"We have to change the mind just a little bit to understand these people," he says.

Or as Liz Sotoodeh puts it, grimacing as the two of us huff up toward 13,779-foot Warmiwañusqa Pass, "I just wish I was pulling a boulder."

We carry almost nothing, and I try to keep this in mind as we climb. Actually I have felt surprisingly good since we hit the trail, a spring in my step I attribute partly to the running I did before the trip, partly to my decision to walk most of the trail. Certainly it's difficult to run, especially when the trail goes mountain-goat steep. But I walk mostly because running seems to defeat the purpose. Much of the Inca Trail to Machu Picchu is uneven stone; running requires careful attention to footing so as not to twist an ankle.

With such scenery erupting about us, it seems silly to stare at the ground, an attitude many of my companions adopt.

"The running is secondary to the culture," says Ed Wehan, who once ran 100 miles in nineteen hours but now moves at a mall- walker's pace. "You can picture the Incas, get a feel for the country by being out in it."

Run or walk, as we ascend toward Warmiwañusqa Pass, most of our group is rasping, one is barfing, and Ed is singing.

"Tiiiiired of living, but scaaared of dying, that old man river he just keeps on rollin' … ."

Cresting the pass is just part of our longest day, an eighteen-mile trek that takes us from our campsite at Llactapata to Phuyupatamarca, over three mountain passes, a trip that takes me about ten hours. This might sound like a grind but it isn't. We pass through villages where children light up when we pull colored pencils and berets from our packs; cloud forests thick with moss and cool shadow, and sprinkled with bright orchids and black butterflies; wide, grassy pampas; and, atop Warmiwañusqa Pass, a Scottish-moorlike scene in which a cold wind sends cannonballs of gray fog gusting past.

That evening, standing outside my tent at Phuyupatamarca, I watch the setting sun paint orange cloud swirls, then touch the snowy mountains soft pink. Later, over the rim of those same mountains, we see lightning detonate in bright explosions. Eddie points out the shapes of animals woven into the Milky Way while the cold stings our fingers.

"Just for us," he says.

This isn't entirely true. When we summit a last steep pitch of trail the next day and look down at Machu Picchu from the Gateway of the Sun, the lost city of the Incas has been found, by swarms of tourists in buses that belch their way up and down the mountain. The sun god sent man and woman to civilize the world, and they have done far too good a job of it.