In recent years, Californians have had to deal with some deadly and destructive wildfires. But in fact, this part of the western United States has been shaped by fire for millennia. In this episode of ...

Nearly 10,000 years ago, Earth came out of its most recent ice age. Vast, icy swaths of land around the poles thawed, melting the glaciers that had covered them for nearly 100,000 years. Why, after ...