View from a small window in the wall of the vast Niubizi Tian Keng in the Er Wang Dong cave system. Cave explorers wander around the heavily vegetated floor. (Robbie Shone/Caters News Agency)
Gaining height step by step, Hong Meigui member Duncan Collis climbs a thin rope up to a small ledge overlooking the vast floor surface of Niubizi Tian Keng in the Er Wang Dong cave system. (Robbie Shone/Caters News Agency)
American speleologist Erin Lynch peers down over her shoulder into a giant void of cloud. The floor is over 787 feet deep. (Robbie Shone/Caters News Agency)
Suspended on a thin rope, engulfed in cloud, a tiny figure is dwarfed by the sheer size on a monumental scale of Cloud Ladder Hall. The beam of light cast by a head torch pierces the fog yet illuminates nothing. This naturally formed room is so large it has its own weather system going. (Robbie Shone/Caters News Agency)
Spectacular beddings in the roof of Quankou. (Robbie Shone/Caters News Agency)
Duncan Collis and Erin Lynch walk through a section of cave in San Wang Dong called The Sea of Tranquility. (Robbie Shone/Caters News Agency)
Erin Lynch drills another hole to continue her traverse above the white water and descending waterfall into the blackness beyond. (Robbie Shone/Caters News Agency)
A lonesome cave explorer ascends a rope out from the Niubizi Tian Keng. (Robbie Shone/Caters News Agency)
Large stalagmites at the foot of a giant ascending ramp to another level of development in San Wang Dong create a spectacle mid way through a section of cave called Crusty Duvets. (Robbie Shone/Caters News Agency)
Calmer waters crystal clear pools and slow moving streams make it easier to explore Quankou Dongs main river passage. (Robbie Shone/Caters News Agency)
Duncan Collis and Erin Lynch walk through a section of cave in San Wang Dong called The Sea of Tranquility. (Robbie Shone/Caters News Agency)
The Highlanders 