In the early Ming Dynasty, the Badger continued to intrude the southeast coastal areas of China, burning and killing looting, and doing nothing evil. Zhu Yuanxia Badger "route the sea, solid coast, strict city guard", so the coastal areas began to build flood defense military castles and acropolis. The ancient city of Tongshan on Dongshan Island is one of the few ancient coastal fortifications that have survived the southeast coast of China. It is now well preserved in the Fengdongshi Scenic Area. The long ancient city wall carries the glorious history of Dongshan people's resistance to rejection and protection of the country.