With almost 15,000 feet of climbing over three hors categorie mountains, stage 17 is, on paper, the toughest of the Tour. It starts in Embrun, which also saw the start of stage 15, this time heading north through Briançon (42km) and on to the infamous Galibier, Croix-de-Fer and L’Alpe d’Huez that are among the most daunting climbs in the Alps. This stage could well decide the final outcome of the race because the riders will have been in the saddle six hours before coming to final ascent. The 13.3km, 21-turn climb to the finish at L’Alpe d’Huez (population 1,700) is a classic, averaging 8.6 percent, with the second kilometer the steepest at 11.2 percent.