Le Tour de France. Arguably cycling's biggest and greatest event.
Cyclists from all corners of the world take part in the event that sees you traverse many, many miles across quite a few days.
Just passed is stage 16. The sixteenth day of cycling for all involved.
You've got to be staggeringly fit to even make it through the course, let alone compete at a professional level.
Can you imagine the toll this takes on your legs? It's got to hurt.
Now, you can feel the pain of the cyclists thanks to Instagram and Polish cyclist Pawel Poljanjski, who has taken to the social media platform to show to the world just what effect the strain of Le Tour de France is having on his legs.
Be warned - it's not a pretty sight.
He says alongside the photo: "After sixteen stages I think my legs look little tired." Yeah.
For all his obvious effort, Poljanski is currently sitting in 75th place - a position he's hoping to improve upon.
As expected, the photo went viral, picking up over 16,000 likes and 1,600 comments in the process.
Summing up what we're all thinking was user emilymcgrath_: "This has to be a joke. Jesusssss."
It doesn't get any easier for Poljanski, either. Stage 17 features two grueling climbs, including the Col du Galibier, which is a daunting 2,642 metres.
With current standings, Chris Froome is just out in front, with a lead of 18 seconds over the chasing pack, led by Fabio Aru.
If Froome can survive Stage 17 still at the top of the leaderboard, then he will win his fourth yellow jersey in the last five years.
Froome has admitted that the next two days will be the biggest this year: “The next two days will be the biggest of this year's race."
Indeed, Froome will need to put everything he has into Stage 17 if he is to stand a good chance of winning Le Tour de France altogether.
His slog through the Alps will need to be practically perfect in every way.
To be fair, however, Froome's race this year has been perfect in all but 400 yards. He looks in imperious form at the moment.
As for poor old Poljanski, he'll need to put those tortured legs to work again across the harsh climbs of the Alps.