Yang Zhi gets ready for a cave dive. Photos provided to China Daily

Members of Yang's team share a common interest in exploring the unknown world.

They are dark and deep. So, what attracts caving enthusiasts to risk their lives and explore these caverns? Xu Wei discovers more in Chongqing.

Yang Zhi loves the unknown. That's why he is hooked on cave exploration, as a trip into a cave as deep as several hundred meters is filled with uncertainties.

As the captain of a cave exploration team in Chongqing municipality, the 37-year-old and his team have led people to more than 400 caves in Chongqing and its neighboring Sichuan and Guizhou provinces.

"The best part about a cave expedition is going into places no one has ever been before," says Yang. "You know neither your exact destination nor what you are going to see."

The vast distribution of karst topography characterized by caves in Chongqing, Guizhou, Yunnan provinces and the Guangxi Zhuang autonomous region, has provided a rich source for cave explorers.