Aniakchak National Monument and Preserve  

Extreme isolation and severe weather keep all but a few hardy adventurers from exploring this natural wonder, with its 30-square mile volcanic caldera. Inside that huge volcanic bowl, Vent Mountain is building up part of the enormous area that collapsed after earlier eruptions. Geothermally-warmed water from Surprise Lake spills down a 1500 foot rift in the crater wall to form the Aniakchak River. An active volcano, Aniakchak last erupted in 1931.

Size: 600,000 acres. Located near the top of the Aleutian Chain, about 200 miles southwest of Kodiak. Proclaimed a national monument in 1978 by President Jimmy Carter. Expanded to include the preserve in the 1980 Alaska lands act.

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