How the Great Wall of China Works

Famous Landmarks Image Gallery The Great Wall of China was built to keep out invading Huns, and today it attracts 10 million tourists annually. See more pictures of famous landmarks.
TEH ENG KOON/AFP/Getty Images

­Long b­efore tanks and long-range missiles­ became available for combat, militaries relied on less technologically advanced mechanisms to protect themselves against invaders. The Great Wall of China was designed to perform the most basic defensive war principle: Keep the good guys in and the bad guys out.

While China's was not the first wall built to serve this purpose (Denmark, Korea and the Roman Empire all built walls prior), the Great Wall is arguably one of the world's most famous and impressive man-made structures. The name "Great Wall of China" is largely a term bestowed upon the structure by Westerners. In fact, it has traditionally been known to the Chinese as the Wan Li Chang Cheng, which translates to "Ten Thousand Li Long Wall," or "Long Wall of Ten Thousand Li" (li is a Chinese unit of length, with two li being equivalent to one kilometer).

­So how great is the wall? Its reported length is widely disputed and ranges anywhere from a paltry 1,500 miles (2,414 kilometers) to 4,163 miles (6,700 kilometers) [source: Power, National Geographic]. To settle the debate once and for all, researchers began in 2007 what they believe will be a four-year trek to survey the dimensions and route of the wall. This may seem unnecessarily complex, but considering the intense and treacherous topography the Great Wall crosses over -- including steep mountains, desert, grasslands and more -- it's easy to see why this is no simple feat. The study, which is being conducted by the State Administration of Cultural Heritage and the State Bureau of Surveying and Mapping, will record the wall's length from east to west (from the Gobi Desert to the Yellow Sea), since the wall was built to protect against invaders from the north. And it's not only the length of the wall that's up for debate: It's also difficult to pinpoint how many cities and provinces are included in the Great Wall's layout. One Chinese tourism bureau states that the wall winds its way across nine cities and provinces: Beijing, Gansu, Hebel, Inner Mongolia, Liaoning, Ningxia, Shaanxi, Shanxi and Tianjin [source: Travel China Guide].

In this article, we'll learn the history behind the Great Wall, whether or not it served its purpose well and how it eventually became obsolete. We'll also take a look at the current state of the structure and how it's being protected after years of abuse by both Mother Nature and humans alike. But first, who built the wall?

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The Rise of the Great Wall

This engraving of the Great Wall of China shows some of the treacherous terrain that the barrier winds across.
This engraving of the Great Wall of China shows some of the treacherous terrain that the barrier winds across.
Mansell/Mansell/Time & Life Pictures/Getty Images

When the first portions of what would eventually become the Great Wall were built, they weren't part of a large master plan to block off China from the north. Instead, beginning anywhere from the seventh century B.C. to the fifth century B.C. (the start date is disputed by archaeologists), many small walls were erected by the six different states that would eventually become China as we know it. The point of the walls was to provide protection from the often warring states as well as a variety of invaders, including the Huns.

In 220 B.C., the Qin Dynasty unified the Qin state with the six other warring states (Han, Wei, Chu, Yan, Zhao and Qi, in that order). The emperor Qin Shihuang then ordered the separate pieces of the Great Wall in the northern states to be connected. He did this to provide maximum security from the troublesome Huns. Thus, the Great Wall began to take shape in its most infantile form.

Construction on the wall, which is made out of several different materials including bricks, stone, grass, rock and earth, continued over subsequent centuries and was completed by Chinese soldiers, criminals and commoners. This imposing structure didn't come without a price, however. It's estimated that thousands upon thousands of Chinese workers died building the Great Wall, and many of them were buried inside the structure itself.

In addition to the Qin Dynasty, other dynasties were involved in the Great Wall's long and complex construction history.

