Workers celebrate holing-through of Galashan Tunnel in Lhasa, SW China's Tibet

Workers celebrate the holing-through at the construction site of the Galashan Tunnel in Lhasa, southwest China's Tibet Autonomous Region, April 7, 2018. The 4,373-km-long tunnel, about 3,600 meters of altitude, is part of the Lhasa to Nyingchi railway. (Xinhua/Zhang Rufeng)