. It is located in Fengjie, Chonqinun Municipality, in the heart of China. This incredible well is completely natural and reaches a depth of 662 meters, is 626 meters long and 537 meters wide. But the most surprising thing is not just its dimensions or almost vertical walls, but the explosion of life it houses.

Xiaozhai Tiankeng is what geologists call a sinkhole or sinkhole, a depression in the land generated, among other factors, by the effect of water. In this case, it was formed over a cave and hosts an underground river that measures 8.5 km and flows into a spectacular waterfall. Its enormous size makes it the largest and deepest sinkhole of its kind, known as Tiankeng, in the world.

In addition to its size, Xiaozhai Tiankeng impresses with the biodiversity it houses inside. Its base is so large that it is home to around 1,300 species of plants, such as ginkgo, and wild animals. Among the most fascinating “tenants” that roam its underground forest, the clouded panther (Neofelis Nebulosa) stands out, a feline with unmistakable fur that measures up to 1.1 meters and normally rests in the trees.

This Tiankeng is located in a wide karst area of ​​280 km2 formed by limestone. Experts believe the sinkhole, between 511 and 662 meters deep, took shape over the last 128,000 years. For much of its history, until the cave's roof collapsed, it was a huge underground cavity. Other Tiankeng of notable size are also located throughout China, such as Dashiwei. Interestingly, despite its size, Xiaozhai Tiankeng began to be studied recently, although the local population has known it since ancient times.