Introduction to Sanlong Crystal Cave: Sanlong Crystal Cave is located between the rocks in the "Sandongshui" ravine in the back mountain of Qingcheng, only 1.5 kilometers away from Tai'an Temple. The cave is a brilliant conglomerate travertine cave formed under extremely special geological conditions 10 to 30 million years ago. There is a river in the cave, which is divided into three floors: upper, middle and lower. In order to allow visitors to view both the cave scenery and the mountain spring, the designer specially laid steel fences as roads on the underground river in the cave. There are magnificent stalagmites, stone curtains and stone flowers in the cave. , under the radiance of colorful lights, reflected in the water, showing the charming colors of the dream world, making people endlessly daydreaming.