Introduction to the city wall ruins: Dinghai Castle has experienced more than 600 years of wind and frost, nearly a hundred times of war and looting, and countless wind disasters. Especially in the 37th year of Jiajing, the main city gate was breached and fell, and the whole city was devastated. The buildings in the city were destroyed. In the early years of the Republic of China, the city tower was demolished, and then Dinghai Castle was occupied by the Japanese army three times. In the early days of the founding of the People's Republic of China, Dinghai Castle was often bombarded by artillery fire from Taiwan's Matsu defenders. But the biggest misfortune of the ancient city came from the Cultural Revolution in the 1960s and 1970s. The stone strips of the city wall were pried to build houses, resulting in the destruction of several hundred feet of the city wall. Today, only the ruins of the restored city wall are less than 100 meters long.