is a landform where a section of a body of water is protected and deep enough to allow anchorage. Many such harbours are rias. Natural harbours have long been of great strategic naval and economic importance, and many great cities of the world are located on them. Having a protected harbour reduces or eliminates the need for breakwaters as it will result in calmer waves inside the harbour. Some examples are:
Ice-free harbours.
For harbours near the North and South Poles, being ice-free is an important advantage, especially when it is year-round. Examples of these are:
The world's southernmost harbour, located at Antarctica's Winter Quarters Bay (77° 50′ South), is sometimes ice-free, depending on the summertime pack ice conditions.
Important harbours.
Although the world's busiest port is a contested title, in 2006 the world's busiest harbor by cargo tonnage was the Port of Shanghai.
The following are large natural harbors: