Limestone and dolomite cover about 130 km2 which takes up about 1 / 7 areas of the national land in china . besides , it is pluviose , muggy and damp in there areas , all of these accelerate the karst caves . there are more than 100 , 000 caves and holes under the earth , which consists of a karst caves kingdom in the world 中国石灰岩和白云岩的出露面积约为130km2 ，约占全国总面积的1 7 ，加之雨量充沛，气候温热潮湿，喀斯特较为发育，地下洞穴孔道，计有数十万个之多，成为世界上的洞穴王国。
