coral atoll in the Central and Southern Line Islands, part of Kiribati, southwestern Pacific Ocean. It is situated 1,700 miles (2,700 km) south of Hawaii. A level formation with a land area of 11 square miles (28 square km) and a large lagoon, it has temple platforms and graves that indicate several generations of habitation by Polynesians before Europeans arrived. The atoll was first sighted in 1825 by a British naval officer, George Anson Byron. During the second half of the 19th century, when its guano deposits were being worked, the island was claimed by the United States under the Guano Act of 1856. The deposits were exhausted by the 1920s. Malden Island was used (1956–64) by the British for nuclear weapons testing along with nearby Kiritimati Atoll. The island became a part of the Gilbert and Ellice Islands Colony in 1972 and a part of independent Kiribati in 1979. Malden Island is a breeding ground for several large populations of seabirds and was designated a wildlife sanctuary and reserve in 1975. It has no inhabitants.