Introduction to Laolongtan: Laolongtan, commonly known as "Jinghe Nao", is located at the east foot of the main vein of Liupan Mountain, where the Jinghe River flows out, and is known as a natural water tower on the Loess Plateau. Laolongtan is not only famous for its crystal clear water and the confluence of hundreds of springs, but also for its majestic and dangerous charm and wonderful and magical legends. According to legend, this is the place where Wei Zhengmeng killed the old dragon of Jinghe River.