Guan Yiquan, a Chinese scholar in Lanzhou, the capital of Gansu, also became convinced that Liqian had links to Rome.

ECONOMIST: So it's said, anyway

And in one of the most controversial stories we came across this week, a Chinese developer is proposing to flatten 700 mountains in the Lanzhou area in order to build a new city.

ENGADGET: Inhabitat's Week in Green: invisibility cloak, a Hobbit House and a portable washing machine

The story begins in 1992, when an army unit from Lanzhou in neighbouring Gansu province, drilling with state permission, made a decent oil find in Jingbian county.

ECONOMIST: In rural China, a private oil boom became a state-owned one

Lanzhou in north-west Gansu ranked last, while Haikou on southern Hainan island was rated with the cleanest air.

BBC: China media: Analysing North Korea