China - arguably the longest continuous civilization - while known for its plethora of art and culture, still has yet a lot of unknown history to be unearthed. 

One of the legendary historical sites is the Hanging Temple (悬空寺) in the Chinese City Datong - a 1,500-year-old architectural wonder hanging on a sheer precipice.  Little do people know that the Hanging Temple is just the tip of the iceberg - deep underneath Datong lies the city of temples dedicated to Buddhism, Toaism and Confucianism. An underground city, once the most advanced and most worshipped center of Datong, had been gradually covered and detached from the outside world due to frequent catastrophic landslides in the past century.

The city of temples was completely shut off after the 1976 Tangshan Earthquake (唐山大地震), and has since been reclaimed by nature. It is believed that only ones with the most innocents minds - free from turmoil and resentment - would be invited into the hidden underground city of temples, and to be able to catch a glimpse of Buddhist's "Pure Land".