Remember the 18-mile-long canyon that was discovered by NASA at the Pine Island Glacier in Antarctica? Their researchers just completed the three-dimensional mapping of all its surface with stunning detail, using Digital Mapping System photographs over Airborne Topographic Mapper data.

The crack formed in the ice shelf that extends from one of West Antarctica's fastest-moving glaciers. The path of the crack in this animation stretches roughly 18 miles (30 kilometers) in length (the actual crack is much longer), with an average width of 240 feet (about 80 meters); it was 820 feet (250 meters) at its widest. The canyon ranged from 165 to 190 feet deep (50 to 60 meters), with the floor being roughly at the water line of the Amundsen Sea. Radar measurements suggested the ice shelf is about 1,640 feet (500 meters) feet thick, with only 165 to 190 feet of that floating above water and the rest submerged.

Once it breaks, a new gargantuan iceberg will be released to the ocean. It will be larger than New York City. [NASA Goddard Flickr]