The Que'ershan Tunnel, stretching 12.997 kilometers on National Highway No 317, in Ganzi, Sichuan province, opens to traffic on Sept 26, 2017. It is said to be the world's highest tunnel on a highway. The tunnel, whose highest point is 4,378 meters above sea level, was completed 15 years after the launch of the project. With the opening of the tunnel, it takes only 10 minutes to pass through the perilous and steep Que'ershan Mountain that stands 6,168 meters above the sea level. The project is projected to become a new impetus to help drive the economic and social development of the remote Tibetan region. [Photo/VCG]

The Que'ershan Tunnel, stretching 12.997 kilometers on National Highway No 317, in Ganzi, Sichuan province, opens to traffic on Sept 26, 2017, some 15 years after the project started. [Photo/VCG]

Buses enter the Que'ershan Tunnel on National Highway No 317 in Ganzi, Sichuan province, on Sept 26, 2017. [Photo/CHINA DAILY]