The Jinshanling Great Wall is a complicated and well preserved fortification systems and possesses the largest number of watchtowers. These watchtowers were made by huge bricks, 5-8 miles high, and each one built in a different architectural style. The distance between each tower is about 50 to100 miles away. Some of them are half-timbered, some are stone, some with one eave, some with two-eave. The roofs of the towers are many and varied, flat,arched, quadrangular or octagonal. It is an exemplary section of the Great Wall and hence comes the saying that the Jinshanling section is the most essential part of the 10,000-li (6,700 kilometres) Great Wall.