Amchitka (; ; ) is a volcanic, tectonically unstable and uninhabited island in the Rat Islands group of the Aleutian Islands in southwest Alaska. It is part of the Alaska Maritime National Wildlife Refuge. The island, with a land area of roughly , is about long and wide. The area has a maritime climate, with many storms, and mostly overcast skies. Amchitka was populated for more than 2,500 years by the Aleut people, but has had no permanent population since 1832. The island has been part of the United States since the Alaska Purchase of 1867. During World War II, it was used as an airfield by US forces in the Aleutian Islands Campaign. Amchitka was selected by the United States Atomic Energy Commission to be the site for underground detonations of nuclear weapons. Three such tests were carried out: Long Shot, an blast in 1965; Milrow, a blast in 1969; and Cannikin in 1971 – at , the largest underground test ever conducted by the United States. The tests were highly controversial, with environmental groups fearing that the Cannikin explosion, in particular, would cause severe earthquakes and tsunamis. Amchitka is no longer used for nuclear testing. It is still monitored for the leakage of radioactive materials. Geography Amchitka is the southernmost of the Rat Islands group in the Aleutian Chain, located between and . It is bounded by the Bering Sea to the north and east, and the Pacific Ocean to the south and west. The eastern part of the island is a lowland plateau, with isolated ponds and gently rolling hills. There is low but abundant vegetation, consisting of mosses, lichens, liverworts, ferns, grasses, sedges, and crowberry. The center of the island is mountainous, and the western end is barren and vegetation is sparse. Amchitka has a maritime climate, often foggy and windswept, with cloud cover 98 percent of the time. While temperatures are moderated by the ocean, storms are frequent. Geologically, the island is volcanic, being a part of a small crustal block on the Aleutian Arc that is being torn apart by oblique subduction. It is "one of the least stable tectonic environments in the United States." Early history The human history of Amchitka dates back at least 2,500 years, with the Aleut people. Human remains, thought to be of an Aleut dating from about 1000 AD, were discovered in 1980. Amchitka is said to have