A one-hour walking circuit loops you past limestone caves, primeval vegetation and an underground river in this sinkhole that reaches 312m in height. Trek to the sinkhole's bottom via an ethereal-looking cavern with a hole in its roof: around noon, a shaft of light shines through the hole to illuminate the cavern floor, reminiscent of Raiders of the Lost Ark.
There's no bus to Chuandong Sinkhole, but if you go to Dashiwei Sinkhole, the staff can sometimes arrange a driver to take you there and back to the city centre for ¥80 to ¥100 a car (seats four). The only other way is to take the bus from Leye (¥7) to the junction, from where you'll have to walk 3.8km.