About the size of Rhode Island, the iceberg known as A23a got stuck in an ocean vortex this summer, spinning in place for months. Now, it's free, and heading back into open Antarctic waters.
A fossil of an armadillo-like mammal appears to bear cut marks from butchering by humans, suggesting people were living in South America at least 20,000 years ago, even earlier than once thought.
On mountaintop glaciers of Alaska, Washington and Oregon, billions of tiny black worms are tunneling upward to the barren, icy surface. What lures them, and how do they survive the frozen depths?
