The USA Pro Challenge bike race brings the best racers in the world to Colorado. While the winner will be a happening in Colorado, for many of the racers, with the elevation, grueling climbs, and thin air, Colorado will happen to them.

None of these folks are any stranger to riding over peaks and passes, but still, the thinner air will take its toll on some of the participants.

That's why the Loveland to Estes Park and back loop through Thompson Canyon may be the most crucial location along Stage 6. Click for Stage 6 Map and Info.

Other sections of the course should leave a pretty level playing field. They'll average between 4,700 and 5,000 feet above sea level. Higher than much of the country, but nothing to lose your breath over.

When they get to the climb through Thompson Canyon, it will show which riders were really ready for it.

Then, on the way down, we'll see who has the stability and confidence to fly through the dozens of turns that switch back and forth more than a politician in hot water . We'll see riders almost sideways as they bank through the curves. A lot of time can be made up without expending too much energy, unlike on the way up.

If you want to watch this exciting part of Stage 6, click here to see the best places to view the race.