A staff member of China Railway Guangzhou Engineering Group (CRECGZ) works in the Ban Nakok Tunnel in northern Laos' Oudomxay Province, on May 28, 2020. China Railway Guangzhou Engineering Group (CRECGZ) drilled through the Ban Nakok Tunnel, the second longest tunnel along the China-Laos railway, on Sunday. (CRECGZ/Handout via Xinhua)