Xiaozhai Tiankeng sinkhole in China reaches depths of over 660 meters

Xiaozhai Tiankeng, a massive sinkhole located in Fengjie County, Chongqing, China, features a unique two-tier structure within a limestone mountain region. The sinkhole reaches a vertical depth of approximately 666.2 meters, according to official scenic area information, while UNESCO records indicate depths ranging between 511 and 662 meters due to uneven terrain.

The formation consists of an upper elliptical section about 320 meters deep, followed by a nearly vertical section extending another 300 meters below. An underground river flows through the limestone system at the bottom. Accessing the base is a significant physical challenge for visitors, requiring a descent of approximately 2.8 kilometers via more than 2,800 steps, as there are no cable cars or elevators available.