The Biosphere 2 is an Earth systems science research facility conducting live research, now owned by the University of Arizona. It is a 3-acre structure originally built to explore the use of closed biospheres for space colonization and built to be an artificial, materially closed, ecological system. Biosphere 2 is open daily to 4 PM, costs $20 for an adult and is located at mile post 96.5 on Highway 77 north of Tucson.