Introduction to the ancient military fortress ruins: The ancient military fortress ruins are located in Nanjinguan of Xialao River, adjacent to the mouth of the gorge in the east and the river in the south. According to the "Geography of the North Country", this area was called "Xialaoxu" or "Xialao Pass" in the Han Dynasty. ". The site was discovered during the construction of the riverside promenade in 1983. The ancient military fortress was more than ten meters long from north to south, nine meters wide from east to west, and three meters high. It was built with geometric patterns and cord patterns, and was collected layer by layer, resembling an inverted tower. fight.