On February 5th, more than twenty years after they first started drilling, Russian scientists finally broke through the last remaining layers of an ice sheet that has separated Lake Vostok from the rest of the world for twenty million years.
But when Russian scientists first began boring their way through the ice above Vostok, they had no idea that the Earth's third largest body of water was lurking nearly 4,000 meters beneath their feet. In fact, the research started out as an expedition to recover ice cores for use in climate studies.
By the late nineties, however, scientists had verified that there was, in fact, a massive subglacial lake beneath the borehole; yet fear of contaminating the lake meant that plowing through to its surface was entirely out of the question. So in 1998, less than 200 meters from Vostok's waters, drilling stopped entirely.
Those figures are pretty incredible if you think about them. Take a look at this diagram, borrowed from a great writeup over on Nature News. The figure doubles as a timeline for the events leading up to the breach in Vostok's ice/water boundary. As the graphic indicates, the researchers started drilling in 1990. That means that almost 95% of the vertical trip to Vostok through the Antarctic ice sheet was actually completed by 1998. The hard part was closing the deal — the last couple hundred meters took 14 years.