11:23 01 August 2013
In the late 1980s, in a patch of desert north of Tucson, Arizona, a group of environmentalists built a self-contained miniature world under glass which became home to researchers for a two-year experiment. Called Biosphere 2, it was designed to serve as a trial Mars colony and to enable the researchers to study ecosystems in their entirety. Plants and animals from around the globe were brought in to populate six different biomes, which still exist today. Tiffany O'Callaghan gives us a tour of the site – now open to visitors – which is still being used to gain insight into the original biosphere, Earth.
Read more: "Reality bites: the lessons of Biosphere 2"
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When planning Biosphere 2, engineers realised that large temperature swings from day to evening would alter the air pressure inside, and that this could crack the glass enclosure. To cope with the problem, they created two large "lungs" with vast rubber bladders that expand and contract with the changing air pressure.
(Image: David Kadlubowski/Corbis)
