A staff member of China Railway No. 5 Engineering Group stands at the entrance to Nathong No. 2 Tunnel of China-Laos Railway after the tunnel was dug through in Oudomxay Province of Laos, some 400 km north of Lao capital Vientiane, April 15, 2019. Two tunnels of the China-Laos Railway, namely Nathong No. 2 and Nateuy No. 2, were dug through on the same day on Monday by the constructor China Railway No. 5 Engineering Group. (Xinhua/Hu Yong)