Circle Icefall (79°38′S 156°30′E) is an almost impenetrable icefall near Tentacle Ridge, 45 metres (150 ft) high and 15 nautical miles (28 km) long, extending in an arc for almost the whole width across the Darwin Glacier. It was named by the Darwin Glacier Party of the Commonwealth Trans-Antarctic Expedition (1956–58) for its similarity to the circle of an opera house.
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Circle Icefall Wikipedia(Text) CC BY-SA