If you like smoking mountains, Stromboli is the place to go. The best known of several active volcanic islands located north of Sicily, this conical vision rising straight out of the sea is as unpredictable as the weather. In order to trek through this unique landscape, you must join a guided tour, most of which head off on the strenuous three-hour climb in the late afternoon. Once near the summit, you enjoy a Mediterranean sunset and return as darkness falls. In the heat of the summer, however, some tours also go up at night and come down in the early morning. The cost can be as low as $16.

For more information: Wiki Travel

With 300,000 people crowding Japan's Mt. Fuji during its relatively short summer climbing season, this adventure is as much of a social affair as it is a communion with nature. In fact, mountaineer Greg Slayden says that Fuji, a volcanic slag heap, is far more beautiful when you regard it from afar than when you're standing on it. Most hikers head part of the way up on day one and sleep for several hours in one of many huts (reservations required) before setting out in the middle of the night hoping to see a legendary red sunrise. An hour-long circumnavigation of the crater is usually part of the journey. Routes from the foot of the mountain are becoming more popular and feature shrines and teahouses along the way, but you'll need two extra days to complete the journey. To avoid the worst of the crowds, take Slayden's advice and pick weekdays in late June or July, when many Japanese seem to think the mountain is "closed."

For More Information: Japan Guide

Kilimanjaro is totally walkable, but due to the altitude, trekkers take it slow, leaving time for acclimatization. Your week-long journey to the summit will be one of the toughest physical challenges of your life. As you pass through five climatic zones on your way up, you'll suffer from heat, cold, altitude and exhaustion. It's critical (and mandatory) to book a guided tour complete with porters and cooks. Expect to pay up to $5,000 to do it right, not including all the gear and clothing your tour company will recommend. Your ultimate reward: a sunrise visit to the Uhuru summit, where all of Africa spreads out before you. The best times to go are January through March and September through October.

For more information: Climbing Kilimanjaro and Tanzania Odyssey

The tallest mountain in the Western Hemisphere isn't Mt. McKinley, it's Argentina's Cerro Aconcagua, an Andean peak that's also the tallest mountain in the Southern Hemisphere. Amazingly, though, non-technical climbers who are in good shape can easily make it to the top on a guided trek (about $4,000) that typically takes three weeks from arrival in Argentina to departure. The usual route, from the north via the Vacas Valley, passes through Aconcagua Provincial Park, where glaciers and dramatic peaks and valleys abound. The final push starts from a base camp at 14,340 feet that offers meal tents, showers, even internet access. Look for a tour that includes time for several summit attempts, since bad weather and wind near the top can pin down climbers for days at a time. Most treks set off during the South American summer: January and February.

For more information: Natural High Alpine

The May 19, 1980, eruption of Mount St. Helens turned an impressive swath of southwest Washington state into a moonscape. A generation later, nature has rebounded and the mountain is slowly but surely rebuilding itself as lava pushes up from the center of the earth. From the Climbers Bivouac, it's a five-mile hike to the crater's rim. The round trip can take from seven to 12 hours, so it's best to set out early in the day, especially in the peak summer climbing season. A $22 permit is required to climb from April 1 through October 31, and the number of permits is limited in the summer months, so plan in advance. "This is a really dusty, ashy climb in the summer," says Greg Slayden. "It's better when there's snow on the slopes and you can slide down on your butt or your feet or even ski down."

For more information: U.S. Forest Service

The drama of Haleakala isn't in the ascent. After all, you can drive all the way to the top, covering 10,000 vertical feet in 38 miles. Once there, however, numerous hikes will give you an amazing view into the massive caldera that's seven miles long, two miles wide and 2,600 feet deep. Hikers at the summit also enjoy the Skyline Trail, a 6.8-mile walk that on a clear day offers sweeping views all the way to neighboring Hawaiian islands. Another walk, to the amazingly named Ka Luu o Ka Oo cinder cone, takes about half a day. For a real thrill, rent a bike and coast all the way from the summit back down to the ocean. Imagine riding a bike 40 miles through paradise without having to pedal. Sounds like a fun afternoon.

For more information: National Park Service

A two-day adventure to Kinabalu (guides are mandatory) is the world's most accessible tropical mountain climb. You begin in a cool cloud forest, keeping your eyes open for 800 species of orchids and 600 types of ferns, not to mention the area's unique, insect-eating pitcher plants. The first part of the hike starts at Kinabalu Park headquarters at 5,128 feet and rises to the well-equipped Laban Rata hut and rest stop at 10,800 feet. The next day, it's a two- to four-hour final push to the summit at Low's Peak. "It's easy, little more than a walk," says Greg Slayden. The return hike takes about five hours.

For more information: Endemic Guides

As the only 14,000-foot peak within Colorado's Rocky Mountain National Park, the easily accessed Longs Peak is popular with day climbers. A pre-dawn departure along the 7.5-mile Keyhole Route will get you to the summit in time to enjoy the view and return to the tree line before the frequent afternoon storms (during summer) arrive. You'll climb 5,000 vertical feet on your way to the broad, flat summit; exhaustion and altitude sickness may kick in if you overexert yourself. "There's so much great terrain in the Rockies," says Greg Slayden. "This is a good peak because it can force scramblers to push their limits a little bit."

For more information: National Park Service

One of the most photographed mountains in the world, Huayna Picchu is the rounded mountain rising dramatically behind the ruins of Machu Picchu. Although at first glance it looks nearly vertical and utterly unclimbable, but it's actually quite accessible. Each day, hundreds of climbers sign up to tackle its exhausting series of switchbacks, stairs and ladders. (Get there by 8 a.m. to avoid crowds.) After 90 minutes of huffing and puffing—and a few crawls through short but slightly claustrophobic caves—you emerge on the small, boulder-strewn summit. The view is unforgettable—jagged Andean peaks in the distance and the entire Machu Picchu complex some 1,200 feet straight down.

For more information: VirtualTourist.com

California's Mt. Whitney is the highest mountain in the contiguous 48 states and the crowning glory of the Sierra Nevada range. During the summer season, the popular "regular trail" from the Whitney Portal parking lot will take you on a seven-hour journey to the summit. Some hardcore trekkers grumble that this trail is actually too easy, graded so flat and with so many switchbacks that it's longer (at 10.5 miles) than it needs to be. Nevertheless, the scenery is stunning, especially during sunrise hours as you commence your trip and gaze up at the peaks glowing red and orange. You must acquire a permit via lottery to hike the regular trail during the summer.

For more information: U.S. Forest Service