Greenland is covered with a sheet of ice, but that hasn't stopped scientists from examining the land beneath. A recent study led by geographer Jonathan Bamber mapped an enormous valley in the interior of the island:
The broad chasm is up to 2,600 feet (800 meters) deep and 6 miles (10 km) wide, similar to America's Grand Canyon in scale, the researchers said. The distinctive V-shaped walls and flat bottom suggests water carved the buried valley, not ice, Bamber said. Though it is not the world's deepest canyon, it's the longest, handily besting the 308-mile-long (496 km) Yarlung Tsangpo Grand Canyon in China.