Introduction to Tongshan Ancient City: Tongshan Ancient City is 158 kilometers away from Zhangzhou City and located in Tongling Town, northeast of Dongshan Island. In the 20th year of Hongwu's reign in the Ming Dynasty, in order to defend against Japanese invaders, Zhou Dexing, the Marquis of Jiangxia, built a stone fort here and set up a water fortress to defend the coast. Qi Jiguang, a famous anti-Japanese general in the Ming Dynasty, and Zheng Chenggong, a national hero, both camped here to train navy troops.