On its surface, Greenland doesn’t exactly live up to its name. It’s very cold and covered in a massive ice sheet that’s nearly two miles thick in places. But beneath that sheet there is a giant, rocky island that wasn’t always frozen over, with an undulating topography of valleys and river corridors, including one canyon as deep as the Grand Canyon in places and longer than its famous cousin—spanning the distance from New York to Washington, D.C., twice over. “The Grand Canyon is something you can stand on the edge…
