Scientists discover deep canyon under Greenland ice
29 August 2013 Last updated at 19:31 BST
A team of scientists has discovered a huge canyon buried deep beneath the mile-thick ice sheet covering Greenland.
Professor Jonathan Bamber, from the University of Bristol, was among the team that used a geological mapping technique to survey the detail and scale of this huge trench in the Earth's surface.
Aerial pictures courtesy of Nasa.