Funafuti (fōōnäfōō´tē), capital and chief atoll of Tuvalu, S Pacific. It comprises 30 islets of a reef 13 mi (21 km) long, with a land area of c.1 sq mi (2.6 sq km). The islet of Fongafale is the most populous part of the atoll; the center of government is there. The atoll was discovered in 1819 and became part of a British colony in 1915. An expedition led by Sir Edgeworth David in 1897 proved the Darwinian theory of atoll formation (see coral reefs) by sinking a 1,100 ft (335 m) bore into the island.