Photo taken on July 23, 2020 shows a panoramic view of a branch base of China Railway No. 8 Engineering Group (CREC-8), a Chinese engineering company engaged in the construction of the China-Laos Railway in northern Laos' mountains. The China-Laos Railway will run more than 400 km from Boten border gate in northern Laos, bordering China, to Vientiane with an operating speed of 160 km per hour. The project started in Dec. 2016 and is scheduled to be completed and open to traffic in December 2021. (Photo by Pan Longzhu/Xinhua)

Aerial photo taken on July 17, 2020 shows the China-Laos Railway's Luang Prabang Mekong River Super Major Bridge in Laos. (Photo by Mei Zhengyou/Xinhua)

Photo taken on July 28, 2020 shows the construction site of the China-Laos Railway in northern Laos. (Photo by Pan Longzhu/Xinhua)

Photo taken on May 31, 2020 shows the construction site of the China-Laos Railway in northern Laos. (Photo by Pan Longzhu/Xinhua)

Aerial photo taken on July 24, 2020 shows the China-Laos Railway's Ban Ladhan Mekong River Super Major Bridge in Laos. (Photo by Pan Longzhu/Xinhua)

Photo taken on May 31, 2020 shows the construction site of the China-Laos Railway in northern Laos. (Photo by Pan Longzhu/Xinhua)

Photo taken on June 4, 2020 shows the construction site of the China-Laos Railway in northern Laos. (Photo by Pan Longzhu/Xinhua)

Photo taken on May 29, 2020 shows the construction site of the China-Laos Railway in northern Laos. (Photo by Pan Longzhu/Xinhua)

Photo taken on July 29, 2020 shows the construction site of the China-Laos Railway in northern Laos. (Photo by Pan Longzhu/Xinhua)

Aerial photo taken on July 15, 2020 shows the China-Laos Railway's Ban Ladhan Mekong River Super Major Bridge in Laos. (Photo by Mei Zhengyou/Xinhua)