China's longest karst caverns stretch for 186.333 km(12/12)

Expedition members work at the Shuanghe Karst Caves in Suiyang, Southwest China's Guizhou province on October 31, 2016. The Karst Caves, measured at 186.333 kilometers, is the second longest complex of caverns in Asia. (Photo: China News Service/He Junyi)