About Great Wall of China:The great wall averages 7.8 meters in height and is 6.5 meters wide at the base and 5.7 meters at the top. The width is enough for five horses to go side by side.On both sides of the road there are dwarf walls called "parapet wall". The 1.7-meter-high "crenel wall" is the outer wall. On its top, there are battlements for patrolling and watching. Below the battlements are peepholes, used for firing at the enemy. At intervals along the inner wall are arched entrances with stone stairways leading to the top of the wall.

Every other 300 to 500 meters, there are fortresses. There are two kinds of fortresses. One is two-storied fortress called fighting tower. The ground floor was used for living, storing weapons and the top floor was used for watching and shooting. Another kind is fighting terrace or enemy terrace, which was used for patrolling and fighting.

History of Great Wall:The Great Wall has a history of more than 2,000 years. As early as the Warring States Period, in order to self-protect, rival kingdoms built walls around their territories. This is the earliest Great Wall.When Qin Shihuang, the first emperor in Chinese history, unified the whole country in 221B.C, he ordered to build another new wall on the base of the original walls of the Countries Qin, Zhao, and Yan in effort to guard against the invasion of the northern nomadic tribes.