A harbor or harbour (see spelling differences), or haven, is a body of water where ships, boats and barges seek shelter from stormy weather, or are stored for future use. Harbors and ports are often confused with each other. A port is a facility for loading and unloading vessels; ports are often located in harbors.
Harbors can be natural or artificial. An artificial harbor 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 harbor is Long Beach Harbor, California, 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 harbor is surrounded on several sides by prominences of land. Examples of natural harbors include Sydney Harbour, Australia and San Francisco Bay, California.
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 BC, reign of King Khufu). The largest artificially created harbor is Jebel Ali in Dubai. Other large and busy artificial harbors include: