1. Shark Cage Diving (South Africa)
Picture this: Great white sharks encircle your boat, gnashing their teeth ferociously. It's feeding time. And you're about to jump right in. For $120, Great White Tours will lower you into the shark-infested waters – in a metal cage, that is. Hold on tight as the shark's tail thrashes against the cage. As you gaze into the shark’s eyes, pray that those steel bars hold up.

(Offered by tour operators based in Cape Town, South Africa. http://www.sharkcagediving.net about $115 per session)

2. Run with Bulls (Spain)
This one’s a perennial favorite: known as “El Encerrio” in Spanish (which literally means “the closing”) the bulls are let loose on the streets of Pamplona for the culmination of the San Fermin festival. Pick your entry and exit streets in advance. The rockets go off – signaling the release of the bulls – and your heart rate goes up. Assume position. You hear the bulls approaching. You dash madly into the streets, joining the stampede of inebriated people as they, too, sprint away from the angry bulls. If you haven’t been gored, finish off the day sipping a congratulatory beer in the Plaza de Toros bullring.

3. Stay in the Ice Hotel (Sweden)
We’re not sure what’s more impressive: that a hotel exists that is entirely made of ice, or that the Ice Hotel is remade annually, with each of its forty rooms carefully sculpted by world-renowned artists. This frozen hotel, located in the village of Jukkasjärvi, comes replete with a church (just in case you were thinking of tying the knot) and an Absolut Vodka Bar. At night, sleep on comfy reindeer skins atop the ice beds. During the day, the hotel offers adventure for every style: snowmobiling, dogsledding, or following moosetracks above the Artic circle. Skol!

(http://www.icehotel.com, prices vary according to room)

4. Float on the Dead Sea (Israel, Jordan)
The Dead Sea is famous for being the lowest point on the planet – at a whopping four hundred and twenty meters below sea level – but that’s not the only reason to check out this hot spot. The oily waters are so rich in salt that everything floats – including you. You can forget about doing laps! For an extra-refreshing treat, rub mineral-rich mud on your body – or have someone do it for you at one of the many high-end spas that line the shores.

5. Sea Kayak on Greenland’s Fjords (Greenland)
What better way to see Greenland’s (rapidly melting) icebergs than to glide past in a sea kayak? If you’re lucky, you’ll catch glimpses of seals, whales, and other Arctic wildlife. And those earth-shattering rumbling and groaning noises? Don’t fret, that’s just the sound of icebergs straining under their own weight and colliding with neighboring bergs. Can be done as a day expedition, but if you want to get off-the-beaten-track, opt for the multi-day excursions.

(Tours operated by www.blackfeather.com , www.southernseaventures.com , http://www.expeditiongreenland.com)

6. Trans-Siberian Railroad (Asia)
Fancy the idea of crossing an entire continent – by train? The longest train journey in the world runs across Northern Asia, from Moscow to Vladivostok, but most opt to end in Beijing. From Moscow, take the five-day train to the remote town of Irkutsk, gazing out at the vast Siberian steppes as you head into the most landlocked place on earth. From there, it’s two days by train to Ulan Bator, the capital of Mongolia. Take a break and tour the wild Gobi Desert: don’t forget to sample some airag, the Mongolian specialty drink of fermented mare’s milk. The last leg of your journey takes you past the Great Wall to Beijing, where you can watch the last minute preparations for the 2008 Olympics.

(Train information – www.seat61.com )

7. Camel Trek Across the Sahara (Sahara Desert, various countries)
All those pictures of camels wandering across seemingly endless stretches of sand dunes got you thirsty for adventure? No worries – camel treks are easily arranged from Egypt and Morocco (Libya for the braver souls). Get your fill of nomads, dunes, and oases as you embark on this epic adventure, which can range from one day to a few months. A word of caution: your butt will be so sore that you’ll probably end up walking instead of riding. Oh yeah, and camels love to fart.

8. Swim with an Elephant (Nepal)
Ever wondered what an elephant’s skin feels like? How about it’s gigantic, floppy ears? Ponder no further. Get up-and-close to Asian elephants in the jungles of Royal Chitwan National Park in Nepal. For just a few dollars, order an elephant to your hotel room door. Climb onto the elephant’s back, ride bareback into the hotel-side river, and enjoy a most unusual morning swim!

(Tours by local elephant owners in Sunauli, Royal Chitwan National Park)

9. Burning Man Festival (United States)
Where else can you ride flaming roller coasters, sip cold brews on a three-story party bus modified to look like an ancient Mayan ship, watch a few thousand (topless) women bicycle simultaneously, and witness hundreds of fire-dancers in the choreographed performance that precedes the burning of sixty-foot man – all in the middle of a flat, barren desert in Nevada? Only at Burning Man, the alternative festival that takes place the week before Labor Day each year. Spectators are discouraged, but participants are welcome. Check out the flicks on the website and you’ll be buying your ticket in no time.

(Official Burning Man website: www.burningman.com)

10. Volcano Boarding (Nicaragua)
So you’ve definitely heard of snowboarding, and you might’ve heard of sandboarding, but chances are that “volcano boarding” hasn’t made it onto your radar. This extreme sport involves riding a wooden board down the four-hundred-meter slope of an active volcano. Yeah, you heard us. Wondering about the safety factor of careening (at speeds up to sixty kilometers an hour) down sharp and prickly pumice shards? For protection, tour operators provide “funky orange prison suits” and “cool ‘science lab’ goggles,” but we’d recommend sliding down on your butt. Just leave that part out when you’re bragging to your friends.

(About $20 per person per ride, including round-trip transportation to the volcano, boards, suits, and goggles. http://www.bigfootadventure.com/ )

Article by Anna Wexler