SANTA CATALINA MOUNTAINS, ARIZONA - At the base of the mountains is a complex of glass pyramids and geodesic domes held up by steel space framing. The three-acre complex currently owned by the University of Arizona is known as Biosphere 2. Decades ago, the complex was sealed shut to protect the miniature rain forest, a mangrove, a desert, and a coral reef from the outside world. The environment inside Biosphere 2 was all man-made. 

The project was financed by Ed Bass which reached up to $200 million in cost from 1985 to 2007. Biosphere 2 was put up with the goal to demonstrate an enclosed ecological system, pushing for the possibility to support human life outside Earth.

The domes and pyramids were made of steel tubing, steel frames, and high-performance glass which were custom designed mad made by Pearce Structures Inc. all openings were designed to be air-tight with a low leak rate of 10% per year. The extremely low air exchange allows for the tracking of subtle changes over time.

A constant volume of air was needed in Biosphere 2. However, the air would expand during the day and contracted at night. To achieve a constant volume, large diaphragms were installed in the domes. Another requirement is a regulated temperature which was met by the use of sophisticated systems because opening windows were not allowed. The project also has an energy center, that included backup generators, natural gas, water cooling towers, and ammonia chillers, that provided to cool down and heat water.

Biosphere 2 endured two failed attempts or experiments. The first was from 1991 to 1993 and the second one was from March 1994 to September of the same year. Both experiments failed because of problems including low amounts of food and oxygen, some animals and plants died off, tensions within team members or the resident crew, over management, and some controversies.

Even though both attempts failed, the data collected became a reference for other experiments and studies. In a published journal, studies included topics on different ecosystems in a carbon dioxide rich environment. Although there is a lot of material to use from the data collected, scientists and researchers are saddened that a huge bulk of the data was not archived and was instead lost and was never analyzed.

The ambitious project, Biosphere 2 was named as such because Earth is said to be the primary biosphere. At present, Biosphere 2 is open to the public, all 40 acres of it.