The Lacets de Montvernier: Eighteen Hairpins Built by Hand

Required Activities

• Ride or walk the 18 hairpins from Pontamafrey on the Arc up to Montvernier, counting them as you go, and work out what the road is doing: 3,350 m of tarmac to cover 700 m as the crow flies, four metres wide through the bends at 7.56 per cent, touching 10 per cent for one 53 m stretch

• Keep going to the top of the cliff and find the chapelle de la Balme standing at the roadside where the hairpins end, then carry on to Montvernier and Montpascal, the villages the road was built to reach

• From the top, look back down the stacked hairpins and line up the view against the photograph of this road that outsold every other at the Brussels world's fair of 1958 and then illustrated French school geography books for some fifty years

• Follow the line Boniface Bochet staked out and work out where the first contractor gave up after the lowest bends — everything above that was cut by hand by 36 men in the eleven months to April 1933, with only a lorry bringing cement from Chambéry and the sand sifted out of the Arc running below you

• Climb it as the Tour does, a second-category ascent of 3.4 km at 8.2 per cent, and remember what happened the first time it came here, on 23 July 2015: the road was judged so narrow that spectators were banned from the entire climb