Lake Vostok

A freshwater lake 250 km long and 50 km wide, about 12,500 square kilometres, sitting under four kilometres of ice and 500 metres below sea level. It may have been sealed off for 15 to 25 million years, which makes it one of the most isolated bodies of water anywhere. Russian drillers reached the surface of it on 6 February 2012 after a core 3,768 metres deep, and the moment they did the pressurised lake water came up the borehole and mixed with the Freon and kerosene used to stop the hole freezing. Environmental groups had argued for hot-water drilling for that exact reason. Gene sequencing found 3,507 unique sequences, about 94 percent bacterial and 6 percent eukaryote, but the contamination makes the result genuinely hard to read, and that is the honest state of it. Under Vostok Station, East Antarctica.