Don’t forget to look up,” says Miguel “Big Mig” Indurain, the great Spanish cycling campeón, to the massed ranks of nervously fidgeting riders. We all laugh because how could anyone forget to notice the stunning sweep of the Dolomites unfurling above the forested valley behind him. But we know he’s right. Because for the next eight hours or so, most of us will be lost in a world of self-inflicted torment as we pedal agonisingly up vertiginous hills, only to plummet with our hearts in our mouths down the other side, before doing it again, and again… We are in Italy’s picturesque South Tyrol to take part in the glorious Maratona dles Dolomites – Enel. It’s one of the hardest – and almost certainly the most scenic – one-day bike races in the world.

Mountains and bicycles aren’t natural bedfellows. Defying the thigh-burning power of gravity tends to spoil what could be a blissful union. But the annual Maratona manages to celebrate the jaw-dropping beauty of this brutal landscape by sending 8,000 Lycra-clad riders up and down seven of its most famous peaks. And, despite the fact that almost every single one of us will spend the day cursing the absurdity of cycling uphill, none of us would have it any other way. The spellbinding physical beauty of the Dolomites will take your breath away in more ways than you could imagine.

Mercifully, the event takes place on roads that are completely closed to traffic, so there is no danger from motorists trying to overtake you on narrow bends or even angrily shouting at you to “Stay in single file!”. For one day each year, these mountains are a cyclist’s paradise and we stream out across the full width of the tarmac in an endless colourful ribbon of carbon bikes and neon jerseys, all of us relishing our unchallenged occupancy of the high-altitude switchback roads.

This summer is the 35th anniversary of the race. It’s come a long way since the first edition in 1987, when just 166 piston-legged riders took part. Today, the Maratona has evolved into one of the highlights of the Italian cycling calendar. It’s broadcast live for six hours on national TV; numerous former champions take part and some of the sport’s most talented amateurs turn up to fly around the longest of the three routes in about half the time it takes the rest of us mortals to drag ourselves around it. But the magic of the event is the sense of accomplishment that everyone has: whether finishing in four and half hours or 10 and a half hours.

The action gets under way at 6.30am at the bottom of a tree-lined valley outside the town of La Valle. Despite the severity of the challenge that lies ahead, there’s almost a carnival atmosphere among the peloton, with hot-air balloons, low-flying helicopters, a brass band oompah-ing away and the race director, Michil Costa, sitting at the starting gate in traditional lederhosen on a penny-farthing. It’s only actually 5km from here to the finish in nearby Corvara, but the route takes a dramatic 138km, six-town detour instead.

If you look at a side profile of the Maratona’s route it looks like the serrated edge of a terrifying knife. There are no flat sections, it’s all up, up, up or down, down, down. The seven epic peaks along the way add up to more than 4,000m of vertical climbing, and the names of the legendary mountain passes that straddle the route almost sound like found poetry: Passo Campolongo; Pordoi; Sella; Gardena; Giau and Valparola. Of these the real monster is the Giau. It’s 10km at a lung-busting average of almost 10%. And after the relentless drag up its flanks, what do we do? Plummet down the other side at rollercoaster speeds of up to 50mph.

Despite the tears, sweat and swearing, there is much camaraderie. Riders of more than 70 nationalities take part and on the back of our jerseys, rather than race numbers, we have our names and a national flag. It makes for a great conversational opener for on-the-course chats – not that we had any spare puff. On one particular climb I tried to distract myself by counting the droplets of sweat as they fell from my chin on to the handlebars of my trusty Pinarello bicycle.

The Alta Badians are rightly proud of their mountain home and the Maratona is a showcase for the area, which has a rich heritage of distinctive dress, food and even language – many still speak the local language, Ladin. Volunteers and schoolchildren roll up their sleeves and cheerfully hand out pastries, sandwiches, cakes, energy drinks, Coke and even chunks of glistening parmesan and beer at the final feed station; people ring cowbells and blow horns. All along the way our ears resound to chants of “Bravo, Bravo, Bravo!” After one particularly perilous hairpin there was even a bodybuilder stripped to his poseur pouch flexing his oiled muscles. I wasn’t sure if I was hallucinating as I cycled warily passed him.

After 7 hours and 47 minutes in the saddle, the finishing straight finally arrived – and even that was uphill. Of the 8,044 entrants, I came in 1,687th. I’ve never been so relieved to get off my bike. Every part of me ached, but I was curiously sad that my epic ride had come to an end. After pizza (and chips and bread) and several celebratory beers with my finisher’s medal around my neck (it’s made of crushed hay – the organisers try to be as green as they can), we walked back to our chalet hotel. The sun was chasing golden shadows up the towering walls of the mountains behind us. It had been an amazing day, but looking up it was very clear what the real stars of the show had been.

The next Maratona dles Dolomites-Enel is on 2 July 2023 (maratona.it). Finishing in Corvara, there are plenty of bike-friendly hotels in Alta Badia’s six villages (altabadia.org). A useful tool to prepare for the challenge, three times Olympic cyclist Oli Beckingsale offers a training app, Kudo Coach (kudo.coach) which sets weekly goals and a training plan

Country classics

One-day races in the UK that make the most of the scenery

Dragon Ride
Perhaps the most famous sportive in Britain, the Dragon Ride crisscrosses the Brecon Beacons. It’s incredibly popular, incredibly hard and incredibly beautiful. There are four distances to choose from: 297km, 223km, 153km, 99km (dragonride.co.uk).

Étape Loch Ness
Not to be outdone by Wales, Scotland also has a race to match: the glorious 106km Étape Loch Ness. Starting and finishing in Inverness, the route takes in stunning scenery as it skirts Loch Ness. It also boasts very safe traffic-free roads (etapelochness.com).

The Cotswolds Classic
For rolling English hills, head to Stratford-upon-Avon. This ride offers three distances (118km, 82km, 59km), all of them leading you through medieval villages and past flower-filled meadows, churches and stately homes (ukcyclingevents.co.uk).

Mendips Lumps and Lakes Ride
Not all sportives take in thigh-burning climbs. If you prefer a flat-ish ride before winding your way through the Cheddar Gorge, then this Mendips ride is for you. Choose between the short 57km route or the full 120km ring. Stunning stuff (mendipsride.com).

Fred Whitton Challenge
‘The Fred’, as it is often referred to, is probably Britain’s hardest ride – and arguably its most beautiful. The 183km route around the Lake District takes you over Hardknott Pass and offers jaw-dropping views of the Eskdale Valley (fredwhittonchallenge.co.uk).

For information on great rides and events for all abilities in Europe and elsewhere, go to sportive.com

• This article was amended on 23 August 2022 to refer to Ladin as a language, not a dialect.