Staff members patrol the Wang'erxi Bridge, a stone arch railway bridge along the Chengdu-Chongqing Railway, June 13, 2019. Connecting Chengdu of southwest China's Sichuan Province and Chongqing Municipality, the 505-km Chengdu-Chongqing railway is the first railway line contructed after the founding of the People's Republic of China. It was designed by China and built with domestic materials. The construction of the railway kicked off in June 1950, and the whole project was finished in two years, with more than 100,000 soldiers and civilians working in tough environment. The railway has been making remarkable contribution to regional economic development since it began operation on July 1, 1952. (Xinhua/Liu Chan)