Longyou Grottoes are located in a riverside hill 3 kilometers north of Longyou County. Locals call this mountain "Tongtan Mountain", but the mountain's abdomen actually contains 24 artificial caves of different sizes and exquisite layout. It is said that Longyou Grottoes were first dug in the West Han Dynasty Xuandi "bian county all built warehouses", its function is to reserve grain, goods and war supplies, and experienced the generation, especially when the Sui Dynasty called "North Changping warehouse"