There are typically only a few days per year with the right conditions to summit Mount Everest.<br />Business Insider reports many parts of the mountain only allow one person to climb at a time, creating a bottleneck.<br />The death of at least two climbers has been blamed on large crowds that have left people queuing in the mountain's "death zone."<br />The death zone is an area more than 26,000 feet above sea level where oxygen is so limited that the body's cells start to die. <br />
