The Chagos archipelago lies 6 degrees south 72 degrees east. There are over 50 islands, all of which are uninhabited except for Diego Garcia. In the 16th century, when the Portuguese began sailing more directly across the Indian Ocean, they discovered these islands. In the 18th century a copra industry was developed by a French colony. In 1814 the archipelago was ceded to Britain. 1965 they became part of British Indian Ocean Territory. In 1966 Britain and the U.S. came to an agreement to make the territory available for defense purposes. In 1967 the Crown purchased the islands. There are 3000 military and civilian personnel stationed on the island of Diego Garcia. The archipelago has the largest expanse of undisturbed coral reefs in the Indian Ocean. They have strict conservation rules to protect the rare species of birds found among these islands.