Antarctic Mysteries

Antarctica holds about 70% of Earth's fresh water in ice up to 4.8 kilometers thick. If it all melted, sea levels would rise by roughly 58 meters, submerging most coastal cities.

Beneath the ice, scientists have mapped hundreds of subglacial lakes, kept liquid by geothermal heat and the pressure of the ice above. Lake Vostok, sealed off for millions of years, may hold life found nowhere else. Antarctica was not always frozen: fossils reveal temperate forests there 50 million years ago, when it was joined to South America and Australia in the ancient supercontinent Gondwana.