In the modern era, finding a true off-the-beaten-track adventure can be difficult. Mark MacKenzie uncovers some to test the toughest

Comparing the relative dangers of proposed expeditions is the adventurer's equivalent of comparing City bonuses; bigger is better and sheer bravado is best. The less likely you are to return from distant shores with all your limbs, the greater the credibility of the challenge ahead. Should you wish to enhance your reputation beyond measure, best not to return at all.

Obscure locations can also build Brownie points, of course, but with pretty much anywhere just a Google away, finding that USP is no longer a question of sticking a pin in one of the less annotated pages of the atlas. Where once the summiting of mountains or polar treks were only for specialists, today they are open to allcomers. Mount Everest is a good example. Weather and fitness permitting, tours of duty on the iconic peak are available to anyone who can stump up £30,000 (roughly the cost of joining an expedition).

Another example of the "classic epic" is the Marathon des Sables. Last year, close to 600 of the 700 starters finished the six-day, 150 mile-plus slog through the Sahara desert, a sign of the improved understanding of the demands of the event, first run in 1986.

All of which is rather bad news for those who like their adventure flavoured with a pinch of exotica. So if you want a suitably demanding name to drop, here we offer a few suggestions:

Life in the freezer

A challenge of the 'in-for-a-penny' variety. While countless events proclaim themselves the toughest of their kind, the fifth Yukon Arctic Ultra race is hard to top. In this "multisport" event, competitors must first nominate their race distance (26, 100, 300 or 460 miles) before choosing their mode of transport. When the small army of runners, cross-country skiers, mountain bikers and skijorers (skiers pulled by dogs) leave the town of Whitehorse in the Yukon Territory in February, Canada's most inhospitable winter region will doubtless do its worst.

With temperatures predicted to bottom out at around -30C, the luckiest athletes are the marathon runners, the best of whom have, in recent years, found themselves back in front of the fire just four hours after the starting gun has fired. Those racing in the 460-mile category, on the other hand, will take a maximum of three weeks (yes, weeks) to negotiate their frozen tundra course. Mandatory kit therefore includes a satellite phone, GPS system, crampons and an avalanche shovel. Unpredictable terrain and frozen river crossings are just a few of the obstacles to be overcome, with checkpoints sporting such welcoming names as Dog Grave Lake.

Last year, Britain fielded 23 competitors, more than any other nation. One, Jon-athan Lucas, even succeeded in winning the 100-mile skijoring category.

The most famous Arctic race of all is the Iditarod, the 1,150-mile dog sledding monster that runs from Anchorage to Nome, in which legendary mushers fight tooth and claw for prize money of $720,000 (£365,000). Organisers of the Yukon Ultra are rather blunt on the subject of cash: "There will be no purse." So just for the fun of it, then.

Channel hopping

For Brits, ocean swimming tends to involve basting oneself in goose fat on a Dover beach at dawn before heading into the chaotic shipping lanes that crisscross the English Channel, a route to Calais first established by Captain Matthew Webb in 1875. Although only half as wide as its English counterpart, the Rottnest Channel is an ocean swim that presents a rather different set of challenges. The 19.2km stretch of water separates Rottnest Island from Perth, in Western Australia. Like the English Channel, it can get bloody cold; unlike the English Channel, it is patrol-led by Great White Sharks. At least one swimmer has been killed in the area.

The first person to swim it was Gerd von Dincklage-Schulenburg in 1956. He completed the swim in 9hr 45min, and his feat caught the imagination of a local newspaper editor. Later that year the first race was held, won, appropriately enough, by a Mr Seaborn.

Known to aficionados as "the Rotto", the modern race attracts around 2,500 entries (places for 2007 are still available), the first wave of which sets off from Perth's Cottesloe beach at dawn. Once at sea, competitors swim either solo or in teams, and must contend with notorious rip currents plus, in between the sharks, squadrons of stingrays.

Almost as dangerous as the marine life are the support boats. With each entry requiring a designated pilot vessel, swimmers must pick their way through a huge flotilla of craft. The effect, some swimmers report, is like participating in the Normandy landings having swum there in the first place.

Off-road trip

For physical punishment on two wheels, not much tops the Tour de France (even with chemical assistance). But for off-road action, La Ruta de los Conquistadores, a mountain- bike race held every Nov-ember in the jungles of Costa Rica, is widely acknowledged as one of the most brutal in the world.

The race is the brainchild of Roman Urbina, a former triathlete and road racer who in 1993 brought 30 fellow bikers to the island in an attempt to recreate the Pacific-to-Caribbean coastal trail first ridden - on horseback - by the invading Spanish army in the 16th century. While it took the conquistadors two decades to establish the route, today's cyclists must negotiate the 200-plus miles in just four days. Most ride La Ruta unsupported, and the terrain includes an ascent of the rainforest-clad, 3,432m peak of Volcan Irazu, meaning "point of thunder".

Conditions under-wheel can get decidedly ashen, while lower down the rainy season reduces unsealed stretches of road to a bog for up to 20 miles at a time. Participants can spend much of their time carrying their bikes, and in temperatures of 40C with relative humidity as high as 90 per cent, excellent aerobic fitness is needed. Two years ago, a third of competitors dropped out on day one, and organisers "strongly advise that you compete on a mechanically flawless bike".

Rapid reactions

This year the Ocoee Whitewater Centre near Ducktown, Tennessee, celebrates its 10th anniversary. It was built to host the canoeing events of the 1996 Olympic Games, and its cost, $12m (£6.1m), left organisers with some explaining to do.

This stretch of the Ocoee provides one of world's more gruelling whitewater challenges. Enthusiasts have been organising white-water competitions on the Ocoee's lower reaches for the best part of 30 years, but when looking for a venue that would accommodate Olympic-sized crowds, developers from the US Forest Service chose a portion of the upper river that, thanks to a hydroelectric project, had been more or less dry since 1940. So to spice things up, planners brought in 60,000 tons of rock and narrowed the river channel by half.

The result was a slalom course 1,300ft long by just 50ft wide, plummeting over huge ledges and disappear-ing into holes deeper than any seen before in inter-national competition. When the course was trialled by a World Cup kayaking event a year before the Games, safety crews had to rescue 25 competitors who had misjudged rapids. Among them were some of the best paddlers in the world and most told of how, by the time they reached Humongous, the course's final rapid, they were so tired that they were simply overwhelmed.

Today, the size of the rapids is carefully controlled by a series of dams. Release schedules are available online, but a safer option is hooking up with one of the 24 rafting outfits offering to guide you down "America's Olympic river". Access for rafters is limited (just 34 days this year), and while altering the flow of any major river channel is usually accompanied by controversy, the Ocoee is an environmental success story. Decades of copper mining rendered this part of the Upper Ocoee biologically dead but today, riverine wildlife has returned.


The Yukon Arctic Ultra runs from 11-24 February. Details:

The 2007 Rottnest Channel Swim will be held on 17 February. For race and entry information: rottnest The 2007 La Ruta de los Conquistadores takes place from 14-17 November. More information:

For details of the Ocoee Whitewater Centre, contact the US Forest Service: 001 423 496 0100;