Over 2,000 years old, the Great Wall of China remains one of the great wonders of the world, an engineering feat rarely matched in the 22 centuries since its construction began. Stretching 4,500 miles, from the mountains of Korea to the Gobi Desert, it was first built to protect an ancient Chinese empire from marauding tribes from the north. But it evolved into something far greater, a boon to trade and prosperity and ultimately a symbol of Chinese ingenuity and will.

The Great Wall is actually a series of walls built and rebuilt by different dynasties over 1,000 years. And while they often served the same purpose, these walls reflected the worlds, both natural and cultural, in which they were erected. The Great Wall is an emblem of China's evolution.

The project began under the tyranny of Qin Shihuangdi in the Qin Dynasty, in 221BC. Older, ruined walls were already there, but were broken into separate pieces here and there in Northern China. With both forced and conscripted labor, the old walls were restored and a new, continuous wall created. The goal was a 3,000-mile-long fortification meant to protect China's northern frontiers against attack by marauding nomads. Much of the forced labor came from exiled scholars and philosophers, most of them died there. This made the Qin Emperor extremely unpopular.

With the fall of the Qin Dynasty, the wall fell into centuries of neglect. China's northern frontiers were at the mercy of fierce outsiders known as the Xiongnu. After 70 years of war, the Xiongnu were crushed once and for all. With this victory by Han Wu-Di, the greatest of the Han Dynasty emperors, came a westward expansion into the wilderness of Central Asia. To protect that border Wu-Di began China's second great campaign of wall building. His engineers restored the crumbling Qin wall and extended it 300 more miles across the forbidding Gobi Desert. With Central Asia under Han control, safe caravan routes - the legendary Silk Roads - were established, opening China to the commerce and culture of the Western world. Traders from Rome, Antioch, Baghdad and Alexandria trekked eastward to deal in jade, gold, spices, horses, precious gems and of course, silk.

The Han also added beacon towers to the Wall, spaced 15 to 30 miles apart. Columns of smoke were used to warn defenders of an attack. One smoke column meant an outpost was being threatened by a force of fewer than 500 troops, two columns meant an attacking force of fewer than 3,000.

The greatest of all wall builders were the ones in the Ming Dynasty, whose astounding accomplishments dwarfed what had been done earlier by the Qin and the Han. The Ming not only built more wall than any other dynasty, but theirs was also bigger, longer, more ornate and more imposing. Coming out of the Mongol occupation (Yuan Dynasty), the Chinese were eager to protect themselves from further attack from the Northern tribes.

The Ming wall was built of a tamped earth interior encased in a facing of kiln-fired brick, pushing wall-building technologies to the limit. The Ming wall snakes acrobatically across some of China's most forbidding terrain, rising in places at an angle of 70 degrees. Such dramatic engineering wouldn't have been possible without the Ming's advanced brick-making technology. At a time when European builders were still relying upon cumbersome cut stone, the Ming were using state-of-the-art kilns to mass produce bricks, which were as strong as modern-day masonry blocks.

In recent years, the Great Wall has been slowly chipped away by people who need stones to build houses. As useless as the Great Wall is now in modern times, it is still a symbol of pride in China. Today, old, crumbling sections of wall are allowed to be dismantled, while the newer walls, built in the Ming Dynasty, are kept in condition, because it is a national relic, as well as bringing in plenty of (of course) tourist money.

It is a widely held belief that the Great Wall Of China is the only man-made object visible from outer space, or at least one of two or three, depending on the claims of the Louisiana Superdome and Jebel Ali. But despite it being printed on the back of a Trivial Pursuit card, it's simply not true. The wall is thousands of miles long, but it's only about twenty feet wide, and not particularly contiguous.

While the Gemini V spacecraft was in space, astronauts Gordon Cooper and Charles Conrad made note of a number of visible objects, including a checkerboard pattern that had been laid out in Texas and the aircraft carrier that they were going to land on. Since the longest of aircraft carriers is just over 1100 feet, it stands to reason that a huge number of other objects would have been visible had Cooper and Conrad been on a sightseeing tour rather than a NASA mission. But perhaps they weren't far enough away.

