TheGreatWallisnotanisolatedrampart.Itisan integrated military fortification consisted of passes，enemy watch towers，smoke frusta，etc.The building during the past dynasties all followed the rule of“constructing the forts to be dangerous and difficult according to the terrains.”The passes were built either between cloughs and cliffs or at the turn of rivers or at traffic fortresses.In the Ming Dynasty，the fortification system had become extremely rigorous.The wall was built with bricks，with a height of 10 meters and width of 5 meters.There are enemy watch towers every other 30 to 100 meters on the wall.The towers include two kinds，solid and hollow.On solid towers，one can shoot on top only.In hollow towers，soldiers can stay in the underlayers and shoot on top.The watch towers also include rooms for ordinance and forage storage as well as channels for soldier passage.Fortresses in the form of smoke frusta were built on walls on the high mountains.In case war breaks，smoke frustas at the battle front would give alarm and spread rapidly throughout the army.The soldiers run through channels that allow ten persons to pass at the top of the wall，and shoot at the battlement windows.On the traffic main drags along the Great Wall there are passes that were guarded with a large number of forces.For example，in the Ming Dynasty，nine townsof military importance were set up.They are Liaodong Town，Jizhou Town，Xuanfu Town，Datong Town，Taiyuan Town，Yulin Town，Ningxia Town，Guyuan Town，and Gansu Town.These towns guarded the Great Wall to its responsible districts and subsections.Famous passes include Shanhai Guan，Juyong Guan，Jiayu Guan，etc.
Badaling Great Wall is located at Yanqing County at the northwest of Beijing.Its altitude is 1，015 meters and a pass was built on it.There are two gates at the east and west of it.The walls were built by the hills according to the circumstance.The wall is grand and firm with a base of stone bars.The huge brick wall was filled with mud and blocks.The top f loor is spread with square bricks tightly embedded.Juyong Guan Great Wall is located at Changping County.It is a main pass of the Great Wall due to its strategic place.There is a saying that describes its toughness，“one soldier guards the pass and ten thousand soldiers can not get through.”Thus it had been a pass that’s been fought over throughout the dynasties.The height of thewall is averaged at 8.5 meters，the thickness is 6.5 meters，the width of the top is 5.7 meters.It can allow five horses or ten soldiers to pass at the same time.The trees and blossoms are luxuriant on the hills，so the“green of Juyong”had become one of“Beijing’s Eight Sceneries.”Jinshanling Great Wall is located at Luanping County of Hebei Province.Legend says that it was built by Qi Jiguang and Tan Lun who were famous generals against the Japanese pirates.It is approximately 30 kilometers long winding along the hills.The platform of the signal fire is grandly constructed.Passes were installed densely and there are158 fortresses.Shanhai Guan is the east starting point of the Great Wall and it’s located at the northeast of Qinhuangdao of Hebei Province.It is an inevitable pass between Huabei and the northeast of China.In 1381，General Xu Da of the Ming Dynasty built the Great Wall at this spot and established the pass tower.To Guancheng’s north is the green mountains of Yanshan.To its south is the onrushing Bohai Bay.There are four town gates and the stele on the east gate says“Number One Pass in the World.”The west end point of the Great Wall is Jiayu Guan.It is located at the southwest of Jiayu Guan Town on the Gobi desert of Gansu Province.Built in 1372，it’s on a strategic spot and grandly constructed.It’s the first important pass on the Hexi Corridor and an inevitable stop on the Silk Road.
The Great Wall represents the diligentness and wisdom of the Chinese people in the past.Although it has lost its military value for a long time，it nevertheless reflects the dignity，confidence，and independence of the Chinese people.With such spirit and will，the Chinese people can realize a new century of brilliance.