It's not what you think.
On Thursday I flew to Denver to shoot a bike race in Summit County, Colorado. The race starts and finishes in a teeny little town called Montezuma. It's a 24 hour endurance mountain bike race that has 13 separate, unmarked loops, crosses the Continental Divide 7 times, and includes two 14,000 foot peaks along with totally unpredictable weather. Montezuma itself is at an elevation of 10,400 feet. The event is truly sadistic. And some of the world's best athletes show up to get punished. It's absolutely the greatest race I've ever witnessed. There were 41 starters and about 30 people finished.
This photo is of Montezuma. It was taken with the EOS 10D and 15mm fisheye.