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.
Roger Federer held the ATP No. 1 position for a record 237 consecutive weeks from 2 February 2004 to 18 August 2008. Arguably the greatest tennis player ever, the Federer era may be nearing its end. He has been passed by both Rafael Nadal and Novak Djokovic in the rankings.