Introduction to the ancient city wall: On the right side of the Inspection Office Gate, there is a section of the ancient city wall tightly hugged by the roots of the ancient banyan tree. The remaining wall is 50.7 meters long, 3.7 meters high, and 0.91 meters thick. It is an earth and stone structure. There is also a monument engraved on it. This is the site of the "West Gate of Stone City" built in the 15th year of Shunzhi of the Qing Dynasty (1658 AD). It was once Qi Jiguang's anti-Japanese base and Zheng Chenggong's anti-Qing base. At that time, in addition to the complete city wall, the ancient city of Min'an was surrounded by more than 120 temples, but now only 28 remain. Most of the rest were destroyed in the war, and the ancient city wall was demolished once during the Anti-Japanese War and used for building fortifications.