The craziest adventure trips on Earth

A century ago, most of the planet's residents never managed to make it farther than a few hundred miles from their birthplaces. Now, with one billion international arrivals a year, travelers are spreading into the last unexplored corners of the globe. The demand for bigger, better and more adventurous experiences is skyrocketing. "There's an accessibility that there never was before, and people can do things that were once unimaginable," says Shannon Stowell, president of the Adventure Travel Trade Association.

Here are nine of the most extreme trips on the planet — and the outfitters that take adventurers over the edge and back again.

Ski to the North Pole.

No one would call skiing to the South Pole a cop-out, but a far more challenging prospect awaits on the other end of the axis. Whereas the South Pole journey is a long, hard, and boring slog over a frozen continent, the approach to the North Pole is an infuriating maze of ever-shifting pack ice.

"That's what we call the polar treadmill," says Annie Aggens, a guide with Polar Explorers, which pioneered commercial polar skiing expeditions in the nineties. "You're actually drifting with the currents and the wind. Overnight, you may have drifted one mile or even up to 10 miles and frequently you're moving away from the pole."

The upside? With the changing scenery, skiers don't usually get bored. They do, however, get tired. It can take upwards of 50 days to ski from Resolute Bay, Canada, to the pole, dodging polar bears, enduring temperatures that rarely peek out of the minuses, and driving into bone-freezing winds. But for those who learn cold-weather skills and develop the mental and physical stamina to pull a 150-pound sled every day for nearly two months, there are unspeakable rewards like rare, silent landscapes that few people will ever have the strength or resolve to see.

More Information: Full North Pole expeditions with Polar Explorers start at about $100,000 and include a five-day training program and all group equipment, skis and sleeping gear.

Row across an ocean.

When Leven Brown rowed solo across the Atlantic Ocean in 2005, he battled four hurricanes, lost 70 pounds and set a world record. He liked it so much that he decided to row across the ocean again, but this time, he wanted to take some friends and cut down on the $150,000 price tag. So in 2006, the portly, bearded British skipper founded Ocean Row Events, a company that arranges rowing expeditions across oceans and other extremely large bodies of water. Since then, Brown has organized six trans-ocean rowing trips and set seven world records, including the fastest crossing of the North Atlantic and the longest distance rowed in 24 hours.

Surprisingly, what it takes to row an ocean isn't necessarily big quadriceps, rowing skills or even expedition experience.

"Character, character, character," says Brown. "We call it the X factor" — or what translates loosely to an ability to withstand a lot of pain and tedium on a boat the size of a bedroom without getting into a fistfight with any of your seven crewmates.

Most people burn about 10,000 calories a day and lose a minimum of 30 pounds, endure plagues of salt-infested blisters and tolerate the ever-present threat of 40-foot storm swells, lurking marine creatures and passing freighters. There are reasons rowers believe it's all worth it, such as seeing thousands-strong pods of dolphins and watching millions of stars spread across an unbroken sky. There is the preternatural stillness of the sea on a calm day, not to mention the joy of making it back to shore.

More information: Ocean Row Events'

next transatlantic row will take place in January 2014 and costs

£15,000 (about $24,000). Most rowers raise the funds through corporate

sponsorships.

Visit the dark side of the moon.

Less than 50 years after Neil Armstrong became the first human to hop around on the Moon, tickets to our celestial carriage house are about to go on sale. Since 1998, Virginia-based Space Adventures has brokered rides for the extremely wealthy on Russian Soyuz space shuttles headed to the International Space Station.

Now the company has an even more outrageous plan: Shuttle two passengers to the far side of the Moon to watch the earth rise. Although the price tag is suitably stratospheric – $150 million – the second ticket just sold and the as-yet-unnamed passengers should arrive in early 2017.

The experience isn't just a monetary commitment. Passengers must pass a rigorous medical exam, then go through weeks of training at Star City, Russia's cosmonaut facility. "Our clients are all very pleasantly surprised with how relatively simple it all is," says Space Adventures President Tom Shelley.

Like the company's previous expeditions, the lunar mission will take passengers to the International Space Station for about 10 days. Instead of returning, however, they'll continue toward the moon, watching the Earth shrink into a blue dot over four days. On the far side of the orb, the spacecraft will skim over the mountains, and passengers will watch the Earth creep above the lunar horizon.

