10 sites around the globe in trouble, and how you can tread lightly.
» Endangered Planet
Gallery: 10 Endangered Sites
Canadian polar bears, the Tower of London, the Outer Banks: Global warming is affecting them all. We zero in on 10 danger zones.
Video: Touring Greenland's Icy Waters
Scenes from a boat ride past icebergs broken from the Ilulissat Icefjord in the waters surrounding the town of Ilulissat, Greenland.
Video: Viking Ruins
The Viking ruins scattered over southern Greenland embrace both religion and mystery.