Many people try to climb up Mt. Everest, but Lewis Gordon Pugh saw a niche in the market and has become the first to swim under it. The endurance swimmer is the only person to successfully swim across the 1km glacial lake next to the Khumbu Glacier. From the article: "He came close to drowning during test swims for the event amid bouts of altitude sickness on the Pumori Lake, which sits 17,000 feet above sea level. But an adapted approach saw him through to complete the swim in a time of 22 minutes and 51 seconds."