Biosphere 2 is located about 30 miles north of Tucson Arizona. It was built in the late 1980's and was designed as an air tight replica of Earth's evnironment (biosphere 1).

Some of the early designers and managers were interested in space travel and the possibility of colonizing the Moon or Mars. By building Biosphere 2 and sealing people inside, they hoped to learn what problems would arise from living in a closed system. So it was that in 1991, a colony of 8 people set about to live inside Biosphere 2 for two years.

Biosphere 2 is now used to study the affects of climate change. It is no longer maintained as a completely sealed environment.