The first problem comes in defining exactly where outer space is. Is it one hundred miles up? One thousand miles up? Halfway to the Moon? On the Moon itself? At the altitude the Space Shuttle orbits (typically between 190 and 350 miles above sea level), the Great Wall is a thin, barely visible line. But other objects are visible as well, such as the Golden Gate Bridge, the Panama Canal, and the Fresh Kills Landfill on Staten Island. The Eisenhower interstates are also faintly visible as well, as well as crisscrossing patches of farmland adjacent to the Great Wall itself.

What about the Moon? There are only a few eyewitness accounts, but none have reported seeing it. To the contrary, they've all clearly stated that it's not visible. Moonwalkers Neil Armstrong and James Irwin stated that it was not visible, and photos from the Apollo missions prove it as well. The continents themselves are hard to make out from the surface of the moon. A wall twenty feet wide doesn't have a prayer.

Aside from eyewitness accounts, one can calculate the possibility of seeing an object from the moon simply by knowing the distance between the Earth and the moon and the resolution of the human eye. With 20/20 vision, an object would need to be almost a half a mile in two dimensions for it to be visible from that far away. The entire Earth fits in less than two degrees of arc when viewed from the lunar surface. Not much room for distinguishing features.

So what's the last man-made thing you can see as you travel away from the Earth? Well, assuming it's not self-illuminating, like any number of cities whose light is visible at night, the objects that would be the last to be obscured would be the Dutch polders.

Drop me off a Chinese wall.
Peel my fingers off the rim.

We trusted our hired driver, who piloted his car north from the blind smoggy blankness of Beijing. The car was, like us, a western import and our driver spoke enough english to act as something of a tour guide. North of Beijing, however, there simply isn't much to point out. The very fact of a Chinese highway is interesting enough in itself to pass the ride.

There were rough roadside analogs to things you might see driving through the rural US. Filling stations constructed mostly out of crumbling cinderblock and spanish tile; gas pumps sprouting from dirt. Snack stands hawking white dumplings which steamed in the January air. Yes, kids leading oxen. This is suburban Beijing.

Further north, into the hills, the road is dirt and the people more sparse. Regardless, this is tourist country even if it is the off-season and the locals watch our passing car intently from deep inside their tented coats. More cinderblock shelters, handpainted. Cars on blocks in the front yard are an international language.

Up and around through the twists, we can see the Wall looming on the mountain ridge. Our driver parks us in a paved oval at the base of the mountain. The parking lot is clearly large enough to accomodate several tour busses and a fleet of autos, but we are the only people there. The Wall is a long way up a steep mountainside, but the only strenuous climbing involved is walking the rough path up to the ski lift. The vendors we pass are starved for customers, and call after us in vague english as we puff our way up the incline.

They fire up the chair lift just for us. No line, no waiting. Simply pile into the orange gondola. My father is afraid of heights, and sits stiffly as our glass-bottomed carton swings out of the station and up, bobbling on a thin wire of braided steel. He's been working in China for over a year and, sadly, knows a bit about the general state of maintenance for things mechanical. I, in my giddy ignorance of potential plummeting death, snap photos of our ascent.

We pour out of the lift at the summit and there, out the back of the station, are simply stairs up onto the wall. And there we are. We are walking on the Great Wall of China. Alone. Ancient stone under new snow under my (probably) Chinese-labor-made boots. Bitter winter wind tears at us, but my counterfeit North Face jacket prevents total hypothermia. We crunch off, along the snake, seeing what we can see.

I run my hands along the rough rock, creating a tactile memory of where I've been and what I'm doing. It's my habit around historical construction, or famous geology. Bits of my skin are left behind, and I take fragments of the attraction with me. I peer through the loopholes, imagining marauding Mongols pouring up the mountainside. The truth about this thing is that the whole mountain is the Great Wall. Imagine a plundering army roaring down from the north; not only must they struggle up an entire mountain, then they must overcome a giant wall and soldiers stationed thereon. Assuming they're successful, and assuming they don't die in later raids, they're forced to cart whatever booty they can grab back over the accursed thing. The Great Wall of China, at its essence, is psychological warfare.

My dad decides to strike out ahead, nearer to where the Wall crumbles away, to explore. I capture a photo of him, tiny and colorful, on the crest of a hill out on the wandering line. My stepmother stands in a guard house, silhouetted against what small amount of daylight filters in through the tiny door. We slip and slide our way up, down, along stairs, and back to where we started.

