Zhangjiakou Castle is the birthplace of Zhangjiakou urban area. Zhangjiakou Castle was built in Ming Dynasty and has a history of nearly 600 years. It has the reputation of "Wucheng" and is an important military castle on the Great Wall defense line. At the end of Qing Dynasty, Zhangjiakou once became the second largest commercial complex in northern China except Tianjin.