The Col de la Loze provided the highest point of this year's Tour de France, with Miguel Ángel López taking victory atop it and Primož Roglič tightening his grip on the yellow jersey.
It was the summit's first appearance in the French Grand Tour, rising to 2,304 metres above sea level, the first real altitude of this year's race.
But how did the riders find it? For the stage winner, he said that despite missing his family desperately back in Colombia, the high, harsh climb made him feel at home.
"These are climbs most similar to the ones I'm used to in Colombia. We kind of feel at home here on a climb that finishes above 2,000 metres of altitude. It's similar to the climb I do straight after leaving the house when training," López said after the finish.
With Jumbo-Visma having taken over the Ineos role of driving hard paces up climbs to thwart attacks from rivals, López says the difficulty of these climbs gives him opportunities to go on the offensive.
"I feel the race is changing a bit, I feel more at ease on these type of climbs, everything is turning out for the best," the Astana man continued. "I was hoping the style of racing would change in this last week because the teams would get a bit weaker and that would leave more room for attacking. I already had a go yesterday and then today was more my terrain."
As for Jumbo-Visma's yellow jersey, Primož Roglič, the Slovenian finished second, putting some more time into Tadej Pogačar (UAE Team Emirates) and extending his race lead.
"That was a really brutal climb in the last 3 or 4km, You can't compare it with anything. I'm glad it's behind us now."
In the final 3km the riders hit a 24 per cent ramp, followed by an 18 per cent slope 1,500m from the finish.
Before those last few kilometres, Adam Yates (Mitchelton-Scott) says the pace wasn't too high, as the GC riders steeling themselves for the gradients to come.
"Once we got into that last 7km section we actually went pretty easy for the first bit," Yates explained. "Everyone was kind of saying they didn't know what to expect, and then UAE started riding a hard pace. From then on it was kind of every man for themselves...I hung in there for as long as I could, so I can be happy with that."
It was tough for all the climbers, but spare a thought for the grupetto, will you?
Deceuninck - Quick-Step's Sam Bennett held on to his green jersey, finishing within the time limit, and one step closer to the Champs-Élysées.
"The first climb [the Col de la Madeleine] wasn't so bad, you could get a rhythm on it, but the last one the rhythm was always broken," Bennett said.
"For the grupetto it was okay because you could do an effort, recover, do an effort, recover, you could do it in steps. It was still a hard day but was manageable."
One final mountain day remains at the Tour de France, before the time trial up La Planche des Belles Filles.
Stage 18 features five categorised climbs, two first category ascents and then the HC Montèe du plateau de Glières before a rush to the finish line in La Roche-sur-Foron.
Thank you for reading 20 articles this month* Join now for unlimited access
Enjoy your first month for just £1 / $1 / €1
*Read 5 free articles per month without a subscription
Join now for unlimited access
Try first month for just £1 / $1 / €1