Shipwreck sites are locations where a ship has been wrecked or sunk, often due to natural disasters or human error. REEF is a term used to describe a ridge of rocks or coral that lies at or near the surface of the water. Seafloor is the bottom of the ocean, which can be made up of sand, mud, rock, and other materials. ISLE is another word for island, which is a landmass surrounded by water. Together, these three terms form the phrase 'shipwreck site, ' which describes a location where a ship has been wrecked or sunk.