Dunhuang, Gansu

Basically 1.3 million sq km of desert, Dunhuang harks back to ancient China with its camels, sand dunes, starry skies and zero pollution. It served as a defensive bulwark during the Han Dynasty (206BC-220) and a major stop on the ancient Silk Road. Walls of the Mogao Caves, a system of Buddhist cave temples near the town, feature religious art dating from the 4th to 14th centuries. There are about 600 surviving cave temples, of which 30 are open to the public.