Following Adventure Cycling's epic Great Divide Mountain Bike Route, the Great Divide Race (GDR) travels 2,490 miles of mostly unpaved road and trail, crisscrossing the Continental Divide 28 times. Truly a grassroots event, there is no entry fee, prize money, and little to no media coverage of the ride. In classic touring tradition, riders in the race are entirely self-supported, carrying everything they need — food, water, shelter, tools — on their bikes and backs, making the Great Divide Race not only the world's longest mountain bike race, but the most challenging cycling race in existence.

What follows are a series of pictures taken by Aaron Teasdale on the first day of the 2007 race.

To learn more about the Great Divide Race, click here. To learn more about Adventure Cycling's Great Divide Route, click here. To see the gallery from last year’s race, click here.