Introduction to Shuanglong Mountain: On the east bank of Longzi Lake, there is a mountain range with two peaks, commonly known as Cao Mountain. It was the place where Cao Cao trained his troops during the Three Kingdoms period, hence the name. The lake at the foot of the mountain is also named after the mountain, and is called "Cao Mountain". lake". Around the time after the Northern Song Dynasty, when the Yellow River took over the Huaihe River, the farmland on both sides of the bank was either flooded or drought. Faced with scorched and withered grain seedlings, people on the lakeside longed for the sweet dew that would come after a long drought. They turned their beautiful wishes into the legend of "Two Dragons Making Rain", and Cao Lake was renamed "Cao Lake" because of this. "Longzi Lake"; the higher mountain in the north is also called "Shuanglong Mountain".