Six Mi-17 helicopters fly over the Gobi desert in the Kunlun Mountains. A PLA army aviation brigade stationed in Xinjiang organized its troops to conduct realistic flight training on such subjects as performing emergency operations, attacking armored troops, providing close range fire support, conducting in-depth air-landed operations and so forth in the Kunlun Mountains, southwestern Xinjiang Uygur Autonomous Region, China, on March 2, 2016.(Photo/www.81.cn)