History

The Chinese were already familiar with the techniques of wall-building by the time of the Spring and Autumn Period, which began around 8th century BC. During the Warring States Period from 5th century BC to 221 BC, the states of Qi, Yan and Zhao all constructed extensive fortifications to defend their own borders. Built to withstand the attack of small arms such as swords and spears, these walls were mostly made by stamping earth and gravel between board frames.

Qin Shi Huang conquered all opposing states and unified China in 221 BC, establishing the Qin Dynasty. Intending to impose centralized rule and prevent the resurgence of feudal lords, he ordered the destruction of the wall sections that divided his empire along the former state borders. To protect the empire against intrusions by the Xiongnu people from the north, he ordered the building of a new wall that connects the remaining fortifications along the empire"s new northern frontier. Transporting the large quantity of materials required for construction was difficult, so builders always tried to use local resources. Stones from the mountains were used over mountain ranges, while rammed earth was used for construction in the plains. There are no surviving historical records indicating the exact length and course of the Qin Dynasty walls. Most of the ancient walls have eroded away over the centuries, and very few sections remain today. The Han, Sui, Northern and Jin dynasties later in history have all repaired, rebuilt, or expanded sections of the Great Wall at great cost to defend themselves against invaders from the north.

The Great Wall concept was revived again during the Ming Dynasty, following the Ming army"s defeat by the Mongols in the Battle of Tumu in 1449. The Ming had failed to gain a clear upper-hand over the Mongols after successive battles, and the long-drawn conflict was taking a toll on the empire. The Ming adopted a new strategy to keep the Mongols out, by constructing walls along the northern border of China. Acknowledging the Mongol control established in the Ordos Desert, the wall followed the desert"s southern edge instead of incorporating the bend of the Huang He.

Unlike the earlier Qin fortifications, the Ming construction was stronger and more elaborate due to the use of bricks and stone instead of rammed earth. As Mongol raids continued periodically over the years, the Ming devoted considerable resources to repair and reinforce the walls. The sections near the Ming capital of Beijing were especially strengthened.

Towards the end of the Ming Dynasty, the Great Wall helped defend the empire against the Manchu invasions that began around 1600. Under the military command of Yuan Chonghuan, the Ming army held off the Manchus at the heavily fortified Shanhai Pass, thus preventing the Manchus from entering the Liaodong Peninsula and the Chinese heartland. The Manchus were finally able to cross the Great Wall in 1644, when the gates of Shanhai Pass were opened by Wu Sangui, a rebel Ming border general. The Manchus quickly seized the Ming capital of Beijing, and subsequently defeated the remaining Ming resistance to establish the Qing Dynasty.

Construction and repairs of the Great Wall were discontinued under the Qing rule, as China"s borders extended beyond the walls and Mongolia was annexed into the empire

 

 

 

Notable areas

The following three sections are located in Beijing Province where reconstruction has taken place and which are regularily visited by modern tourists:

• The “North Pass” of Juyongguan pass, known as the Badaling. When used by the Chinese to protect their land, this wall was well-manned by guards so as to guard China’s capital, Beijing. Made out of stone and bricks from the hills, this portion of the Great Wall is 7.8 meters high and 5 meters wide.

• One of the most striking sights of the Ming Great Wall, is where the wall climbs extremely steep slopes. It runs 11 kilometers long, ranges from 5 to 8 meters in height, and 6 meters across the bottom, narrowing up to 5 meters across the top. Wangjinglou is one of Jinshanling"s 67 watchtowers, rising 980 meters above sea level.

• South East of Jinshanling, is the Mutianyu Great Wall which winds along lofty, cragged mountains from the southeast to the northwest for approximately 2.25 kilometers (about 1.3 miles). It is connected with Juyongguan Pass to the west and Gubeikou to the east.

Another notable section lies near the eastern extremity of the wall where the first pass of the Great Wall was located on the Shanhaiguan (known as the “Number One Pass Under Heaven”), the first mountain the Great Wall climbs. Jia Shan, is also located here, as is the Jiumenkou, which is the only portion of the wall that was built as a bridge. Shanhaiguan Great Wall is referred to as the “Museum of the Construction of the Great Wall”, because of a temple, the Meng Jiang-Nu Temple, built during the Song Dynasty.

 

Visibility from the moon

Ripley"s Believe It or Not! cartoon from May 1932 makes the claim that the wall is "the mightiest work of man, the only one that would be visible to the human eye from the moon" and Richard Halliburton"s 1938 book Second Book of Marvels makes a similar claim. This belief has persisted, assuming urban legend status, sometimes even entering school textbooks. Arthur Waldron, author of the most authoritative history of the Great Wall, has speculated that the belief might go back to the fascination with the "canals" once believed to exist on Mars. (The logic was simple: If people on Earth can see the Martians" canals, the Martians might be able to see the Great Wall.)

The Great Wall is a maximum 30 feet wide and is about the same color as the soil surrounding it. Based on the optics of resolving power (distance versus the width of the iris: a few millimetres for the human eye, metres for large telescopes) an object of reasonable contrast to its surroundings some four thousand miles in diameter (such as the Australian land mass) would be visible to the unaided eye from the moon (average distance from earth 238,857 miles). But the Great Wall is of course not a disc but more like a thread, and a thread a foot long would not be visible from a hundred yards away, even though a human head is. Not surprisingly, no lunar astronaut has ever claimed he could see the Great Wall from the moon.