Datong is the second largest city in Shanxi, and is known by the locals as thecoal capital for a good reason. Datong coal is everywhere: tons of it powering the whole of Shanxi and other cities beyond, piles of it chugging along the roads around town in Soviet style off-blue trucks, smears of it discovered on a face-wiped handkerchief. The city is one of China's most polluted and not only asthma sufferers should think twice before spending any amount of time in the city. Industrial and economic development has bounded in great leaps since the communists came to power in 1950, and huge swathes of the city have been altered into concrete. Despite all this travelers still have a few huge incentives to visit Datong, incentives that are all related to the town's ancient past.