In pics: ancient fortress complexes in north China

A tourist strolls at Dijicheng historical site in Yangcheng County, north China's Shanxi Province, July 7, 2020. Built and developed during Ming Dynasty (1368-1644) and Qing Dynasty (1644-1911), Guoyu ancient city and Dijicheng historical site are typical ancient fortress complexes in north China. (Xinhua/Chai Ting)