For 15 million years, a vast icebound lake has been sealed deep beneath Antarctica's frozen crust, possibly hiding prehistoric or other unknown life. Now Russian scientists are on the brink of piercing through to its secrets. They suspect its depths will reveal new life forms, show how the planet was before the ice age and how life evolved. It could even offer a glimpse at what conditions for life exist in the similar extremes of Mars and Jupiter's moon Europa. The Antarctic's subglacial lakes are the last great unexplored habitat on earth, and Lake Vostok is the largest of them.