The Yiyuan Rong Cave Group (Chinese: 沂源溶洞群; pinyin: Yíyuán Róng Dòng Qún) is a cluster ofOrdovician limestone caves in the area under the administration of the city of Zibo, Shandong Province, China. Rong Cave proper (Chinese: 沂源溶洞; pinyin: Yíyuán Róng Dòng, 36°16′06″N 118°04′14″E / 36.268428°N 118.070669°E) is the namesake of the cave group. It is located about 13 kilometres (8.1 mi) to the north of the town of Tumen (Chinese: 土门镇; pinyin: Tŭmén Zhèn). 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 (Chinese: 千人洞; pinyin: Qiānrén Dòng),Resting Cave (Chinese: 养神洞; pinyin: Yǎngshén Dòng), Stone-