Harbour

Harbors may be natural or artificial. An artificial harbor can have breakwaters, sea walls, or jetties, 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, United States, which was previously 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 naturally-occurring land. Examples of natural harbors include Victoria Harbour in Hong Kong, Sydney Harbour in New South Wales, Australia, Halifax Harbour in Nova Scotia, Canada, and Trincomalee Harbour in Sri Lanka.