But when the question of how to explore the lake came up, not long after its discovery, the Vostok scientists faced a serious dilemma. The lake is under immense pressure, and to breach the ice would have devastating consequences.
Roger Federer: Swiss star will play on until at least 2019. Updated 1815 GMT (0215 HKT) February 21, 2017. Chat with us in Facebook Messenger. Find out what's happening in the world as it unfolds.
Video: Federer and Murray Play Match for Africa 3 in Zurich. Roger Federer and Andy Murray played a few sets in Zurich for a good cause on Monday. Murray Not Sure about Playing Monte-Carlo Yet. The World No.1 is progressing in his recovery from an elbow injury, but still can't serve at full speed.