TMC Earth Day 5K at Biosphere 2 2027

The TMC Earth Day 5K at Biosphere 2 is a 5K run and walk held entirely within the Biosphere 2 grounds, located in the western foothills of the Catalina Mountains north of Tucson. The event is centered on Earth Day, and its location distinguishes it from a typical neighborhood 5K. Participants run through a facility designed to showcase entire ecosystems contained within a single structure and across a research campus. The route guides runners and walkers from desert environments to exhibits and areas representing a rain forest, an ocean reef, and savanna grasslands, all within a single event. Run Tucson organizes the race, applying its experience from producing 5Ks, 10Ks, half marathons, marathons, trail races, road races, and RRCA-certified coaching. The event accommodates both runners and walkers, with a primary appeal being the opportunity to combine a short race with a visit to one of Arizona’s most distinctive science facilities.