Many of Chinese's current modern cities are also thousands of years old. Since canals were a huge part of ancient mass transportation, many cites had an intricate network of them -- at least in southern Jiangsu, at least. Many of these canals were paired with defensive barrier walls. Here in Changzhou, the wall here dates back to the Ming Dynasty. Most of the that wall is now gone, and the last remaining part is in between the Beijing-Hangzhou Grand Canal and a large shopping. Here are some photos.
