Stretching 4,250km from Mexico to Canada, the Pacific Crest Trail is an incredible long-distance route which passes through 25 national forests, seven national parks and three West Coast states (California, Oregon and Washington). It takes you from breathtaking expanses of Californian desert through to the glaciated areas of Sierra Nevada, the remote foresty in Oregon and finally onto the highlight of the trail, Washington's Columbia Gorge and the rugged North Cascades.

Timothy Olson currently holds the speed record for a continuous hike of the PCT, which stands at an incredible 51 days, 16 hours and 55 minutes.

Other long-distance thru-hikes in North America include the Continental Divide Trail (5,000km), from Mexico to Canada via Montana, Idaho, Wyoming, Colorado and New Mexico, and the Great Divide Trail (1,200km), from Waterton Lakes National Park to Kalkwa Provincial Park, across the Canadian Rockies.

If the Three Peaks Challenge isn’t tough enough for you (summiting Britain’s three highest mountains, Ben Nevis, Snowdon and Scafell Pike in 24 hours), you can attempt to the Welsh 3000s: 15 mountains over 3,000ft including the Glyders, the Carneddau and Snowdon and Crib Goch, over 36km in 24 hours. This is a demanding mountain route (with Crib Goch being particularly exposed) which should ideally be attempted in late June, when you can make the most of daylight hours.

A more demanding alternative to the Welsh 3000s is the Lake District 3000s: 70km of hilly terrain over Skiddaw, Scafell, Scafell Pike and Helvellyn, not to mention a spectacular scramble along Striding Edge.

This compelling, 65km route is a six-day hike through the Cradle Mountain-Lake St Clair National Park, which is part of the vast and remote Tasmanian Wilderness World Heritage Area. En route, from Cradle Mountain to Lake St Clair, you summit Mount Ossa (5,305ft), Tasmania’s tallest peak, and pass through a plethora of environments, including moorlands and rainforests.

The weather can be notoriously unpredictable on the trail, which includes unannounced blizzards even in the summertime, so hypothermia can be as much of a risk as heat exhaustion and dehydration with poor preparation; the Tasmania Park and Wildlife Service recommends hiking from December to April.

By definition, a Munro is a separate mountain (not a subsidiary top) in Scotland which stands at 3,000ft or above; Scotland has a grand total of 282 Munros, not to mention 272 subsidiary Tops, which sprawl across the Highlands, predominantly in the Cairngorms, Glencoe, Loch Lomond and the Trossachs, and the west coast isles, including the Cuillin on the Isle of Skye.

For many peak-baggers, becoming a ‘Munroist’ (topping every single Munro) can take a lifetime; completing a continuous, self-propelled round of the Munros, however, is a different challenge entirely.

Long-distance trekker, BMC Ambassador and The Great Outdoors Gear Editor Chris Townsend was the first to complete a continuous round of the Munros and Tops on foot in 1996, which involved 2,830km of distance and 175,000m of ascent. Which route you pick is your choice, however it has been estimated that the most efficient for the continuous round is around 2,500km. In winter, the challenge, naturally, is even stiffer.