Arctic Ascent with Alex Honnold

Alex Honnold leads a six-week expedition to Eastern Greenland to make a first ascent of one of the highest unclimbed rock faces in the world. But this is much more than a climbing trip. With the help of glaciologist Heidi Sevestre, Alex and the team investigate the impact of climate change on the glaciers, ice caps and fjords in this remote part of the Arctic. (National Geographic)