The 9 Most Extreme Adventures in the World

From mountain biking to caving, here's a list of the hardest, the highest, the most challenging pursuits that athletes around the world aim to tame.

When extreme athletes want to test their mettle, they don’t go for a Sunday stroll. They embark on the world’s most extreme adventures, tackling the highest climbs, deepest dives, and roughest rapids on the planet. These adventures require advanced athletic achievement and a mastery of highly specialized skills—and they are not for the faint of heart.

The Most Epic Technical Mountain Bike Trail:
Portal Trail, Utah

Located on a 200-foot cliff above the Colorado River, the extreme exposure of this red rock route creates one of the most technical rides around. Riders pass a sign warning them to dismount in certain sections or risk a deadly plunge near an area where three riders have died.

This rugged trail, approximately two miles long, descends 1,050 feet, packing an average grade of 23 percent. This is the final ride in the “Magnificent 7” series of Moab-area trails.

The Highest Climb:
Denali, Alaska

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Denali—Mount McKinley—is North America’s highest mountain and one of the world’s most extreme climbs. Changing weather and crevasses are some of the many challenges climbers face on the way to the summit.

While everyone knows Mount Everest is the world's highest peak—though its exact height is being reevaluated by scientists this summer—it doesn’t offer the world’s greatest base-to-apex vertical. For that, you’ll have to travel to Alaska’s Denali.

Climbing North America’s highest mountain involves ascending nearly 18,000 feet from the base to the 20,310-foot summit. Along the way, expect to encounter Arctic conditions, glacier travel, crevasses, temperatures down to -35ºF, and winds whipping at over 100 miles an hour.

The climb usually takes three or four weeks, and over 90 percent of groups tackle the West Buttress route, though some prefer to hike in via the Muldrow Glacier or take the West Rib route.

The Most Epic Hike:
Snowman Trek, Bhutan

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The high-altitude hike typically takes 25 days of snowy conditions, but hikers are rewarded with epic views of the Himalayas.

With 48,000 feet of uphill hiking and 11 passes over 16,000 feet, this 186-mile trek is one of the world’s hardest hikes. And don’t expect a break from the altitude at night: The route involves camping at over 16,400 feet.

The Snowman Trek usually takes around 25 days, with some variations available, but it’s all rugged, high-altitude, remote terrain. Many attempt but don’t finish the trek due to snow conditions and problems with the altitude.

But it’s not all painful. The high-altitude Himalayan scenery, including passes such as Gangla Karchung La, Jaze La, and Rinchenzoe La, will enchant intrepid hikers along the way.

The Most Menacing Deep Dive:
Eagle's Nest, Florida

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Divers swim through caves over 300 feet deep at Eagle’s Nest in Florida.

Known as the Grand Canyon among divers, the Eagle's Nest cave complex features incredible scenery and caves over 300 feet deep. It’s located in Florida’s Chassahowitzka Wildlife Management Area near Weeki Wachee Springs State Park.

Despite their stunning beauty, the Eagle’s Nest caves lure many divers to their deaths. At least 10 have died here since 1981, and the site was closed from 1999 to 2003. Its remote location and extreme depth add to its danger, and this is an extreme experts-only dive.

The Most Challenging Skiing:
La Grave, France

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A skier sails through the snow at the expert-only La Grave resort in France. A cable car transports skiers 10, 500 feet to the top of the mountain for uninterrupted powder paths down. Guides are recommended to help avoid crevasses along the way.

A trip to La Grave involves taking a cable car up to 10,500 feet before skiing down mostly unmarked terrain, dodging crevasses and cliffs with the threat of avalanches along the way.

This isn't a regular resort; it's experts-only terrain packed with enough steep chutes, cliffs, and couloirs to keep highly skilled double black diamond off-piste skiers dreaming for years to come. Most of La Grave is unmarked and unpatrolled; if you're not careful, you might end up at the bottom of a crevasse. Hiring an experienced guide is highly recommended.

The Roughest River to Kayak:
Congo River’s Inga Rapids, Democratic Republic of the Congo

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Only one rafting team has ever survived paddling the Congo’s Inga Rapids. Waves as tall as 40 feet and other challenges greet rafters along the way. Steve Fisher, pictured here kayaking the dangerous rapids.

Only one team has successfully kayaked the Inga Rapids of the Congo River, but many others—including an entire team of seven in 1985—have died trying.

In 2011, Steve Fisher and his team, including paddlers Tyler Bradt, Benny Marr, and Rush Sturges, succeeded in kayaking the world’s biggest rapids with flows of up to 1.6 million cubic feet of water per second. They survived their attempt—just barely—and made an 80-minute documentary, Congo—The Grand Inga Project, about the journey.

The team faced 30-mile-an-hour water, 40-foot-tall waves, huge hydraulics, whirlpools, waterfalls, and the gargantuan task of arranging access in a politically unstable nation. Fisher was nominated as a National Geographic Adventurer of the Year for his efforts.

The Most Insane Cave to Explore:
Hang Son Doong, Vietnam

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Vietnam’s Hang Son Doong cave is the largest cave in the world. The cave is so staggering large that it has its own climate system. Visitors can take a six-hour trek through the jungle and explore the cave with a local tour operator.

Located in the World Heritage site of Phong Nha-Ke Bang National Park, Vietnam’s Son Doong Cave is so enormous it has its own climate, river, and jungle. At more than 2.5 miles long, it contains areas more than 600 feet tall, and is the largest cave in the world according to the British Cave Research Association.

Mesmerizing Drone Journey Into One of World’s Largest Caves

First explored in 2009, the limestone cave, which is part of a network of some 150 caves, has huge natural skylights and foliage where ceilings have collapsed, fast-flowing water, limestone cave pearls, and a 262-foot-tall stalagmite (the world’s largest).

It takes a six-hour jungle trek just to reach the mouth of the cave and a single tour company, Oxalis, is now allowed to bring in tourist expeditions.

The Most Thrilling Line to Walk:
Aiguille Dibona, French Alps

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Pablo Signoret is seen walking the longest slackline ever at Aiguille Dibona in the French Alps. Signoret joined Rafael Bridi and Guilherme Coury to set the world record for the longest highline at 9,842 feet elevation.

In 2016, slackliners Pablo Signoret, Rafael Bridi and Guilherme Coury trekked to Aiguille Dibona in the French Alps to set a record. Rigging a 656-foot-long slackline between two peaks, the trio set the record for the longest highline at 3,000 meters (9,842 feet) in elevation.

To complete this remote endeavor, they had to haul in packs (weighing up to 90 pounds) containing their climbing gear, webbing, camping supplies, food, and everything they needed to film, including a drone and GoPro cameras. High wind and lower levels of oxygen at elevation made their feat even more challenging.

The Hardest Waves to Tame:
Shipstern Bluff, Australia

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Shipstern Bluff draws top surfers to ride unpredictable waves that look like stairsteps, all while avoiding great white sharks that troll the waters.

South Pole storms from the “furious 50s” maximize the waves in this remote stretch of southeastern Tasmania. Surfers flock here to catch sets of 20-foot waves, but access isn’t easy; either a long hike or a lengthy boat ride is required. And in 2017, one of the nearby cliffs partially collapsed from the harsh weather and erosion, making the hike even more treacherous.

The Southern Ocean swell leads to unpredictable waves producing “stairsteps,” which surfers have to drop down as they surf—all while keeping an eye out for great white sharks.

Kristen Pope is a Wyoming based outdoor, adventure, and conservation writer. Follow her on Twitter @Kristen_E_Pope.