Today, again, the programme only features one pass, but it's a serious one, as the Col de l'Iséran is the highest genuine Alpine pass, at 2764 m. But Stage Five actually begins as Stage Four ended, riding on up the Arc Valley. As far as Bonneval-sur-Arc the valley only slopes gently upwards, so we have plenty of time to loosen out. The turn-off to the Col de Mont Cenis, in Lanslebourg, brings it home to us that the border with Italy is over there on the right, over that line of mountains. Then, in Bonneval, the tranquil uphill ride turns into a real climb, because the actual ascent to the Col de l'Iséran starts here. The highest genuine pass in the Alps - for the Cime de la Bonette in the Maritime Alps is, after all, not a real pass - takes us up to 2764 m. After around 50 kms of approach and ascent, there follows 50 kms of descent, down to Bourg-Saint-Maurice, where the stage ends. This is a real Mecca for climbers because, apart from the Iséran, two other passes begin here too, the Petit St. Bernard and the Cormet de Roselend, which is on our itinerary tomorrow. To summarise, then: up, down, and done. Variant: There is a rewarding optional loop to the Lac de Tignes. That would bring today up to 112 kms and 2200 m of climbing.