Today marks the 5th anniversary of the biggest climbing disaster ever on Mount Everest. Eight climbers died when they were caught in a sudden storm on the worlds highest mountain. American David Breashears was there in 1996, and helped to lead the rescue that kept the death toll from climbing. Last month, he journeyed back to Everest on a pilgrimage. In part one of our latest Radio Expedition from NPR and the National Geographic Society, we hear recordings Breashears made on his journey.