Yiyuan Rong Cave Group
The Yiyuan Rong Cave Group () is a cluster of Ordovician limestone caves in the area under the administration of the city of Zibo, Shandong Province, China. Rong Cave proper (, ) is the namesake of the cave group. It is located about to the north of the town of Tumen (). The cave group contains more than 40 caves in total and is the largest cluster of limestone caves in China north of the Yangtze River. It covers an area of approximately 10 square kilometers. Other major caves in the group are Thousand-Men Cave (), Resting Cave (), Stone-Dragon  Cave (), Xuanyun Cave (), Nine-Skies Cave (), Coral Cave (), Lingzhi Cave (, after the Lingzhi mushroom), Shenxian Cave (), and Xiaya Cave (, ). The Thousand-Men Cave was used as an arsenal by the Eighth Route Army from September 1938 to March 1939. Some of the major caves in the group have been made accessible to tourists as they are popular attractions.