Staff members celebrate the drill-through of the Yanjiazhai tunnel of the Guiyang-Nanning high-speed railway in Dushan County, southwest China's Guizhou Province, June 14, 2021. The 1.67-km-long tunnel was drilled through on Monday, enabling further construction work for the Guiyang-Nanning high-speed railway, which will run with a design speed of 350 km per hour. (Xinhua/Liu Xu)