Greenland's Grand Canyon
September 2, 2013 – A team of scientists accidentally discovered an enormous canyon under the ice sheet of Greenland that is more than one-and-a-half times longer than the Grand Canyon!
The discovery was made by scientists working with NASA's Operation IceBridge with colleagues Italy and Canada. They used ice-penetrating radar and airborne data to piece together what the land that lies beneath the ice looks like.
The canyon 750 kilometres long (465 miles), 800 metres (2,624 feet) deep, and is hidden under two kilometres (1.3 miles) of ice.
It was probably created by a north-flowing ancient river until 3.5 million years ago when global temperatures cooled and Greenland became covered in ice. It probably still plays a role in draining melting ice water out to sea.
We easily can see almost every inch of Earth's land now, thanks to Google Street View, but we still know very little about what lies beneath the ice that covers our north and south poles.
"It's remarkable to find something like this when many people believe the surface of the Earth is so well mapped," said the study's lead author Jonathan Bamber of England's University of Bristol.