Bill Kurtis takes a close look at the mighty grizzly bear with researchers at Yellowstone National Park. Then, learn more about dolphin intelligence and the fascinating way in which they communicate.

Laurie and Dan Krause moved to South Africa to try to protect the African cheetah.

Bill Kurtis takes you deep inside the African Maasailands and through the Ngorongoro Crater to search for a mysterious warrior artifact that Maasai tribesmen use to maintain their traditions.

Bill Kurtis tells the story of scientists who are trying to save the Rio Paraguay, the second largest river in South America. They fear that a plan to turn the river into a giant shipping highway could harm the environment.

Host Bill Kurtis joins five members of Conservation International's Rapid Assessment Team in Bolivia as they work with local scientists.

Sail through the caves of Greece to examine the endangered monk seals.

Walter McCrone demonstrates how he uses a simple light microscope to solve many scientific mysteries. And, computers, lasers, DNA fingerprints, psychological profiles--they're all tools of crime profiler John Douglas, who has assisted the FBI.

Ornithologist John Fitzpatrick documents the discovery of a new species of bird.