It sometimes seems as if our planet has no secrets left - but deep beneath the great Antarctic ice sheet scientists have made an astonishing discovery. They’ve found one of the largest lakes in the world. It’s very existence defies belief. Scientists are desperate to get into the lake because its extreme environment may be home to unique flora and fauna, never seen before, and NASA are excited by what it could teach us about extraterrestrial life. But 4 kilometres of ice stand between the lake and the surface, and breaking this seal without contaminating the most pristine body of water on the planet is possibly one of the greatest challenges science faces in the 21st century. In 1957 the Russians established a remote base in Antarctica - the Vostok station. It soon became a byword for hardship - dependent on an epic annual 1000km tractor journey from the coast for its supplies. The coldest temperature ever found on Earth (-89°C) was recorded here on the 21st July 1983. It’s an unlik