Semnoz (Cret de Chatillon) from Annecy
Semnoz/Cret de Chatillon dominates the skyline of the west shore of Lake Annecy in the Haute Savoie.
The climb starts almost immediately at the roundabout as you turn off from the D1508 leaving the town to the south. The road rises relentlessly through forest up a series of switchbacks for 5km before 3km of respite.
The remaining 9km seem never-ending, with the gradient rarely dropping below 9%. The views over Lake Annecy from the top almost make the suffering worthwhile!
The Tour de France climbed to a summit finish on Semnoz as recently as 2013, with the Colombian Movistar rider Nairo Quintana riding to victory.
Height at start: 448m
Height at finish: 1660m
Average gradient: 7.0%
Maximum gradient: 11.1%