Workers celebrate the breakthrough of the second tunnel of the China-Laos railway in Laos' northern town of Muangxay, Oudomxay Province, on June 12, 2018. The China Railway Guangzhou Engineering Group (CREC Guangzhou) has broken through the Ban Naven Tunnel of the China-Laos railway, securing steady progress in the construction of the railway project. (Xinhua/Liang Wendong)