Though Nanjing was walled as many as 2500 years ago, the present city wall is basically the work of the first Ming emperor, who extended and strengthened the earlier walls in 1369–73. Built of brick and more than 32km long, construction followed the contours of the country, skirting Xuanwu Lake in the north, fringing Xijin Shan in the east, and tracing the Qinhuai River (which doubled as a moat) to the west and south. The wall was mainly paid for by rich families resettled here by the emperor: one third of it was “donated” by a single native of Wuxiang in Zhejiang province. Its construction employed 200,000 conscripts, who ensured that the bricks were all the same size and specification, each one bearing the names of the workman and overseer. They were held together, to an average height of 12m and a thickness of 7m, by a mortar of lime and glutinous rice paste.
The original structure, of red rock in places, is still plainly visible along a 300m section of the wall at the so-called Shitoucheng, in the west of the city between Caochangmen Dajie and Fenghuang Jie. You can see it from bus #18, which runs outside the walls between Xinjiekou and the west train station.