Expedition members work at the Shuanghe Karst Caves in Suiyang, Southwest China's Guizhou province. The caves cover a distance of 186.33 kilometers, making them the second longest cave complex in Asia and the longest in China. The measured length increased by 25 kilometers to 186.33 kilometers since researchers from China and France began the expedition into the complex in 1987. (Photo: China News Service/He Junyi)
