Between 1420 and 1924, 24 emperors of the Ming and Qing dynasties lived here in near-total seclusion, rarely venturing out beyond the 10-metre-thick walls, and commanding an almost divine power over their subjects.

BBC: The perfect trip: China

Stone architecture dating to the Ming and Qing dynasties (which ruled from 1368 to 1912) stands perfectly preserved 40m under Qiandao Lake in Zhejiang province, 400km south of Shanghai.

BBC: China��s Atlantis of the East