  • The Western Han Dynasty, which ruled from 206 B.C. to A.D. 24, restored the Qin Wall and ordered multiple extensions of the wall, including three sections of the Hexi Great Wall.
  • The Northern Wei Dynasty (386-534) continued the wall's expansion, adding more than 620 miles (997 kilometers) to the structure.
  • Despite being short on time, the Northern Qi Dynasty (550-577), added the Wall of Northern Qi, which covered hundreds of miles in many different countries and provinces.
  • The Sui Dynasty (581-608), Liao Dynasty (916-1125) and the Jin Dynasty (265-420) all continued the tradition, adding thousands of miles among them to the wall's length.

Under the Ming Dynasty, the wall underwent its biggest transformation. Next, we'll look at the reinforcements this dynasty added.

The Great Wall under the Ming Dynasty

Tourists at Simatai climb a portion of the wall built during the Ming Dynasty. This section of the wall was built as one of four major strategic strongholds for defensive purposes.
Tourists at Simatai climb a portion of the wall built during the Ming Dynasty. This section of the wall was built as one of four major strategic strongholds for defensive purposes.
TEH ENG KOON/AFP/Getty Images

It wasn't until the rise of the Ming Dynasty in 1368 that the Great Wall of China as we know it today was brought to fruition. The Ming Dynasty had to contend with a great number of attacks by minority tribes, so it made substantial additions to the wall.

The complexity and sheer size of the Ming wall outdid all of its predecessors. Not only did the dynasty add length, it also added double and triple walls in some places to reinforce previously built structures and confuse attackers. In fact, in many places the wall is wide enough on top for someone to drive a car on it, averaging an impressive 22 feet (6.7 meters). Although the wall sports an impressive girth, it's not visible from outer space as the old myth claims. If that were true, major highways would also be visible -- many are much larger than the Great Wall.

The Ming Dynasty also increased the military prowess around the wall. Fortresses were placed intermittently along the length of the wall to store military supplies, and beacons were built to provide much-needed light. Another innovation to the wall that the Ming Dynasty introduced was guards. Guard towers were erected at strategic points along the wall from which guards would send out smoke signals and fire cannons to notify each other of possible hostile attacks. The only major downfall to these guard towers is that they were manned by humans, who sometimes fell prey to enemies' bribes and allowed them access to the other side of the wall.

Construction on the Great Wall was an ongoing and successful effort under the Ming Dynasty until the 17th century when China could no longer thwart the efforts of the Manchu, invaders from Manchuria who successfully infiltrated China. This takeover, which brought down the Ming Dynasty and gave rise to the Qing Dynasty, effectively halted the Great Wall's development, which spanned more than a whopping 2,000 years.

In the next section, we'll take a look at how the wall fell into disrepair.

The Great Wall's Downward Spiral

Graffiti stains this archway of the Great Wall of China, despite the nearby sign that forbids desecration of the wall.
Graffiti stains this archway of the Great Wall of China, despite the nearby sign that forbids desecration of the wall.
FREDERIC J. BROWN/AFP/Getty Images

The Great Wall isn't just one of the world's most famous landmarks, it's also the only historical monument marked on world maps by cartographers. Understandably, the Great Wall is a magnet for tourism. In fact, more than 10 million people visit it each year [source: BBC News]. While its status as a bona fide tourist attraction results in valuable revenue, tourism and other factors have taken a massive toll on the wall's structural and aesthetic integrity.

First, it's important to note that the Great Wall hasn't exactly been in top-notch condition for some time. Following the Manchu invasion in the 1700s, it was largely abandoned as a military priority. After all, why would the Manchu waste time and energy on something that failed to keep them out? As a result, the wall became overgrown by vegetation and began to deteriorate as a result of earthquakes and exposure to snow, wind and rain. Battles ranging from tiffs with the Huns to high power assaults with Japan in the 1930s and '40s also hastened the wall's decline.

