Constructors work inside the Silk Road International Convention Center in Dunhuang in Northwest China's Gansu province on August 3, 2016. Two main venues of the Silk Road (Dunhuang) International Cultural Expo, Dunhuang Silk Road International Convention Center and Dunhuang Grand Theater, have been almost completed. The expo will be held in Dunhuang on Sept. 20. [Photo/Xinhua]