Xiaozhai Tiankeng: The Deepest Sinkhole on Earth

Shariq Ali
Valueversity

Located in China’s Chongqing province, Xiaozhai Tiankeng—also known as the “Heavenly Pit”—is the largest and deepest natural sinkhole in the world.

This astonishing geological formation is 662 meters deep and 537 meters wide. It was formed over a period of approximately 128,000 years due to the collapse of underground limestone caves.

What makes this sinkhole truly unique is its internal structure, consisting of two parallel layers. Within it flows an 8.5-kilometer-long underground river that cascades down as a magnificent 46-meter-high waterfall. During the rainy season, the river swells dramatically, adding even more beauty to the scene.

Xiaozhai Tiankeng is not just a geological wonder but also a biological treasure. It has its own unique microclimate, supporting over 1,285 species of plants and animals. Among these are the rare clouded leopard, flying squirrels, and the Chinese giant salamander. Some plants discovered here were once thought to be extinct.

Since the first formal scientific expedition in 1994, a 2,800-step staircase has been built, allowing visitors to descend into this natural marvel. It is not just a pit—it’s a living museum of nature, biodiversity, and evolutionary history.