When the Tour director Christian Prudhomme was once asked what effect the decision to venture into the Pyrenees for the first time in 1910 had had on the race, he didn't beat around the bush.
"It was an incredible breakthrough," Prudhomme said, "almost as big as when it started in 1903. I've heard people say that [the film] Avatar was as big a development for cinema as when films started using sound. For the Tour, the Pyrenees gave the race its own 'third dimension'."
A century on, and out of what Prudhomme calls "respect for the Tour's roots," the Tour is hitting the Pyrenees big-time. Yesterday it had its first stage there, and a total of four – more than in at least a decade – will have been tackled by the time the Tour leaves the region on Thursday night.
Just to hammer the history lesson home, tomorrow there will be a repetition of the first ever stage to be held in these mountains. Just as in 1910 the riders will cross the Peyresourde, Aspin, Tourmalet – the most frequently used col in the Tour – and Col d'Aubisque. A second ascent of the Tourmalet, the 74th by the Tour, on Thursday will almost certainly decide the overall winner.
However, with so much hullabaloo about the centenary of the Pyrenees, and so many exploits surrounding them, it is deeply ironic that the mountains only started to be used by the Tour because of a barefaced lie.
When Henri Desgranges, the Tour's first director, sent his right-hand man Alphonse Steines to reconnoitre possible routes in early 1910, Steines set off in a car, complete with chauffeur.
Four kilometres from the top of the Tourmalet pass, however, the car's path was blocked by an impassable wall of snow. Ignoring his chauffeur's pleas that he should turn back, Steines got out and plodded off upwards. By midnight, with no sign of him on the other side, search parties were sent out.
Next morning, his teeth chattering and with his clothes supposedly in tatters, Steines appeared in the village of Bareges where he instantly sent a telegram to the Tour's Paris office: Tourmalet Crossed. Perfectly Usable. Excellent Road.
Thanks to his fib – or perhaps he was just being very tongue-in-cheek about it – later that year the riders set off at 3am on a 326km (204 miles) stage from Luchon to Bayonne. Despite the course being up and down dirt tracks rather than roads, riders were encouraged not to walk, with France's Gustave Garrigou earning a 100 franc bonus for staying on his bike throughout.
The stage winner, Octave Lapize, took a staggering 14 hours and 10 minutes to complete the course, but rather than his post-victory reaction it is his comments after reaching the summit of the final climb, the Aubisque, that made it into Tour history. When one reporter shouted at him what he thought of the Pyrenees as he pedalled past, Lapize yelled back "Murderers! You're murderers!"
A soundbite of that quality was like waving a red rag at a bull for the organisers, who promptly decided that the Pyrenees would have to become a regular feature, the only changeable element being whether they or the Alps are tackled first in the Tour.
With a spectacular if daunting collection of cols to choose from, tales of courageous breakaways, perilous descents and other two-wheeled heroics quickly grew, with Eugene Christophe's 1913 combination of racing and blacksmithing one of the most famous.
After breaking his bike on the descent of the Tourmalet, Christophe rushed to the village blacksmith but, as the rules banned any external assistance, he had to repair it himself. He took several hours to do so, and completed the stage – only to find he had been fined for using a local lad to work the bellows.
Over time, each climb has developed its own historical niche. The Peyresourde, for example, was the scene of Miguel Indurain's first ever spectacular ride in the mountains, when he drove so hard at the front of the pack in 1988 that his then leader Pedro Delgado had to tell him to slow down. "He cut the pack down to just a dozen riders he was riding so fast," Delgado recalls, "and when I asked him to ease up, he refused until I told him that if he continued he'd be the only rider left.
"That evening I told him he could win the Tour one day. Miguel looked at me as if I was crazy." The great Basque went on to win it five times, of course.
Other Pyrenean "highlights" have more comic elements. In 1950 the Aspin was the scene of a legendary duel between Jean Robic and Gino Bartali, in which neither could shake off the other. By the summit the Frenchman and the Italian were both so exhausted and riding so close together that they were virtually propping each other up. When they did collapse, like circus clowns they both lost balance and fell off.
Danger has an equally important, sometimes tragic, role to play in the lore and lure of the Pyrenees. The Portet d'Aspet, tackled today, was where the Italian Fabio Casartelli lost his life in 1995 on a descent. Other riders have been luckier in their confrontations with these mountains: coming off the Aubisque in 1950, the first ever Dutch leader of the Tour, a former black marketeer by the name of Wim Van Est, fell 70 metres into a ravine. When he was fished out, he was unharmed.
Inevitably the greatest of the Tour champions, Eddy Merckx, had a special relationship with the Tourmalet, the race's greatest Pyrenean climb. In 1969, riding his first ever Tour but already in yellow, the Belgian dropped all his challengers on the Tourmalet before catching and passing a team-mate, Adri Van Den Bosche, without so much as a look back.
Despite all his rivals working behind together, Merckx's final advantage was more than eight minutes: not so much a defeat as a rout. That year Merckx won everything in the Tour – six stages, the points classification, the King of the Mountains jersey and the overall.
Thirty years later, thanks to that breakaway, the Belgian got a velodrome named after him too – in Mourenx, the village where the stage finished, and where the legend of Eddy "The Cannibal" Merckx was born. Forty-one years on, the Pyrenees remain just as fertile terrain for more sporting heroes to be created.