<p><br> Spelunkers rappel 300 feet (90 meters) into the Greenland ice sheet. Glacier caves such as these form when seasonal meltwater or geothermal vents cut fissures and channels through an ice sheet. Because they are made of ice, glacier caves can be quite unstable and present unique challenges to spelunkers.</p>

Glacier Caving


Spelunkers rappel 300 feet (90 meters) into the Greenland ice sheet. Glacier caves such as these form when seasonal meltwater or geothermal vents cut fissures and channels through an ice sheet. Because they are made of ice, glacier caves can be quite unstable and present unique challenges to spelunkers.

Photograph by Carsten Peter

Caves

See cave photos from National Geographic.

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