Xiaozhai Tiankeng is the deepest and largest natural pit on the planet. Located in Fengjie, Chonqinun County, in the heart of China. This incredible pit is completely natural and reaches a depth of 662 meters, length of 626 meters, and width of 537 meters. But the most astonishing thing is not just its size or its almost vertical walls, but the explosion of life it hosts.
Xiaozhai Tiankeng is what geologists refer to as a pit or sinkhole, a depression in the ground formed, among other things, by the effect of water. In this case, it formed over a cave and houses an underground river that measures a total of 8.5 kilometers and flows into a spectacular waterfall. Its large dimensions make it the largest and deepest pit of its kind in the world, known as a tiankeng.
In addition to its size, Xiaozhai Tiankeng impresses with the biodiversity it hosts inside. Its base is so large that it houses around 1,300 species of plants such as ginkgo and wild animals. Among the most fascinating “tenants” that roam in their underground forest, the clouded leopard (Neofelis nebulosa) stands out, a feline with unmistakable fur that reaches 1.1 meters and often rests on trees.
This tiankeng is located in a vast karst area of 280 km2 formed by limestone. Experts believe that the pit, with a depth between 511 and 662 meters, took shape in the last 128,000 years. For much of its history, until the roof of the cave collapsed, it was a huge underground cavity.
China is also home to other significantly sized tiankengs, such as Dashiwei. Strangely, despite its size, Xiaozhai Tiankeng has only been studied relatively recently, although the local population has known about it since ancient times.
