It’s not the most difficult nor does it always play the most important role in the Tour de France.

But the ascent to L’Alpe d’Huez (pronounced LALP-DWHEZ) is the most famous in the Tour de France. And it’s what the field will face Wednesday in stage 17 in the most difficult day of the race’s 95th edition and arguably among the most strenuous in race history.

The remaining 151 riders (from the starting field of 180 on July 5 in Brest) will pedal 210.5 kilometers (130.7 miles) from Embrun to L’Alpe d’Huez, the ski resort named after the River Huez.

The climb to L’Alpe d’Huez made its debut in 1952 with Fausto Coppi of Italy victorious, and it's marked a Tour de France stage finish 24 times.

But it was nearly a quarter century after Coppi's solo win when Dutchman Joop Zoetemelk jump-started the mountain’s wondrous reputation with his solo win. Zoetemelk’s teammates Hennie Kuiper, Peter Winnen, Steven Rooks and Gert-Jan Theunisse also won on the mountain, and it’s because of their successes, Dutch cycling fans camp on the mountain for days while waiting for the Tour to arrive.

Now more than a half-million spectators flock to the route to L'Alpe d'Huez each year to watch cycling at its best. And it’s party time before, during and after the cyclists arrive.

The ascent is about nine miles, features 21 switchbacks, has an average grade of 8.6 percent and has s
ections as steep as 11.2 percent.

Andy Hampsten won the L’Alpe d’Huez stage in 1992 and Lance Armstrong won it twice, in 2001 and in 2004. Armstrong’s latter win was negotiated as an individual time trial, a first for the famous mountain.

The finishing ascent is often the only hors categorie effort of the stage. But this year, it will provide the climax of a day that will include three hors categorie climbs.

The field will encounter Col du Galibier (pronounced GAHL-EBB-BEE-YAY) after about 50 miles and then Col de la Croix de Fer (pronounced COAL-DE-LA-CROY-DE-FUR) about 100 miles into the stage.

The Galibier has been part of the Tour since 1911 and it extends 18.3 miles at an average grade of 6.8 percent. Croix de Fer peaks at nearly 2,100 meters (6,779 feet) and some riders who nearly “cracked” on the Galibier may do so on the second mountain of the day.

In Tuesday’s second of three stages in the Alps, the top six riders began the two-mountain stage separated by only 50 seconds. At the end of the day, only the top four, led by race leader Frank Schleck (CSC-Saxo Bank) of Luxembourg, were within 50 seconds. Schleck retained his yellow jersey, but American Christian Vande Velde, who crashed in the final descent, dropped to sixth place, 3:15 behind.

The leaders will try to mark each other in stage 17, particularly on the final climb and after racing for more than six hours. But by the end of the day look for a larger gap at the top of the standings and few more dashed aspirations.