The Chagos Archipelago ( or ) or Chagos Islands (formerly the Bassas de Chagas, and later the Oil Islands) is a group of seven atolls comprising more than 60 individual tropical islands in the Indian Ocean about south of the Maldives archipelago. This chain of islands is the southernmost archipelago of the Chagos-Laccadive Ridge, a long submarine mountain range in the Indian Ocean. The Chagos forms a terrestrial ecoregion together with the Maldives and the Lakshadweep. The islands and their surrounding waters are a vast oceanic Environment Preservation and Protection Zone (EPPZ) (Fisheries Conservation and Management Zone (FCMZ) of ), an area twice the size of the UK's land surface.