You mean the cinstructure? Ming Great Walls were made up of walls, pass towers, fortress, terraces on the wall and frustas, beacon towers, etc. Except for the wall in Ji County which was make of stone and brick, others were usually made based on rammed earth walls, only with pass gate tower and fortress wrapped with brick. The fortification built in Ming, according to date from State Administration of Cultural Heritage and State Bureau of Surveying and Mapping, is about 8852km long. Manmade walls are 6260 km long. There were partly moat,natural barriers and reformed natural barriers.