Built for defense purposes, 2000 years ago km long from the east to the west of China, the only man-made object visible from Earth orbit.

Originally built in the periods of the Warring States as a defensive fortification against invaders from the north of China.

It began as independent walls for different states when it was first built, and did not become the "Great" wall until the Qin Dynasty. Emperor Qin Shihuang succeeded to have the walls joined together and extended to 10,000 li to fend off the invasions from the Mongols in the north after the unification of China.

The Great Wall was renovated from time to time after the Qin Dynasty. A major renovation started with the founding of the Ming Dynasty ( ), and took 200 years to complete. The wall we see today is almost exactly the result of this effort.

The Great Wall was built to prevent invasions from the North. Historically, however, both the Mongols (Yuan ) and the Manchurians (Qing ) from the north ruled China. The Great wall did not play a military role. It has attracted thousands of tourists from the world.

The construction of the Great Wall drew heavily on the local resources for construction materials. A great army of manpower, composed of soldiers, prisoners, and local people, built the wall.

The Great Wall starts from Shanhaiguan Pass in the east to Jiayuguan Pass in the west traversing provinces of Liaoning, Hebei, Beijing, Tianjin, Shanxi, Inner Mongolia, Ningxia, Shanxi and Gansu.

Shanhaiguan is a small, sleepy town and port of the northern section of the Bohai gulf, holding the access between northeast China and north China. It is in the Hebei Province. Shanhai Passsituated between the Yanshan Mountains and the Bohai Sea. The No.1 pass of the Great Wall and the key to the defense of two ancient capitals - Beijing in the east and Chang'an (Xi'an) in the west.

The Badaling section of the Great Wall snaking along the mountains northwest of Beijing was built at the beginning of the Ming Dynasty in the 14th century. Being 7.8 metres high and 5.8 metres wide at the top on the average, it has battle forts at important points, including the corners.

Located 10 kilometers south of the Badaling section of the Great Wall and built in an 18.5-kilometre-long valley, the pass has always been an important gateway northwest of Beijing. The name is believed to have its origin in the workers and slaves conscripted to build the Great Wall in ancient times.

The Mutianyu section of the Great Wall is linked to the Gubeikou section on the east and the Badaling section on the west. It is not far from Beijing, and is one of the best sections of the Great Wall.

Located in Miyun County northeast of Beijing, the Jinshanling, like the Simatai division, belongs to the Gubeikou section of the colossal defense barrier. The battlements in the Jinshanling are built along the ridge of a mountain, where the soldiers can resist the invading enemy by taking advantage of the high terrain.

Jiayu Pass is the first pass at the west end of the Great Wall and was built in the Ming Dynasty. It is in the city of Jiayuguan in Gansu Province.The walls on both sides of the pass extend across the desert to join the mountains. It was a strategic passageway on the route to the western regions of China.

The beacon towers on hilltops often played a key role in military communication in ancient war times. Once the enemy pressed towards the border, the signal from the beacon tower would be sent by beacon (fires or lanterns) during the night or by smoke signals in the daytime.

Beautiful legends are centered on the construction of the Great Wall. Among them the most noted is the story about the collapse of a section of the Great Wall caused by Meng Jiangnu's tears, which has been spread widely in folk songs and traditional operas. It is said that 2,000 years ago when Qin Shihuang (the First Emperor of the Qin) was building the Great Wall, a young called Fan Xiliang was forced to work on the construction of the Great Wall, even on his wedding day.

His bride, a girl named Meng Jiangnu, waited at home for her husband for five years but did not hear a word from him. She set off alone to look for Xiliang. After walking all the way on foot, crossing mountains and rivers, Meng Jiangnu finally got to the construction site of the Great Wall, where she was told that her husband had died and was buried under the Great Wall. Hearing this sad news of the death of her beloved, she sat down at the foot of the Great Wall and started crying. She cried day and night, and her wailing made the wall fall.

A famous story is told about Baosi, Queen of the Western Zhou Dynasty (11th century BC BC). She was highly honored, yet she never cracked a smile. King You tried many ways to put a smile on her face, but he failed over and over again. Guo Shifu, a treacherous court official, came and offered advice: "Set the beacon tower on fire and fool your sovereign rulers."

That night, the carriage of the King and Queen reached Lishan Mountain and gave the order. In a split second, the flames of the fire lit up the sky and the sovereign rulers moved their troops to Lishan Mountain. Sure enough, Queen Baosi burst into laughter. Later, King You repeated his joke. In 771 B.C., Quan Rong (a then ethnic group) staged an armed rebellion against the Western Zhou dynasty. King You urgently ordered the beacon tower set on fire, but all the sovereign rulers did not come.