Going back to the 14th century this historic landmark is a symbol of Nanjing’s time as the capital of the Ming Dynasty between 1368 and 1421. Founder of the Ming Dynasty Emperor Zhu Yuanzhang ordered its building to protect Nanjing from invaders. Purple Mountain, Xuanwu Lake and Qinhuai River provided additional natural defences as the Wall snaked around them. The curved Wall was unusual, as up until then city walls had been built in straight lines. Completed in 1386, Nanjing is one of the few cities to retain its original walls. Making the state-protected Ming Great Wall a national treasure. The Ming Great Wall was 35 kilometres long. It was considered to be one of the longest city walls in the world. Today about 25 kilometres are still intact with the following six sections being opened to the public: Zhonghua Men (Treasure Gate) to Shen Ce Men Gate (Peace Gate). It is approximately 6 kilometres long. Zhong Shan Gate (Zhong Shan Men) to Guanghua East Street (Guang Hua Dong Jie), it is approximately 2 kilometres. East Water Gate (Dong Shui Guan) to West Water Gate (Xi Shui Guan), it is approximately 6 kilometres. Qing Ling Mountain (Qing Ling Shan) to Defense Garden (Guo Fang Yuan), it is approximately 1 kilometre. Ding Huai Gate (Ding Huai Men) to Lion Mountain (Shi Zi Shan), it is approximately 4 kilometres. Zhong Fu Road (Zhong Fu Lu) to Zhong Yang Gate (Zhong Yang Men), it is approximately 2 kilometres. http://www.cityofnanjing.com/article/the-ming-great-wall-of-nanjing/