The underground Milky Way in Mengyin is a typical karst landscape, also known as karst cave. Located 6 kilometers northwest of Mengyin County, Linyi City, Shandong Province, Youzhuang Village is located. In the cave, the fog is shrouded, the temperature is constant all the year round, and the river is gentle and deep, entering the cave. In the middle of summer, it is refreshing and pleasant, while in the middle of winter, it is warm as spring. [2]