The Great Wall was built over 2,000 years ago, by the emperor of Qin Dynasty (221 B.C - 206 B.C.) Qin Shi Huang, the first emperor of China.

After conquered and united China from seven Warring States, the emperor connected and extended four old fortification walls along the north of China that originated about 700 B.C. with the purpose of defensing against the invading nomadic Hsiung Nu tribes north of China (the Huns) and other warrior tribes from the north. The advantages of the enormous barrier diminished with the advancement of gunpowder and other weaponry.

But this wall was not constructed as a Qin’s single endeavor, it was rather created by the joining of several regional walls built by the Warring States. It was located much further north than the current Great Wall, and very little remains of it.

The Great Wall that can still be seen today actually was built during the Ming Dynasty, on a much larger scale and with longstanding and steady materials, all the bricks were produced in kilns that set up along the wall. The slaves carried the bricks on their backs and also transported by donkeys, mules and even goats had a brick tied to their head before being driven up a mountain. And meanwhile those workers were under the attacks of the bandits and some Huns, so many people died while building the wall, therefore it has dubbed as "longest cemetery on Earth" or "the long graveyard". Their bodies were not entombed in the wall for the body buried in the wall would have weakened its structure, thus the bodies were buried nearby instead.

The Ming Dynasty Great Wall starts on the eastern end at Shanhai Pass, near Qinhuangdao, in Hebei Province, next to Bohai Gulf. Spanning nine provinces and 100 counties, the final 500 kilometers have all but turned to rubble, and today it ends on the western end at the historic site of Jiayu Pass, located in northwest Gansu Province at the limit of the Gobi Desert and the oasis of the Silk Road. Jiayu Pass was intended to greet travelers along the Silk Road. Even though The Great Wall ends at Jiayu Pass, there are many watchtowers extending beyond Jiayu Pass along the Silk Road. These towers communicated by signal fire from which the Wall provided early warning of an attack.

There were once some doubtful points about whether the Great Wall was visible or not. Richard Halliburton's 1938 book Second Book of Marvels said The Great Wall is the only man-made object visible from the moon. This myth has persisted, assuming urban legend status, and even entering school textbooks. Yet astronaut William Pogue thought he had seen it from Skylab but discovered he was actually looking at the Grand Canal near Beijing. He spotted the Great Wall with binoculars, said that "it wasn't visible to the unaided eye." An Apollo astronaut said no human structures were visible at a distance of a few thousand miles. Yang Liwei a Chinese astronaut said he couldn't see it at all. The Great Wall is only a few meters wide-sized resemble to highways and airport runways and is about the same color as the soil surrounding it. Veteran U.S. astronaut Gene Cernan has stated: "At Earth orbit of 160 km to 320 km high, the Great Wall of China is, indeed, visible to the naked eye." Ed Lu, Expedition 7 Science Officer aboard the International Space Station, adds that, "It's less visible than a lot of other objects. And you have to know where to look."

A recent photograph taken from the International Space Station confirms that China's Great Wall can be seen with the naked eye after all. Leroy Chiao, a Chinese-American astronaut, took what the state-run China Daily newspaper says is the first photographic evidence that the Great Wall could be seen from space with the naked eye, under certain favorable viewing conditions and if one knows exactly where to look.

The Great Wall is on the lists of the "Seven Medieval Wonders of the World" was made a UNESCO World Heritage Site in 1987.