Xiaozhai Tiankeng

In the limestone uplands of Fengjie County, in the far east of Chongqing, the earth drops away into what is considered the deepest sinkhole in the world. Xiaozhai Tiankeng — "heavenly pit" in Chinese — is roughly 626 metres long and 537 metres wide, and between about 511 and 662 metres deep depending on where the rim is measured. Its volume is put at around 119 million cubic metres: space enough to swallow a small mountain.

The pit is not a simple funnel but two bowls set one inside the other. The upper one falls about 320 metres to a sloping terrace; below it a narrower shaft drops a further 342 metres to the floor. That floor is the work of water: an underground river, some 8.5 kilometres long, runs through caves beneath the pit, and the collapse of the rock above it over a long span of time opened the hole to the sky. Inside, the river plunges over a waterfall about 46 metres high. The cave system was explored in 1994 by the China Caves Project.

Isolated from the plateau above, the depths hold their own forest. More than 1,200 plant species have been recorded here, along with rare animals such as the clouded leopard and the Chinese giant salamander. A stone staircase of about 2,800 steps winds down the walls, so that visitors can descend through the layers of cliff, terrace and green floor and feel the scale from inside — a hike down that is as much part of the experience as the view from the rim. The wider karst landscape around it also includes the long Difeng fissure, a deep crack in the plateau nearby.

Getting there

Xiaozhai Tiankeng lies in Xiaozhai village, Xinglong town, about 90 km by road from the county seat of Fengjie. The nearest airport by distance is Enshi Xujiaping (ENH), about 48 km away across the provincial border in Hubei. Fengjie has a high-speed rail station; from there buses or taxis continue to Xinglong town and the tiankeng.