Breakwater

Breakwater, barrier, either natural or artificial, that extends into the open water of a sea or lake to break the force of the waves and provide calm water in a harbour. Natural breakwaters are offshore islands and promontories that shelter the shore from waves. Artificial breakwaters may be attached to the land or separated from it and have been constructed in various shapes and sizes. They can be built of stones and rubble, of masonry, or of a combination. Floating breakwaters, securely moored so that they do not ride too readily on the waves, are sometimes used. Breakwaters, first constructed by the ancient Greeks and Romans, are used throughout the world.