Ancient Forest Found in Giant Sinkhole

Cave explorers recently came across a sinkhole in South China’s karst region that housed an ancient secret. On May 6, an expedition team rappelled almost 200m down into this deep cave to find not just darkness but a thriving forest. Trees grew as tall as 40m. Undergrowth flourished.

The small amount of sunlight from the entrance was just enough for photosynthesis to do its job. It is likely that this forest is millions of years old. Researchers believe that unknown species of plants and wildlife may thrive here.

The Li River and karst mountains near Guilin, China. Photo: aphotostory/Shutterstock


The limestone geology covers half a million square kilometres and makes up 13% of China. Here, you’ll find natural bridges, deep caves, towers, stone forests, and 30 sinkholes. This newly explored sinkhole, 306m long, 150m wide, and 192m deep, is the largest of them.

Undergrowth at the bottom of the cave. Photo: South China Morning Post/YouTube


Scientists believe that an underground river called Fugui eroded the bedrock within the sinkhole’s three caves. Acid rain from above also helped dissolve the highly soluble rock.

These processes make the region very prone to sinkholes. China has a couple of the world’s largest: the Xiaozhai Tiankeng (511m deep) and the Dragon Hole (300m).

It is likely that ancient forests like this could dwell in other karst landscapes throughout Asia.

Xiaozhai Tiankeng, one of the world’s largest sinkholes. Photo: Brooqi/Wikipedia Commons

Kristine De Abreu

Kristine De Abreu is a writer at ExplorersWeb.

Kristine has been writing about Science, Mysteries and History for 4+ years. Prior to that, Kristine studied at the University of Leicester in the UK.

Based in Port-of-Spain, Kristine is also a literature teacher, avid reader, hiker, occasional photographer, an animal lover and shameless ramen addict.