A view of Unimak Island, Alaska from the space shuttle. Unimak is the largest island in the Aleutian chain. The major volcano on the island (snow-capped peak at the center of the photograph), Shishaldin, rises approximately 2,860 m (9,400 ft) and has been active during the last 200 years. The volcano is known locally as “Smoking Moses.” At the southwestern end of the island (top) is the snow-capped Pogromni Volcano. The blue lake situated in a large volcanic caldera, which can be seen midway between the Pogromni and Shishaldin volcanoes, is the result of a now extinct volcano that collapsed. Image courtesy of NASA.