Shanxi Province, 379km (236 miles) W of Beijing, 284km (176 miles) SE of Hohhot, 350km (217 miles) N of Taiyuan
In 398, Datong (then Ping Cheng) became the capital of the Xianbei tribes' first Chinese-style state -- as opposed to a tribal confederation -- under the Northern Wei dynasty. Modeled after the Han Chinese capital of Chang'an (Xi'an), Datong remained their political center for the next hundred years, and it was during this period that most of the Yungang Buddhist Caves were carved out. Four hundred years after the Wei moved their capital south to Luoyang in a step toward Sinicization, the Khitan (or Qidan) established their Liao dynasty (907-1125) capital in Datong. Two buildings from that era survive at Huayan Monastery, which with the Yungang Caves and the spectacular Hanging Temple give ample reasons to visit.
Modern Datong is an industrial center with an abundance of coal that is both a blessing and a curse. Without it, Datong's economy would collapse; with it, skies are rarely clear and lung disease is common. In 2001, the city began implementing pollution-control measures; while some industries have been closed and air quality has certainly improved, don't breathe too deeply in Datong. At the time of writing the city's roads were undergoing a major overhaul, resulting in chaotic traffic, particularly around the railway station. A new city, east of Datong's current center, is also planned, and when complete, many of the government buildings will relocate there.
It's possible to visit Datong as a long day trip from Beijing, but to see all the sights, 2 days are needed.