The Ouray 100 starts and finishes at Fellin Park, only yards from the hot springs.  With over 40k feet of elevation gain, this is one of the most difficult 100 milers in the world.  The route includes:  Camp Bird Road, Silver Basin, Imogene Pass Road, Chicago Tunnel, Fort Peabody, Ptarmigan Lake, Richmond Trail, Ironton, Corkscrew Gulch, Gray Copper Trail, Weehawken Trail/Alpine Mine Overlook, Hayden Trail/Crystal Lake, Old Twin Peaks Trail, Silvershield Trail, Perimeter Trail/Lower Cascade Trail, Chief Ouray Mine Trail, and Old Horsethief Trail/Bridge of Heaven.