Guam ( /ˈɡwɑːm/ (help·info) ;Chamorro :Guåhan ) is an island in the western Pacific Ocean and is an organized, unincorporated territory of the United States. It is one of five U.S. territories with an established civilian government. - - The island's capital is Hagåtña (formerly Agana). Guam is the largest and southernmost of the Mariana Islands. The Chamorros, Guam's indigenous people, first populated the island approximately 4,000 years ago.5 - The island has a long history of European colonialism. First discovered by Europeans on March 6, 1521, by Ferdinand Magellan, the first colony was established in 1668 by Spain with the arrival of settlers including Padre San Vitores, a Catholic missionary. The island was controlled by Spain until 1898, when it was surrendered to the United States as part of the Treaty of Paris following the Spanish-American War. As the largest island in Micronesia and the only US-held island in the region before World War II, Guam was captured by the Japanese on December 8, 1941, hours after the bombing of Pearl Harbor, and was occupied for two and a half years. During the occupation, the people of Guam suffered terrible atrocities6 - including torture, beheadings, and rape, and were forced to adopt the Japanese culture. The Japanese occupation also imposed a new name, Ō-miya Jima or Great Shrine Island, on the island. Guam was subject to fierce fighting when US troops recaptured the island on July 21, 1944, a date commemorated every year as Liberation Day.7 - Today, Guam's economy is supported by its principal industry, tourism, which is primarily composed of visitors from Japan. Guam's second-largest source of income is the United States military.8 -