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.
Wimbledon 2015 TV schedule: When, where and who to watch, every day. Roger Federer holds up the Wimbledon trophy in 2006 after winning his fourth straight title at the tournament. The world wants one last Wimbledon triumph for 33-year-old Roger Federer.