PITTSBURGH, Pennsylvania – Most people would call The Dirty Dozen a grueling bicycle race. Hardcore cyclists in Pittsburgh call it a great way to burn off Thanksgiving dinner.

Every year since 1983 bike nuts have subjected themselves to a 50-mile ride that hits the 13 steepest climbs in a city not known for being particularly flat. Conquering that many hills is no easy feat, but to make it just a little tougher the route includes Canton Avenue, which has been called the steepest road in the world.

Canton Avenue takes no prisoners. It quickly and mercilessly punishes the weak and the stupid. This cobblestone beast has a 37 percent grade. It's a bitch to climb under the best of circumstances, much less after tackling eight other hills in 30 miles. The rest of the course is no piece of cake, mind you. It crosses rivers and valleys while also forcing riders to navigate holiday traffic.

Almost 200 riders turned out this year, and most of them conquered all the climbs. They're a dedicated bunch, and many of those who falter halfway up simply coast to the bottom and try again. The goal for most riders is to finish, not to win, and some of them need seven hours to do it. If it matters, this year's winners were Steve Cummings and Betsy Shogren, both of whom have won before.

Photos: Jason Kambitsis / Wired.com