There is one other man on the wall; spiritual descendent of the Qing guardsmen. He sits at a folding card table, selling souvenirs. We are the only people he's seen all day, but he remains professionally cool as we pick through his pins and postcards. I buy a pin to prove to the rest of the world where I've been, and a postcard for a girl back home. "Yeah, baby... I've been to the Wall". My parents haggle in their limited Chinese and, not for the first or last time, I feel like a mute moron.

Back to the chair lift and, of course, it's out of service. My father heads out to a promentory to try to get reception for his cellphone, the better to tell his office he's either going to be late or completely stranded. About an hour of locked bathrooms and unmanned, locked refrigerators later the winch starts up again, and we're off floating down the mountainside. The Wall has barely noticed our visit.

Off the wall and down the path, we are set upon by rabid t-shirt vendors. They bar our path and will not let us through without looking at their goods. I bought a t-shirt with mysterious Chinese characters on it which almost certainly translate to "gullible American tourist". It cost about a dollar.

Our driver had passed the time playing dominoes with the underworked trinket vendors. He smiled as we stamped down the path and went to start the car. "How was it?" he asked us, his long, white teeth visible from gum to blade. We enthused appropriately in the substance-light way you converse with those unfamiliar with your language.

We roared off back to Beijing, and there was so much to see along the way that I fell asleep.

With regard to the above node by Orange Julius (that the Great Wall isn't particularly discernible from space), there is additional information as to the visibility of the Great Wall from space.

An American astronaut, Gene Cernan, told the Straits Times (a reputable daily newspaper; THE newspaper in Singapore) that he saw the Great Wall from outer space with his own eyes. He was giving an interview in Singapore, when he attended the Asian Aerospace 2004, a biannual airshow.

Eugene A. Cernan served aboard Gemini IX (June 3-6, 1966), Apollo 10 (May 18-26, 1969) and Apollo 17 (December 6-19, 1972). During his first space mission, he became the second American to walk in space. He was also slated in backup positions for Gemini 12, Apollo 7 and Apollo 14. Having spent a precise 556 hours and 15 minutes in space, out of which more than 73 hours was spent on the Moon, he is uniquely qualified to speak on this subject.

His exact quote was: 'At Earth orbit of 160km to 320km high, the Great Wall of China is indeed visible to the naked eye.' He also confirmed that it was not observable from the moon; however, only continents and oceans are perceivable across that distance.

The skill involved with sighting the Great Wall, apparently, lies in knowing where to look and eyeballing it hard enough. From this we can deduce that the Great Wall is not easily noticeable from space. Depending on your knowledge of geography, your perseverance, how good your eyesight is and the weather conditions, you might (or might not) be able to see the Great Wall.

Therefore, when other space cadets such as the newbie Chinese astronaut Colonel Yang Liwei said that the thin, undulating structure could not be viewed from space, he probably lacked one or more of the factors listed above. (I stand corrected: I found out that he orbited at about 350 kilometers from Earth; perhaps he was too far away to be able to see the Wall.)

Although the notion that the Great Wall was easily discernible in space was blasted as an urban legend, NASA's position that it could not be perceived due to its narrow width and its earth-like colouration also needs revision.

Incidentally, the fact that the Great Wall is perceptible from outer space is about to be struck from Chinese textbooks in mainland China because of Col. Yang's report.


The Straits Times Interactive - http://straitstimes.asia1.com.sg/
You can view the Straits Times article "You can see the Great Wall from space" online at http://straitstimes.asia1.com.sg/news/story/0,4386,240173,00.html? from 14th March 2004 to 17th March 2004, only, after which it will be archived and inaccessible except for a fee.

Biographical Data of Eugene A. Cernan - http://www.jsc.nasa.gov/Bios/htmlbios/cernan-ea.html

Orbit details of Chinese manned space mission: "Report: Manned space mission to orbit earth 14 times" - http://www1.chinadaily.com.cn/en/doc/2003-10/09/content_270451.htm

An Associated Press report: "China to Correct Great-Wall-In-Space Myth" - http://www.newsday.com/news/nationworld/world/wire/sns-ap-china-great-wall-myth,0,6755225.story?coll=sns-ap-world-headlines

The Great Wall of China wasn't just designed to keep the barbarians out. It was also designed to keep the non-barbarians in. Here's why.

