I CALL A HALT and set the video to capture the scene. After three days of clear weather, broken curtains of low clouds chase across the wooded slopes of Thunderhead Mountain in the distance. The rising wind brings a damp chill, and our team begins unpacking rain gear. No one hurries. Ever since entering Great Smoky Mountains National Park, my Chinese comrades and I have progressively lost respect for this manicured "wilderness" in the Appalachian Range. It's nothing like the random challenges of the mountains back home, where trails are maintained only to the extent that local peasants find them useful. Here the trail is in such perfect condition that I feel like giving it a tip. There are signposts everywhere, and the maps are a revelation: in China, I'm sure only the army and Taiwanese spies could hope to have anything so detailed, and I'm willing to bet that the Chinese People's Liberation Army hasn't started marking the locations of toilets yet.

I pull on my hard shell as the first drops of rain splash off pack covers. Less than half a minute later, the sky explodes.

Chairman Mao once wrote about an "upturned bowl of rain." As if to say, "Diss this, Chinese man," something more like an upturned barrel of hailstones hits our crew. Dazzled and deafened by a terrifying burst of lightning and thunder, we stumble for cover—only to find the trail growing increasingly exposed. The hailstones give way to a relentless tattoo of heavy raindrops. As we reach open ground on the approach to Rocky Top, a barren western peak of Thunderhead Mountain, we pause under the last trees and count the seconds between lightning flashes and thunderclaps: "Six … eight … ten—good enough!" Then we run for it.

WE ARRIVED A FEW DAYS AGO from Beijing and were greeted by a notice on the doors at Knoxville, Tennessee's tiny airport announcing that the terrorist threat level was orange. Serious stuff, apparently, but not serious enough to warrant placing any security on the baggage claim, where anyone could wander in and take a new piece of luggage.

The airport's faith in the good character of the local citizenry was not shared by the burly African-American driver who helped us into his taxi. He wasn't happy about our choice of lodging.

"That's a pretty rough part of town," he said.

Rough?

"Yeah, it's full of homeless people, drug addicts, prostitutes …"