Lukas Furtenbach, a well-known mountain guide, led a British team to climb Mount Everest very quickly, using a special xenon gas treatment. The team left London on May 16th, reached the top on May 21st, and came back home by May 23rd. This xenon gas treatment is meant to help climbers avoid altitude sickness, but it has caused disagreement and is now being looked into by Nepalese climbing authorities. The climbers got ready by training in special tents that simulate high altitude and by having the xenon gas treatment at a clinic in Germany. Furtenbach believes that spending less time on the mountain could reduce harm to the environment, for example, by producing less human waste. He also states that the xenon gas treatment was not used in Nepal, and he says he can show it is safe for climbers.