The Yadan National Geological Park is seen in Dunhuang, northwest China's Gansu Province, Sept. 8, 2016. As an important stop on the ancient Silk Road, Dunhuang is known for the Mogao caves, Yumen Pass, etc. This year, the Silk Road (Dunhuang) International Culture Expo will be held from Sept. 20 to Oct. 10. (Photo/Xinhua)
