Crested Butte When the rides start at 9,000 feet and go up, you know you're in a special place. The routes surrounding this Colorado town, called CB by locals, take you on singletrack through groves of aspens, on wide-open trails through meadows of skunk cabbage and sage, and over rocky mining roads across the Continental Divide. Trail 401 and Trail 403 are not to be missed, and the descent of Teocali Ridge is one of the best mountain bike rides in the world. For those looking for an epic experience, try riding from CB to Aspen and back. And don't miss the Mountain Bike Hall of Fame in town.
Best Time to Go: Summer, especially for Fat Tire Bike Week, the world's oldest mountain bike festival, at the end of June. But be prepared for afternoon thunderstorms.
It's Most Fun If You're This Fit: High-volume lungs will be able to make the most of the high-mountain paths, but fun, short, nontechnical trails loop around town for novices.
Get There With: Crested Butte Mountain Guides Day Tour, June-Sept., $100;www.crestedbutteguides.com
Madonna di Ghisallo In 1948, a modest chapel on the shores of Italy's Lago di Como was christened in honor of the Madonna di Ghisallo, a saint dedicated to the safety and well-being of cyclists. (Shown here is the brass memorial outside the chapel.) Since then, this tiny sanctuary has become a museum of those who have sought its blessings: Leader jerseys from the Giro d'Italia and Tour de France (as well as those left by amateurs) adorn the walls, and all around are vintage bicycles from legends such as Fausto Coppi, Gino Bartali and Eddy Merckx. There's even a bike from Alfonsina Strada, the first and only woman to ride in the Giro. The surrounding roads are spectacular, but the highlight might be the Wall of Sormano, a gnarly stretch of tarmac whose 1.5 miles of 18-percent grade was used to sort the champions from the fodder in the sport's earliest races.
Best Time to Go: Moderate elevation and climate make this a year-round destination, but the Tour of Lombardy passes by in early October.
It's Most Fun If You're This Fit: Moderately fit, riding at least three times a week and prepared to climb. The ascent from from Bellagio to the church is about 3 miles at 9-10 percent.Get There With: Cycle Italia's Legendary Climbs tour, July 8-16, $2,895; www.cycleitalia.com
Alpe d'Huez Since its first inclusion in the Tour de France, in 1952, when Italian campionissimo Fausto Coppi climbed to victory, a win atop this 21-switchback ascent has become the most coveted prize in the Grand Tours. It's also the most manic stage of any Tour de France in which it's included. Each turn has a sign commemorating one of the stage winners. (Coppi and Armstrong share a spot on switchback 21.) So popular is this 8-mile climb that photographers stake out the road every day in the summer to sell photos to passing riders.
Best Time to Go: Late spring through early fall for riding-but if you're into crowds, bring camping gear or rent a van and arrive days early to secure a site to watch the Tour.
It's Most Fun If You're This Fit: With an average grade of only about 8 percent, this Alp isn't crushing-it's the storied battles between pros that give it notoriety. If you're not trying to race up it at 15 mph, even a moderately fit recreational rider should enjoy summiting.
Get There With: Breaking Away Bicycling Tours' Tour de Alpes, July 14-22, $3,198;www.breakingaway.com
Napa & Sonoma Valleys Perhaps because pasta, the cornerstone of the cycling diet, virtually demands to be enjoyed with wine, these adjacent wine-country regions in northern California have become synonymous with good riding-so much so that if you live in the U.S. you might be surprised at how popular our native vineyards have become with foreign cyclists. Napa and Sonoma are not merely local favorites; they're legitimate international must-rides. The varied terrain can satisfy everyone from the flat-seeking novice to the hard-core hammerhead. The roads are lightly traveled. The cuisine maintains its gourmet appeal while ranging in price from cheap basics to outrageously expensive feasts. And there's a wine tasting, it seems, on every mile.
Best Time to Go: Anytime-that's the beauty of it.
It's Most Fun If You're This Fit: With the variety of terrain available, readiness to eat and drink is more important than cycling preparedness. Climbs such as Spring Mountain, Skagg's Springs and Oakville Grade will turn sinewy steel bands of muscle into tapioca. West Dry Creek Road, River Road and Silverado Trail are relaxing rambles.
Get There With: Backroads California wine-country tours, year-round, $1,998-$2,598;www.backroads.com