More Information: If Space Adventures' first lunar mission is a success, the company will arrange subsequent journeys for about $150 million per person. Its orbital and suborbital spaceflights aboard Soyuz spacecraft, including all training, starting at about $50 million.

Climb Mt. Everest.

About 60 years ago, Edmund Hillary and Tenzing Norgay climbed through icefalls, endured a blizzard and kicked steps into walls of ice and rock to become the first people to summit Mt. Everest. Since then, about 4,000 have and successfully reached the peak of the world's tallest mountain. Today, guide services regularly lead amateur mountaineers to the top.

Better weather forecasting and gear innovation mean more people than ever are flocking to Mt. Everest, but that doesn't mean that summiting isn't still a worthwhile – and risky – challenge for anyone serious about a bucket list. For about 90 percent of those who attempt the mountain, the first step is to pick the right guide service.

One good choice: RMI Expeditions, which counts Dave Hahn, who has summited 15 times, and Seth Waterfall, who has summited three, among its lead guides. The outfitter trains prospective climbers on smaller peaks before leading them on a 70-plus-day expedition to base camp and up the mountain.

"Everest is like any other mountain but with more magnified risk," says Waterfall. "We guides try to mitigate as much of the risk as possible, but we can't eliminate it. There's a certain need for acceptance." But perhaps the uncertainty and risk of climbing the world's tallest mountain are a large part of Everest's enduring allure.

More Information: An expedition to the summit of Mt. Everest with RMI Guides costs $65,000 and takes place between March and June each year. It can take about two years for guides to walk qualified clients through the training and preparation.

Scuba dive with crocodiles.

Africa's Nile crocodiles don't grow to more than a 1,000 pounds by being discerning about what they eat. So if you're going to scuba dive with these primordial reptiles, there are a few important things to know:

First, crocodiles have terrible eyesight, which means they typically hunt at the surface, where they can spot prey in silhouette against a bright background. Second, they become sluggish and reclusive in cold water, which means the safest time to see them in Botswana's Okavango Delta, where they number in the thousands, is in July and August, when the water is high, cold and clear.

That said, it's not easy – or free of risk – to swim with these ancient beasts. "They're very hard to see because they look like pieces of wood," says Amos Nachoum, a Brillo-haired Israeli wildlife photographer and president of Big Animals Expeditions, a company that takes groups to see predators like sharks, leopard seals, and snow leopards without cages or protective gear.

Why would anyone voluntarily pursue such an encounter? While it may not take a lot of skill – divers must be moderately fit, able to dive in strong currents, and have an ample supply of nerve – diving with crocodiles is, undoubtedly, a singular experience. "From the moment I decide to roll back into the water, the sense of fascination and adrenaline is taking over," Nachoum says. "The excitement and the rush pushes me closer toward the croc until I am so close the camera cannot focus anymore – only 10 inches face to face. That is transcendence."

More Information: Big Animals Expeditions' next trip to Botswana to dive with crocodiles is June 28–July 7, 2014 and costs $14,900.

Explore North Korea.

Though they're busy constantly threatening nuclear war, maintaining a secretive totalitarian state and quashing dissent among the citizenry, leaders of the Democratic People's Republic of North Korea (DPRNK) always find the time to welcome foreign visitors and currency.

The country's total international arrivals – not counting Chinese – number fewer than 6,000 most years; even so, North Korea's leaders have long made encouraging tourism a priority. This is the paradox in which the MIR Corporation, a respected American outfitter offering several new trips into the DPRNK, now operates.

MIR's founder, Douglas Grimes, began his career as a welcoming committee for tourists visiting America's political adversaries three decades ago with a series of volleyball games between traveling Yankees and USSR loyalists. Since then, MIR has taken skiers, climbers and other adventurous travelers into some of Europe and Asia's most difficult-to-access regions. Grimes says North Korea doesn't quite live up to its reputation as a bizarre, dangerous hellhole. On his scouting trip, Grimes says, he found pastoral agricultural areas and an immaculate, even pretty, capital. "I didn't feel like people weren't happy, which I was kind of expecting," he says.

Some critics question the ethics of supporting a country – everything is government operated – with a questionable-at-best human rights record and shaky relations with the U.S. But interacting with a truly foreign culture is always a worthwhile experience, even under the watchful eye of a government minder.

