Introduction to Yin Yangtan Weng Valley: On both sides of the canyon here are many large and small stone niches scattered on the red cliffs that are tens to more than a hundred meters high. The cause is that the bottom of the cliff was eroded by water flow, forming a series of stone niches with small tops and large bellies. Then, the uplift of the earth's crust moved the stone niches to the middle of the cliff. This is a rare geological phenomenon. spectacle.