Switzerland’s Ueli Steck is one of the world’s greatest mountaineers. He is renowned for making record-breaking solo ascents of peaks in the Himalayas and the Alps. But the 36-year-old from Interlaken has never scaled the highest peak on earth—Mount Everest.That’s something he plans to change. He’s about to attempt to climb Everest without oxygen. Reporter Billi Bierling caught up with Ueli Steck in a mess tent at Everest base camp. She began by asking him how important it was for him to get to the top: