A commonwealth in political union with the United States comprising most of the Mariana Islands (except Guam) in the western Pacific Ocean. The islands were part of the U.S. Trust Territory of the Pacific Islands from 1947 to 1978, when they became internally self-governing. The largest island, which serves as the capital, is Saipan. Population: 52,284. Self-governing commonwealth (pop., 2002 est.: 70,000) in political union with the U.S., in the western Pacific Ocean. Composed of 22 islands north of Guam, the Northern Marianas extend 450 mi (720 km) and have an area of 184 sq mi (477 sq km). The capital, Chalan Kanoa, is on Saipan. Saipan, Tinian, and Rota are the principal inhabited islands. Others include Alamagan and Agrihan; Pagan was evacuated for a time after a 1981 volcanic eruption. The indigenous people are Micronesian; other inhabitants are Chamorro and Filipino. The islands were discovered by Ferdinand Magellan in 1521. They were colonized by Spain in 1668. Sold by Spain to Germany in 1899, they were occupied by Japan in 1914 and became a Japanese mandate from the League of Nations after 1919. They were the scene of fierce fighting in World War II; Tinian was the base for U.S. planes that dropped atomic bombs on Hiroshima and Nagasaki. The Northern Marianas were granted to the U.S. in 1947 as a UN trust territory, became self-governing in 1978, and became a commonwealth under U.S. sovereignty in 1986, when the residents became U.S. citizens. The UN trusteeship ended in 1990