Introduction to Yinkeng Cave: Yinkeng Cave is a stone cave located on the cliff on the right side outside Huxuetan. The mouth is 3 meters high and unfathomably deep. It is said that this cave was dug by silver miners in the Song Dynasty. There are still stone millstones, treadmills, pounding mortars and silver-washing troughs nearby. In 1983, an old man from Hunan caught 15 monkeys in this cave.