Even local residents' everyday activities have contributed substantially to the Great Wall of China's corrosion. Herding animals and gathering firewood have sped up the deterioration process after years of abuse -- stomping livestock and human tools have chipped away at its edifice. What's more, Mao Zedong holds some responsibility for the damage: He encouraged the Chinese people to use bricks and other parts of the wall to build homes and other structures as recently as the 1950s. Road construction crews have even dared to knock holes in portions of the wall to build highways.

Ironically, the tourism industry is one of the largest contributing factors to the wall's demise. For years, tourists have taken pieces and bricks from the wall as souvenirs. They've etched names and epithets into the wall, and vendors have set up shop with souvenir stores, cable cars, parking lots, fast food restaurants and more within feet of the landmark. Unsightly advertisements, signs and public utilities have shown up in high-traffic areas along the wall, and litter and graffiti have marred it and surrounding areas. Well-meaning tourists and locals have taken it upon themselves to restore portions of the wall in unauthentic and unreliable ways. As a result of all of these factors, a whopping 50 percent of the Great Wall has disappeared entirely, with a remaining 30 percent in ruins and a mere 20 percent classified as being in "reasonable" condition [source: Mooney].

Next, we'll learn about some initiatives to restore the Great Wall.

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Revitalizing the Great Wall

Organizations have taken on the responsibility of preserving the wall, but it's not yet out of the danger zone. It will take time before everyone recognizes the national importance of this landmark.
Organizations have taken on the responsibility of preserving the wall, but it's not yet out of the danger zone. It will take time before everyone recognizes the national importance of this landmark.
Tom Stoddart/Getty Images

Until recently, the Chinese government was reticent to discourage or limit tourist access to the Great Wall for fear that it would decrease revenue to the area. However, as it has become increasingly clear that the wall is in peril, the government, with input from organizations such as the International Friends of the Great Wall and the Great Wall Society of China, has put laws and regulations in place to stop damage to and properly restore the structure. In fact, the World Monuments Fund added the Great Wall to its list of the World's 100 Most Endangered Sites.

In 2003, the Beijing Administrative Bureau of Cultural Relics enacted regulations to protect the Beijing portion of the wall, which shoulders some five to six million tourists each year [source: People's Daily Online]. The regulation allows the organization the authority to prohibit the construction of any building within 1,640 feet (500 meters) of the wall that can cause either unpleasant aesthetic damage or physical desecration. Seemingly innocent activities that have an adverse effect on the wall have been declared taboo. These activities include pitching a tent, gathering firewood, herding animals and setting up stands to charge admission to less savvy tourists.

Soon after the Beijing regulations were put in place, the Chinese government enacted the first national law aimed at protecting the Great Wall. The government officially prohibited activities like removing bricks or stones from the wall, holding raves or parties on top of it, carving words into the wall or building a home too close to it. Raves and driving and carving on the wall have become such big problems in recent years that in 2006, the government instituted fines of up to $62,500 for institutions and $6,250 for individual violators. In addition to enacting laws designed to protect the Great Wall from further damage, the Chinese government has also allocated funds to allow for continued preservation and restoration of the monument. Advocates encourage individuals to contribute to these efforts in several ways, such as by planting trees, removing litter and making sure to never take anything from the wall or leave anything behind.

Thanks to these efforts, awareness about the Great Wall's status as a historical landmark of intrinsic value and beauty to China and the world has become more established, effectively beginning to turn the tide of centuries of neglect and abuse. Unfortunately, in many of the less metropolitan areas where the wall is located, locals don't understand the cultural significance of the structure. In fact, they continue to routinely use bricks for building purposes. Several men in Inner Mongolia were even accused for removing what they deemed to be a pile of earth from a particularly ancient portion of the wall to use as a landfill. Simply put, many people who are just trying to survive aren't as concerned with a landmark as they are with taking care of their families.

Although it may continue to be an uphill battle for some time, the Great Wall's preservation has been embraced as a matter of the utmost cultural and historical importance, especially because it serves as a gateway into China's storied and colorful history.

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