Introduction to historical sites: Qinwang Lake is where King Qin Li Shimin fought against Liu Heita's rebel army in the late Sui Dynasty and early Tang Dynasty. The Tang army and the rebel army fought here for three days and three nights, and blood flowed into the river. In order to commemorate the fallen soldiers, Li Shimin ordered General Yuchi Jingde to build Qiquan Temple to comfort the heroes.