More Information: MIR Corporation handles the incredibly complicated process of applying for and receiving a visa for its clients. The company's first North Korea trip will visit Beijing, Pyongyang, several mountain parks and the DMZ over 11 days ($5,195, plus $650 for round-trip flights from Beijing and Pyongyang).

Take a MiG trip.

There are only a few ways a person can get a ride in a fighter jet. One is to join the Air Force. Another is to save up about $20,000 and travel to the Sokol Airbase in Nizhny Novgorod, Russia, for one of the few commercial fighter jet rides on the planet. "Riding a motorcycle at 145 miles per hour is like riding a tricycle compared to this," says Paul Cusma, a financial adviser from Tampa who flew in 2009 on a trip arranged by Florida-based outfitter Incredible Adventures, which has organized flights for well-heeled adrenaline addicts since 1993.

On flight day, you'll need to pass a medical test. Once everyone is sure you're not going to have a heart attack, you'll be handed a pressure suit, a helmet and a custom-fitted oxygen mask. A briefing on safety procedures – what not to touch, what to do in case of ejection – follows.

Then comes the fun part. Climb into a MiG-29 and hold on while the pilot loops and rolls up to 18,000 feet. Withstand as much as 7 G's of force, travel faster than the speed of sound, and, if you have a pilot's license, consider taking the controls for a few moments. Another option: Have the pilot tilt the nose up and ascend to nearly 70,000 feet to see the curvature of the earth and the eerie blackness of space beyond.

More Information: Incredible Adventures' five-day MiG Over Moscow trip to Russia, including luxury hotels, breakfasts and one flight in a MiG-29, starts at $21,000.

Charter a submarine.

If you're considering purchasing a personal submersible for your yacht, there is only one man in the world you'd want to build it. Graham Hawkes has been designing and producing custom submarines for many decades.

His most famous work remains the DeepFlight Challenger, which the late Steve Fossett commissioned and Richard Branson funded to race James Cameron to the bottom of the Marianas Trench.

The Super Falcon is – as far as these things go – a far more practical manned submersible.

Currently for sale on a custom basis and for weeklong charters, this underwater plane doesn't yet take commercial passengers due to regulatory constraints, but Hawkes' company does offer underwater pilot training courses. And Red Bull co-founder Dietrich Mateschitz is considering providing rides in his Falcon to guests at Laucala, his private island resort in Fiji.

Nearly 21 feet long, the Super Falcon has two cockpits and resembles a tiny, futuristic plane. Unlike submersibles that troll the ocean floor, this one flies above it. As a pilot, you can perform rolls, explode up from the surface like a space-age whale and sidle up to great white sharks that, Hawkes says, view the sub as one of their kind. Want to go deeper?

No problem. Follow whales' songs 500 feet down and circle pods of resting humpbacks.

More Information: Chartering a Super Falcon from DeepFlight starts at about $50,000 per week.

Raft remote rivers.

Global Descents made a big splash in the rafting game by being the first company to offer amateurs access to remote rivers like India's raging Zanskar and Madagascar's remote Matsiatra. Never particularly profit-oriented, the company's founders tend to tackle the nearly impossible with a sort of rebellious glee. "We're river runners much more than businessmen," says owner Matt Gontram. "We're all about running rivers, so if someone calls me and says, Hey, I've always wanted to go do this river in Argentina – or anywhere – we'd say, Let's go down and do it."

Gontram's next project, the Usumacinta River, is a rapid-studded fire hose that marks the border between Mexico and Guatemala.

Once the territory of Sandinistas, it has been off-limits for years, even though the conflict in Chiapas has quieted down. Though the rapids generally don't exceed Class III, the adventure quotient is high. It's one of the continent’s biggest rivers, flowing at 40,000 to 100,000 cubic feet per second (the Colorado River does between 8,000 and 25,000 cfs through the Grand Canyon), and gigantic eddies and whirlpools flip boats like pancakes.

But what is most interesting lies on shore.

Rafters camp on empty beaches larger than football fields, then explore travertine pools and waterfalls the color of Windex before checking out ancient Mayan ruins abandoned deep in the jungle.

More Information: Global Descents' first raft trip down Mexico's Usumacinta River runs about $1,750.

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