Tun-Huang was a city in Cathay, near the Gobi Desert. The city was famous for its large array of temples. Nearby were the Cave of the Thousand Buddhas and the Cave of Five Hundred Eyes.

In 1289, the First Doctor, Susan, Barbara Wright, and Ian Chesterton visited the city whilst travelling from Lop to Peking with Marco Polo, (TV: "Five Hundred Eyes") before they moved on east to Su-Chow. (TV: "The Wall of Lies")