Arctic Dinosaurs (Oct. 2008)

Experts in Alaska investigate how dinosaurs managed to thrive in polar regions. Watch now (50 mins.)

The Big Energy Gamble (Jan. 2009)

Can California's ambitious plan to cut greenhouse gases actually succeed? Watch now (50 mins.)

Dinosaur Plague (July 2009)

Insects caught in amber spark a controversial theory about what killed the dinosaurs. Watch now (15 mins.)

Extreme Ice (Mar. 2009)

An acclaimed photographer teams up with scientists to document the runaway melting of arctic glaciers. Watch now (50 mins.)

Megabeasts' Sudden Death (Mar. 2009)

Scientists propose a radical new idea of what killed off mammoths and other large animals at the end of the Ice Age. Watch now (50 mins.)

Mt. St. Helens: Back From the Dead (May. 2010)

Thirty years after the massive eruption, could it happen again? Watch now (50 mins.)

Profile: Lonnie Thompson (July 2009)

A climatologist struggles to save ancient history preserved in ice that is now melting. Watch now (15 mins.)

Secrets in the Salt (July 2009)

Salt deposits that formed 250 million years ago hold tantalizing hints of early life. Watch now (15 mins.)

Storm That Drowned a City (Nov. 2005)

Experts and eyewitnesses reconstruct the devastating floods that Hurricane Katrina unleashed on New Orleans. Watch now (49 mins.)