The British Indian Ocean Territory (BIOT) lies about 1,770km east of Mahe (the main island of the Seychelles). The territory, an archipelago of 58 islands sometimes referred to as the Chagos Archipelago, covers some 640,000 sq km of ocean. The islands have a land area of only 60 sq km and 698km of coastline. Diego Garcia, the largest and most southerly island, is 44 sq km. The climate is hot, humid and moderated by trade winds. The terrain is flat and low and most areas do not exceed two metres in elevation.