GREAT NATURE -- Into the Unknown: Greenland's Ice Caves

The Arctic: Greenland. Recent global warming is causing unprecedented changes in this frozen land. The frequency of glacier collapse is rapidly increasing, and in some cases, the speed of glacial motion has doubled in the past 15 years. To understand these changes, the crew teams up with a French glaciologist and travels to the massive Greenland ice sheet. This episode introduces the frozen landscape and explores the deep mysterious ice caves that suck in meltwater.