Yellow-billed choughs fly over the advance camp at an altitude of 6,500 meters on Mount Qomolangma, May 10, 2020. The advance camp sits on a slope next to the end of the East Rongbuk glacier and is the last camp before the snow line and the ice and snow road on Mount Qomolangma. Known as the "devil camp," many of the professional mountain guides, who have reached the peak of Mount Qomolangma countless times, also suffer from altitude sickness here due to its geographical location. It's an area surrounded by mountains and poor air circulation. (Xinhua/Sun Fei)
