Beyond—way beyond—the piazzas, the museums, and the foie gras there's a wild side to the Old World. Beginning with Joe Kane cutting loose in the Spanish Pyrenees, our limber reporters go dogsledding, kayaking, biking, diving, hiking, and trekking into off-road nirvanas

I didn't condescend to visit continental Europe until I reached middle age. As a young man, I went south, into Latin America, chasing Indians, guerrillas, big mountains, wild rivers, trackless forests. What could the light in Paris have over the light in the Andes? Europe was tame, civilized, petrified. Europe was museums and cities. Europe could wait.

And wait it did, for twenty-five years, until the summer I spoke at a kayak festival in Sort, the cultural capital of the Pallars Sobirà region, in northwest Catalonia. Sort straddles the Noguera Pallaresa, the most powerful river in the Pyrenees, and has a white-water tradition that goes back four decades—a slalom course runs the length of town, and on the streets, black-shawled old women rub shoulders with neoprened young men fueled on adrenaline and good local wine. In fact, the Noguera Pallaresa Valley has become Spain's leading center for adventure recreation of every stripe. You can raft, mountain bike, bag high peaks, rock climb, ski, snowshoe, ride horses, and indulge pretty much any other extreme-sport fantasy you might choose to wave a credit card at, including paragliding, bungee jumping, and hot-air ballooning.

I fell in love with the river, the cobblestoned villages, the people, and the food—as earthy as the land itself. And near the top of the river, in Aigüestortes National Park—a spectacular landscape of waterfalls, lakes, and craggy ridges—I lost my heart to a 9,442-foot mountain called Monestero.

Monestero is one of the park's highest peaks, but it's a walk-up route—a long day-hike up a beautiful alpine valley, then a scramble through a field of scree that spills down the mountain like a granite skirt. For an aging boomer with Tinkertoy knees, it offered a combination of challenge and reward that seemed just about perfect. Like the Noguera Pallaresa Valley, Monestero came to represent a Europe I'd finally grown into. I had time on that trip to hike only within sight of the peak, but a year later, I went back to climb it.

I planned to immerse myself in the Noguera Pallaresa environs for two weeks. Raft the river, bike the hills, hike the national park. To acclimate, I'd spend a couple of days walking the trails that run among the villages in the valley.

I went in mid-September, when tourists visit mainly on weekends and the mountain passes are usually free of snow. From Barcelona I drove four hours north, winding through sunny plains, then ascending sharply into the slot where the Noguera Pallaresa canyon spills into the lowlands. In Sort (Catalan for "luck"), I got a room at the rambling Hotel Pessets, where I had the entire third floor to myself.

In the morning, I walked two blocks to a shady lane walled by four-story stone buildings and astonished the butcher by ordering a football field of serrano ham ("Did I say meters? Make that grams"). I bought bread and a waxed wheel of local goat cheese cured in wild herbs. Then I hiked south along the river, past a cornfield and a poplar copse, turned left at a creek, and started uphill on a trail marked by painted yellow circles that peered from trees and rocks like smiley faces.