The Crescent Spring and Singing Sand Dune scenic area is seen in Dunhuang, Northwest China's Gansu province, Sept 9, 2016. As an important stop on the ancient Silk Road, Dunhuang is known for the Mogao caves and Yumen Pass. This year, the Silk Road (Dunhuang) International Culture Expo will be held from Sept 20 to Oct 10. [Photo/Xinhua]