An immense canyon previously unknown for all of human history has been discovered under a mile of Greenland ice, NASA announced Thursday.
NASA's Operation IceBridge, an airborne research project that studies polar ice, discovered the continuous bedrock canyon with data collected between 2009 and 2012. The canyon extends 460 miles from central to northern Greenland, making it longer than Arizona's Grand Canyon, and reaches depths up to 2,600 feet, similar to portions of the Grand Canyon.
NASA believes the canyon predates the ice sheet that has covered Greenland for several million years.
"One might assume that the landscape of the Earth has been fully explored and mapped," said Jonathan Bamber, professor of physical geography at the University of Bristol in the United Kingdom, and lead author of the findings published Thursday. "Our research shows there's still a lot left to discover."