Astronaut photo of Kingman Reef, a largely submerged, uninhabited triangular structure in the North Pacific Ocean, roughly halfway between the Hawaiian Islands and American Samoa. The reef lagoon is 82 m (270 ft) deep at the western part and the total enclosed area is about 76 sq km (29 sq mi). The east-west and northwest-southeast trending small strips of dry land are composed of coral rubble and giant clamshells. The highest point on the reef is less than 1.5 m (5 ft) above sea level, which is awash most of the time, making Kingman Reef a maritime hazard. Image courtesy of NASA.