An American climber died today on his way to the summit of Mount Everest. The 50-year-old mountaineer died close to the Balcony, a small platform above the 8,000-metre mark considered the mountain's death zone. Murari Krishna Sharma of Everest Parivar Expedition told AFP, it is the third death so far this climbing season. <br/><br/>The death zone is notorious for its difficult terrain and thin air, where low levels of oxygen heighten the risk of altitude sickness.<br/><br/>Legendary Swiss climber Ueli Steck died late April while on an acclimatisation climb, and 85-year-old Min Bahadur Sherchan perished attempting to reclaim his title as the world's oldest person to summit Everest.