Various locations - 1958
1. Footage from AP's Movietone Archive of peloton riding at the 1958 Tour de France
2. Footage from AP's Movietone Archive of two riders at the 1958 Tour de France
3. Footage of solitary rider and motorbikes from AP's Movietone Archive of the 1958 Tour de France
4. Footage from AP's Movietone Archive of several riders descending at the 1958 Tour de France
Various locations - 1961
5. Aerial footage from AP's Movietone Archive of race ascending mountain pass at the 1961 Tour de France
6. Aerial footage from AP's Movietone Archive of race crossing mountain pass at the 1961 Tour de France
Various locations - 1975
7. Footage from AP's video archive of riders ascending mountain pass at the 1975 Tour de France
8. Footage from AP's video archive of riders ascending mountain pass at the 1975 Tour de France
9. Footage of solitary cyclist and mountain scenery from AP's video archive of the 1975 Tour de France
Saint-Lary-Soulan Portet pass, France - 25 July 2019
10. Still photo of Geraint Thomas in the race leader's yellow jersey at the 2018 Tour de France
Location not provided - 20 June 2019
11. SOUNDBITE (English) Tour de France champion Geraint Thomas, speaking in a June 20, 2019, Whatsapp message to AP:
"When you ride over 2,000 meters, you definitely feel the difference, compared to say 1,000 or lower. Basically, like, you just can't do the same powers that you do at sea level. It is just like a thinner sort of air, really, up there. You can just tell like when you're breathing, you're just not getting quite as much oxygen in the lungs as you normally would."
2018 - Location and exact date not available
12. Still photo of Geraint Thomas in the race leader's yellow jersey and other riders at the 2018 Tour de France
13. Still photo of Geraint Thomas in the race leader's yellow jersey at the 2018 Tour de France
Location not available - 1961
14. Footage from AP's Movietone Archive of rider racing up mountain pass at the 1961 Tour de France
15. Footage from AP's Movietone Archive of spectators around road sign indicating the Tourmalet pass in the Pyrenees at the 1961 Tour de France
Location not available - 2007
16. Still photo of pack of riders speeding down the Iseran pass in the French Alps at the 2007 Tour de France
2018 - Location and exact date not available
17. Still photo of Colombian rider Egan Bernal at the 2018 Tour de France
2019 - Location and exact date not available
18. Close up of Tour de France director Christian Prudhomme in AP interview on June 19, 2019
19. Medium of Tour de France director Christian Prudhomme in AP interview on June 19, 2019
20. SOUNDBITE (French/annotated translation in English) Tour de France director Christian Prudhomme in AP interview on June 19, 2019 "We know that riders can react differently above 2,000 meters. But most of us believe the Colombians won't be any less good at 2,000 meters and Bernal, obviously, is Colombian."
2018 - Location and exact date not available
21. Still photo of Colombian rider Egan Bernal, in white, and Geraint Thomas, wearing the overall race leader's yellow jersey, on the Alpe d'Huez climb in the French Alps at the 2018 Tour de France
Location not available - 1961
22. Footage from AP's Movietone Archive of the race on a mountain road at the 1961 Tour de France
23. Footage from AP's Movietone Archive of riders speeding through a tunnel on a mountain road at the 1961 Tour de France
24. Footage from AP's Movietone Archive of race vehicles speeding through a tunnel on a mountain road at the 1961 Tour de France
25. Footage from AP's Movietone Archive of rider climbing past spectators on a mountain road at the 1961 Tour de France
26. Footage from AP's Movietone Archive of lone rider in the fog on a mountain road at the 1961 Tour de France
At the Tour de France, the tough ascents riders must make through the Alps and Pyrenees mountains are always decisive in helping to weed out the winners from the also-rans.
But this year, they could have an even greater bearing than normal on the outcome of cycling's showcase race.
For the first time in the history of the 116-year-old cycling test of endurance, Tour de France organizers have peppered the route with three stages that finish on mountain climbs to above 2,000 meters, or 6,500 feet.
The thinning air at altitude will have a cascade of physiological repercussions on the riders' straining, tired bodies. They'll find it harder to breathe. They'll lose power. Their muscles will get sore faster.
Geraint Thomas, the 2018 Tour de France champion who will be seeking to defend his title at this year's race that starts July 6 in Belgium, says riding above 2,000 meters is especially trying.
"When you ride over 2,000 meters, you definitely feel the difference, compared to say 1,000 or lower," he told The Associated Press as he was training for this year's race.
"Basically, like, you just can't do the same powers that you do at sea level. It is just like a thinner sort of air, really, up there. You can just tell like when you're breathing, you're just not getting quite as much oxygen in the lungs as you normally would," he said.
Only the fittest and those most adapted to the mountains are likely to do well. The Tour de France director told The AP that he believes 22-year-old Colombian rider Egan Bernal might thrive on this year's mountainous route. Bernal is a teammate of Thomas' at Team INEOS.
"We know that riders can react differently above 2,000 meters," Tour director Christian Prudhomme told the AP in an interview looking ahead to the race. "But most of us believe the Colombians won't be any less good at 2,000 meters and Bernal, obviously, is Colombian."
But the punishing ascents, the thinning mountain air, the often dangerous snaking descents at speed and the expected heat of the French summer can all combine to also knock race favorites out of contention.
Indeed, the only thing that is ever certain about the Tour de France's climbs is that even the strongest riders are never guaranteed of getting through them unscathed.
