Early on Sunday, as most of the south of France is beginning its post‑lunch siesta, the 181 cyclists remaining in the Tour de France peloton will crest a rise somewhere in the Drôme region and they will catch sight of Mont Ventoux to the south of them. It is hard to miss the Ventoux. It rears up in a solitary cone, its summit pale white whatever the temperature. It is easy to confuse that whiteness with the last snow of winter, but the white is actually something more intimidating: the moonscape of bare rocks that covers the summit.

The Ventoux will loom over the peloton as they ride southwards, then turn eastwards to travel along its southern foothills before hitting the first slopes in the town of Carpentras. Making the Tour field ride halfway around the mountain before they actually go up it seems a particularly sadistic trick. For several hours, the mountain will be sitting up there, mocking them, as if to say: "You have to come up here. There is no escape." It is equally cruel to put the Ventoux at the finish of the 2013 Tour's longest stage, 242.5km.

The philosopher Roland Barthes waxed lyrical about the mountain in his essay The Tour de France as epic. His case was that the Ventoux is different from almost all the Tour's other great climbs – even the most awe-inspiring passes such as the Galibier, the Iseran, the Bonette-Restefond and the Tourmalet – because whereas these are all cols, passages between two mountains or more, the Ventoux is a summit in its own right.

The cyclists climb to the very top and can go no higher. The only Tour climb that is comparable is the smaller but steeper Puy de Dôme in the Auvergne, but that has not been included in the route since 1988, and is unlikely to feature again due to the construction of a light railway up the road to the summit.

The Ventoux is an intimidating place. At the top, as the riders approach the monument to Tom Simpson – whose death on the mountain in 1967 forged its fearsome reputation – the whole of Provence is far below. The weather changes rapidly. The winds can be so strong on the summit that there are – admittedly rare – instances of people dying after being hit by windblown stones; it has claimed lives in snowstorms, flash floods, and thunderstorms.

It has its own climate, its own ecosystems – Alpine amid the lavender fields of the Midi – and some would say, a personality of its own: the haunt of wolves, witches and, some said, the gateway to the underworld. In the days before he was hunted down by the Furies of the United States Anti‑Doping Agency, Lance Armstrong felt the mountain had something against him: "Ventoux doesn't like Lance," he muttered, echoing the words of the Swiss Ferdi Kübler in 1955: "Ventoux has killed Ferdi."

Like many other cyclists, this reporter has ridden up Mont Ventoux, and, like many British bike riders, in search of Tom Simpson. I rode up the mountain 10 years ago while researching his biography, and once I turned left at the Saint-Estève corner to ride on to the mountain proper, it became crystal clear to me why its demands are outside the norm. To start with, the Ventoux has barely any hairpins. The road winds a little through the oak woods at the base, but it is basically going up the mountain. On a hairpinned climb, there is a regular change in the rhythm as you go upwards, but the Ventoux is unremittingly steep.

That's just the start. At the top of the treeline, you swing to the left past the slightly tacky cafe at Chalet Renard, past the ski-lifts (the skiing here is not reliable enough to make it truly worthwhile) and out on to the moonscape. Initially, you curve in and out of great bowls in the mountainside, which draw in the sun's heat in summer like massive ovens, before finally cutting across the bare slopes past the Simpson memorial to the observatory. The Stone Sahara, the former Tour organiser Jacques Goddet called it.

The Ventoux was a relatively early inclusion in the Tour's list of summit finishes, in 1958, after the Puy de Dôme and l'Alpe d'Huez, and it already had a reputation. In 1955, the Breton Jean Mallejac collapsed and came close to death in an incident that foreshadowed Simpson's death 12 years later. Lest we forget, Simpson was the leader of the Great Britain team that year, the closest British cycling had to a celebrity before the arrival of Sir Chris Hoy and Sir Bradley Wiggins, and his death came just as the sport was becoming aware of its massive doping problem.

Of all the Ventoux stories, Simpson's has marked the sport most, partly because of the immense personality of "Major Tom" – most British cyclists of a certain age can remember precisely where they were when the news came over the radio that he had collapsed – partly because, as the fight against doping has intensified, his death looks like the sport's ultimate morality tale. He sums up the essential ambiguity of professional cycling: a champion can be charismatic and well liked but still be a doper. The Ventoux – Tommy's Tump, as I like to think of it – is a reminder, from well before the Armstrong era, that drug takers are real people with dreams, hopes, loves and quirks,dreams and hopes as well as lies.

It is not just tragedy that has marked the Tour's history here. In 1994, the tallest, heaviest cyclist in the race, an Italian obscurity named Eros Poli, went on a solo break, gained many minutes before he got to the mountain, led the race over it – his advantage melting like an ice cream in the Provençal sun – and hung on to win the stage. It was a farcical moment, but evidence that even the most unlikely climbers can master the mountain. Along with the deaths and the defeats, this is a fable the Tourmen should keep in their minds on Sunday.