(210517) -- NYINGCHI, May 17, 2021 (Xinhua) -- Photo taken on Aug. 18, 2020 shows the Doxong Pass and tunnel exit on the highway linking Pad Township in the city of Nyingchi and Medog County, southwest China's Tibet Autonomous Region. Construction of a highway passing through the Yarlung Zangbo Grand Canyon, known as the world's deepest canyon with a maximum depth of 6,009 meters, was completed on Saturday in southwest China's Tibet Autonomous Region. The project took almost seven years to complete. A 2,114-meter tunnel was dug through on Saturday morning, marking the completion of the major construction of the 67.22-km road connecting Pad Township in the city of Nyingchi and Medog County. (Photo by Dong Zhixiong/Xinhua)