Meet Ina Vandebroek, a salsa-dancing ethnobotanist who boldly ventures into far-off cultures.

Scientists propose a radical new idea of what killed off mammoths and other large animals at the end of the Ice Age.

An acclaimed photographer teams up with scientists to document the runaway melting of arctic glaciers.

Examine the high-tech eavesdropping carried out by the National Security Agency and the pitfalls of surveillance in an age of terrorism.