At Simatai, a two-hour drive from Beijing, there's an access point to the Great Wall, in north Miyun County. Three years ago, I hiked a dirt trail from this site's long-deserted turnstile entrance and scaled the wall's steep, crumbling steps. I felt I was conquering, not climbing, the Great Wall.
In the absence of known facts, many legends have buttressed the wall's lore. "The myths show that the earliest viewers of the wall from Europe [in the 1700s] really grappled with words to describe the immensity of the structure they saw," says William Lindesay, director of the International Friends of the Great Wall. "It was soon realized that there was no single summit from which viewers could survey the entire wall, hence imagination took to speculation." In the years that followed, the wall's length was estimated to be anywhere from about 1,500 to 31,250 miles. But the structure is actually multiple walls—dating from the 7th century B.C. to the 17th century A.D.—some of which are only now being surveyed. Current estimates place its length, with all the branches and sections, at 4,500 miles.
As the sun rose after a sleepless night at Simatai, I went from feeling like a big, bad adventurer to a blip in the wall's dark shadow. "It's the collective work of perhaps hundreds of millions of laborers," says Lindesay, who has trekked some 1,500 miles of it. "And it will probably never be surpassed in scale."