Introduction to the afterimage of the cave door: The afterimage of the cave door is also called "Longkou Rock" and "Qiyun Cave" by the locals. According to legend, two immortals, Lu Sheng and Hou Sheng, came to Yunshan to refine elixirs before they became immortals and lived here. At the end of the Ming Dynasty, the ruins still existed. At that time, there was a man named Pan Yingxing who had served as a high official in the imperial court in Wugang. When he saw these ruins, he impromptuly wrote "The Shadow of the Cave Gate" and regarded it as the Ten Scenery of Yunshan. It was settled.