Artificial harbors are frequently built for use as ports. The oldest artificial harbor 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 harbor is Jebel Ali in Dubai.2 Other large and busy artificial harbors include:
The Ancient Carthaginians constructed fortified, artificial harbors called cothons.
See also: List of deepest natural harbours
A natural harbor is a landform where a section of a body of water is protected and deep enough to allow anchorage. Many such harbors are rias. Natural harbors have long been of great strategic naval and economic importance, and many great cities of the world are located on them. Having a protected harbor reduces or eliminates the need for breakwaters as it will result in calmer waves inside the harbor. Some examples are:
For harbors 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 harbor, located at Antarctica's Winter Quarters Bay (77° 50′ South), is sometimes ice-free, depending on the summertime pack ice conditions.3
Although the world's busiest port is a contested title, in 2017 the world's busiest harbor by cargo tonnage was the Port of Ningbo-Zhoushan.4
The following are large natural harbors:
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Hattendorf, John B. (2007), The Oxford encyclopedia of maritime history, Oxford University Press, p. 590, ISBN 978-0-19-513075-1 978-0-19-513075-1 ↩
U.S. Polar Programs Archived 2021-10-11 at the Wayback Machine National Science Foundation FY2000. https://www.nsf.gov/about/budget/fy2000/00OPP.htm ↩
"Global Port Development Annual Report (2017)". Archived from the original on 2021-01-08. Retrieved 2021-10-29. https://web.archive.org/web/20210108235229/http://en.sisi-smu.org/index.php?c=article&id=16280 ↩