Alexander Island

Island in Bellingshausen Sea, separated from the Antarctic mainland by George VI Sound. An extremely rugged region with peaks as high as 9,800 ft (3,000 m), it is 270 mi (435 km) long and up to 125 mi (200 km) wide, with an area of 16,700 sq mi (43,250 sq km). The Russian explorer F.G. von Bellingshausen discovered the land in 1821 and named it after Tsar Alexander. It was believed part of the mainland until 1940, when a U.S. expedition proved it to be an island, connected to the continent by a huge floating ice shelf. It has been claimed by Britain (since 1908), Chile (1940), and Argentina (1942).