For much of human history across Asia and Africa, political rulers have faced a problem that is nearly unimaginable in today's densely-populated world. The basic problem was that their subjects kept running away. When our primitive ancestors first settled down to form static farming communities, productive land was much more abundant than people to farm it. Land where one could make a living through means other than farming was even more abundant. The rulers of nascent states who wanted to support luxuries for themselves and their courts - along with armies and priesthoods - as well as building public facilities like roads and irrigation systems for rice had to extract the surplus production from a population of farmers.

This meant that the most elementary task for a pre-modern ruler in many parts of the world was the acquisition and retention of manpower. We hence find that the power of such individuals was often defined not by how much land they controlled, but how many people were answerable to them. Slavery flourished in many parts of the world for much of human history, as those captured in wars were forced to return to the homeland of the capturing state to provide manpower. The population of slaves in many Thai, Burmese and Indochinese states was equal to or exceeded the number of normal citizens. Normal citizens, meanwhile, would often choose to run away from the centres of state power if demands for taxation, forced labour or military recruitment became too onerous.

This brings us back to the Great Wall of China. For most of the time that the various walls in northern China were being constructed or actively maintained - basically before the Qing dynasty took power in 1644 - one of their main purposes wasn't just to allow for military defence from northern barbarians, but also to control the migration of Chinese to the vast open spaces to the north where they could start a new life on plentiful land, outside of the demands of rapacious elites south of the Great Wall. Imagine the pre-modern world as a blank canvass with a series of ink blots strewn around; where the ink spreads is state power, and the blank canvass between are areas free of the demands that states place on people they control. Epidemics, wars, rebellions, or high taxes could all be enough to encourage people to flee the ink which, unlike today, covered nothing like all of the canvass.

The Ming dynasty, which ruled China before the Qing, conducted frequent censuses of the population and taxable resources of the areas it controlled, staking a claim to the wealth and labour of the hundreds of millions of Chinese people in its territory. The lure of the ungoverned northern frontier - and of the southwestern frontier, which Chinese rulers never tried to control so systematically - was obvious. Thence lay productive land outside of the state's control. Previous dynasties had provided less stability, but the periodic disorders, rebellions and civil wars that wracked Chinese territory prior to the Ming were another reason to flee.

Far from there being a deep, primordial difference between the Chinese and the "barbarians", viewed over centuries there was a long process by which groups moved across the frontier in either direction. Traditional Chinese texts on statecraft and government are shot through with adages about how to keep people within the remit of the state. The wall was one attempt to do so. The phrase "Han-traitor" was used to describe people who left the Han Chinese political system to go to live beyond its limits, where they immediately came to be seen as barbarians themselves. The stridency of official rhetoric about "barbarians" only gives us further notice of how serious a problem Chinese rulers saw this as been.

Frontiers - such as the frontier in the United States - have always been a place inhabited by outlaws, outsiders and marginal groups. China's northern frontier was no different. Refugees from political disputes, minority ethnic and religious groups, those evading taxes or debts, and even masses of ordinary citizens fleeing the demands of the state - all of these people could be tempted to flee to the areas where the Chinese state could not reach them. Such population movements on a large scale had been the death of not a few ancient states in Asia; indeed, much of south-east Asia was populated by groups that had fled the expansion of Chinese power in the south. The wall was an attempt to hem people in to the north. Lacking modern tools such as the telegraph and the railroad that allowed the American government to extend its control over a continent, ancient Chinese rulers feared the dispersal of their population beyond where they could serve the state.

Seen in this way, the Great Wall of China wasn't just a way to militarily defend against the north, it was also a way to defend against the social, economic and political lure of the northern frontier - to establish a sharp distinction between "us" and the barbarians which would discourage any Han Chinese thinking of going over to the land of the barbarians. It was a project not only of self-defence but also of state control; and only when one dynasty came to rule over all of the territory we now call China, and when China became so densely populated that there were fewer opportunities for anyone to run away from the state and start their own new community - only then did the Great Wall fall into disrepair.

For more detail on this theme, although not much discussion of the Chinese example, see James C. Scott, The Art of Not Being Governed: An Anarchist History of Upland Southeast Asia (New Haven, CT: Yale University Press, 2009).
