Race organisers had acted boldly in making a double ascent of l’Alpe d’Huez the centre-piece of the hundredth Tour de France.
The riders, however, not to mention the estimated 500,000 people lining its infamous 21 bends, made it a gamble that paid off brilliantly.
And Christophe Riblon gave the host nation another reason for justifiable pride, producing a brilliant ride to catch and pass long-term leader, Tejay Van Garderen, almost within sight of the finish line.
For race leader, Chris Froome, penalised 20 seconds for taking on food after the feeding zones had closed, events on l’Alpe took a worrying turn.
The steeper the roads get, the stronger the 24-year-old Columbian climber, Nairo Quintana, becomes and the further the contest with Froome looks from being over.
Relive a magical day in the Tour de France through the lens of Stefano Sirotti in this gallery.