The Mongol attackers are long gone, but the vast brick-and-stone barrier that helped China repel them and other invaders still stands - and awaits a new horde of travelers who can explore and even camp out on the centuries-old fortification.
Crumbling in some areas and neatly restored in others, the Great Wall - actually a patchwork of walls - snakes over hills and through craggy ravines covering thousands of kilometers (miles) of Chinese countryside, dotted by watchtowers once manned by Ming dynasty sentinels.
Some of the towers, where enterprising Chinese today guard only souvenir stands, have sprung back to life as something akin to modern-day hostels, sheltering hikers who come for overnight trips to soak up history and vistas of former battlefields now carpeted with vegetation.
Sun Hailong, a Chinese guide of Mongol ancestry, rents one of the towers about 140 kilometers (87 miles) northeast of the Chinese capital, Beijing, and takes visitors who want to spend the night - by pitching a tent or simply unfurling a sleeping bag - in its crenelated confines.
Visiting mainland China for the first time with my father, who had flown in from the United States, I arranged through a Beijing-based friend to meet Sun near Jinshanling, the section of the wall where he lives with his family.
We arrived late one afternoon after riding for three hours in a minibus crowded with cigarette-puffing locals. Along the way, we passed scenes of rural life - ruddy-faced farmers sitting on their haunches outside brick houses, firewood stacked high, herds of sheep.
The van left us on a desolate stretch of highway, at the mouth of a road spanned by an immense stone gateway that marked the entrance to Jinshanling. Sun greeted us there, grinning and urging my father and I to climb into the back of his three-wheeled motorcycle.
"Today, the sunset will be beautiful," said Sun, a mustachioed 37-year-old who wore a T-shirt, dark blue trousers and traditional black cotton shoes.
After riding uphill for several kilometers (miles), we arrived at Sun's house and souvenir shop, dropped off our bags and continued on foot to the wall, which stood like a medieval fortress in the distance.
We clambered up stone stairs, traversed a sagebrush-covered hillside and entered a keyhole-like door the base of the Jinshanling wall, which is partially restored but less touristed than areas such as Badaling, which former U.S. President Richard Nixon visited in 1972.
Inside the rampart, we could see the wall's hodgepodge construction over many centuries: older brown bricks were nested in gritty mortar alongside clean dark gray ones used by restorers in recent decades.
Ming dynasty rulers began construction of the Jinshanling wall - roughly as it exists today, with strategic holes and chutes for weaponry and watchtowers - in response to raids by bow-and-arrow-wielding Mongols in the 1500s.
Their soldiers and artisans used bricks as a facing for a stone-and-mortar wall erected after a 1550 attack by Mongol horsemen, according to David Spindler, an independent scholar who has been researching the wall around Beijing for several years. It was bolstered by brick ramparts.
But the wall's history likely stretches back further.
"Another section of wall in the Jinshanling area, parallel to the current wall, may have been built by the Northern Qi dynasty," which ruled from 550 to 577 A.D., Spindler added.
The Jinshanling wall, now almost silent except for the squawks of pheasants, was once the scene of a historic battle between Chinese forces and Mongol fighters in October 1554.
But the Chinese overwhelmed the Mongols in just three days.
"The Mongols and their horses ran out of food and had to call off their attack," said Spindler, who added that Jinshanling was vulnerable to enemy raids because it was a low-lying area.
The ascent to Jinshanling took us less than an hour, though the climb was at times steep and the footing shaky. From one point, we watched the sun set behind mountaintops before hiking back to Sun's house for a meal of dumplings, stir-fried vegetables and glasses of beer.
Then we pulled on fleece jackets as the night got colder and, with flashlights beaming, headed into darkness to return to the wall for the night.
Under a nearly full moon, we traipsed along some of the wall's narrow walkways, through shadowy passageways and over several steep humps along the wall's spine. It was eerily still, except for the flashes of a photographer's camera in the distance.
We arrived at Sun's watchtower, where we decided to sleep under the stars, outside the tower's box-like stone house.
Sun laid out a tarpaulin and sleeping bags for us while we brushed our teeth by leaning over the crenels where Chinese sentries might have hurled stones at marauders below.
We slept - somewhat uncomfortably in the chill air - until the sun rose early the next morning over the saw-tooth horizon. Sun made us a simple breakfast of instant noodles, which we slurped down eagerly.
We spent half the next day hiking 10 kilometers (6.2 miles) of the Great Wall - over loose stones and along paths that skirted weak or collapsed sections - to Simatai, another stretch with steeper inclines - and more tourists.
Although annoyingly persistent hawkers followed us at times, trying to peddle bottled water and postcards, we were virtually alone on the Jinshanling wall. Like a narrow and dilapidated cobbled street, it led us through tumbledown watchtowers and over small mountain peaks.
But the enchanting solitude of Jinshanling ended abruptly at Simatai, where crowds of tourists were disembarking from tour buses and swarming around amusements such as a trolley across a river gulch, restaurants and a cable car that carries passengers up a mountainside.
With the widely touted 2008 Beijing Olympics on the horizon and bigger crowds expected, the seclusion we experienced at the Jinshanling wall - with its sweeping views, abandoned battlements and pristine countryside - may become harder to find.
Better to visit before the next invasion.
If you go:
GETTING THERE: From Beijing, take a bus from Dongzhimen station to Miyun, then take another bus to Gubeikou and get off at the Jinshanling gate. Trains are also available to Gubeikou.
COST: There is a 40 yuan (US $5,euro 4) entrance fee for each traveler at the Jinshanling Wall. Sun Hailong's overnight service costs 200 yuan (US $24, euro 20) per person per night and includes dinner and breakfast.
CURRENCY: The Chinese yuan is the official currency (8.09 yuan to one U.S. dollar). There are currency exchange facilities in Beijing.
GETTING BY: English is not widely spoken, so the services of a guide or translator may be useful.
WHEN TO GO: The temperatures are most comfortable in September and October and in the spring.
WHAT TO BRING: Sturdy shoes or boots and clothing suitable for hiking and cooler weather.
INFORMATION: Sun Hailong speaks Chinese and some English. He can be reached by mobile telephone at (011) 86-139-3244-4368.
FOR MORE INFORMATION: The Beijing Guide, http://www.thebeijingguide.com/great_wall_of_china/accommodation_great_ all _of_china.html.