The world's most amazing trail runs

Trofeo Kima, Italy: Running? Pah. This circuit through the Italian alps is more of an exercise in mountaineering. Clambering and crag hopping across a whopping 8,400m of ascents with the help of via ferrata (and your own wobbly legs), this is a pure test of toughness

Ultra Pirineu, Spain: This 100km of good old fashioned trail in northern Catalonia's Serra de Caldi mountains is one of the most demanding runs in the world. Lucky the view's not bad

Richtersveld Transfrontier Wildrun, South Africa: If hopping boulders and giving chase through 200km of remote desert wilderness is your idea of fun, this one's for you. It's a unique chance to explore the natural wonders of one part of the planet that's relatively untouched.

Run the Rut, USA: Exploding out of Big Sky, Montana (yep, those are some big skies), this vertical climb tracks the unused ski trails and pine forests on the edge of Yellowstone National Park. We always preferred scrabbling through scree to boarding through powder, anyway.

Matterhorn Ultraks, Switzerland: If the imposing shadow and sheer, colossal beauty of the Matterhorn doesn't pull you through this 17km alpine blast, we don't know what will. Maybe the hot tub back in Zermatt.

Grand to Grand, USA: When it comes to US trailblazing, it's hard to beat this race – traversing a whopping 274km, it takes in two of the grandest, dustiest, red rock monuments in America. Think epic southwest road trip, just without the car

Mourne Skyline MTR, Northern Ireland: the picturesque rolling mounds and sprawling Mourne Wall will do nothing to stop your legs aching when you've got 3,350m of ascents and nine peaks to climb. And they say the UK doesn't have testing mountains.