Visitors go to Datong because of the Yungang Caves, 6 mi/10 km west of the city—it's about an eight-hour train ride west of Beijing. The caves contain a fine collection of carved-sandstone Buddhist figures (more than 50,000 of them in 53 caves, though many have been defaced or beheaded). In general, this collection is not as impressive as that in the Mogao Caves near Dunhuang—but they are easier to get to, and you are not hurried through the caves as much.
Datong itself is a filthy coal-mining town with a few good sites. These include the impressive Nine Dragon Screen (a 150-ft/50-m tiled wall made of glazed ceramics depicting a fire-breathing dragon) and the 12th-century Huayan Monastery.
155 mi/250 km west of Beijing.