This section of Great Wall winds 1.4 miles through lofty mountains and high ridges, many sections of which are made of granite. The unique structure makes the wall almost indestructible. It measures 23 to 26 feet high and four to five yards wide. Both of the wall's inner and outer sides have parapets to defend against enemies coming from the two sides. Some parapets are saw- tooth shaped instead of the regular rectangular form. Below the parapets, there are square embrasures the top of which are designed in an arc structure, different from the traditional round embrasures.