Colossal Du-Is it Tougher than You? January 5, 2013, 7:30 am start 5K, 12 mile, 2 mile Duathlon Presented by: Tagg Runing Events and AndRace.com A Beast of a season opener Multi-sport event: Run/Bike/Run Get your low gears ready to climb. We've matched one of the toughest 5k's in Southern Arizona with a hilly 12 mile bike course, and finishing with a 2 mile run. It all starts and finishes in breathtaking Colossal Cave Mountain Park. Pre-registration is required.