A harbor structure is a type of man-made structure built along the shoreline of a body of water to provide access to ships and boats. The most common types of harbor structures are wharfs, quays, piers, and docks. A WHARF is a long platform built along the shoreline of a harbor or river, typically made of wood or stone. A QUAY is a structure built along the shoreline of a harbor or river, typically made of concrete or stone, used for loading and unloading ships. A PIER is a structure built out into the water from the shoreline, typically made of wood or concrete, used for docking ships. A DOCK is a structure built along the shoreline of a harbor or river, typically made of wood or concrete, used for mooring ships.