Southern portion of Onekotan, an uninhabited volcanic island in Russia’s Kuril Islands chain. Onekotan’s 7.5-kilometer-wide Tao-Rusyr Caldera was formed ca. 7,500 years ago and is filled by the waters of Kal'tsevoe Lake. The lake in turn contains the 4-kilometer-wide Krenitzyn Peak, a post-caldera cone whose summit is the highest point on Onekotan. This satellite image of an “island within an island” was taken on 31 May 2009. Courtesy NASA.