Lake Vostok is the world’s largest known subglacial lake and lies beneath the East Antarctic Ice Sheet. Hidden under roughly four kilometres of ice near Russia’s Vostok Station, it contains liquid freshwater in a basin sealed away from the surface environment.
The lake is approximately 250 kilometres long and 50 kilometres wide, with an estimated surface area of about 12,500 square kilometres. Its water may have been isolated beneath the ice for millions of years, making it important to scientists studying extreme environments, ancient climate, and the possibility of life in dark, high-pressure habitats.
Evidence for the lake emerged from seismic surveys in the 1950s and 1960s, while airborne radar and satellite measurements later confirmed its scale and shape. In February 2012, Russian researchers drilled through the ice into the lake. Scientists recovered lake-ice material in 2013, although concerns were raised about contamination from drilling fluids. Lake Vostok is not a visible surface lake like Lake Ellsworth or Lake Whillans; “subglacial” means it is buried beneath the Antarctic ice sheet.