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Biosphere 2
Biosphere 2. The 'Biospherians' pose for the camera during the final construction phase of the Biosphere 2 project in 1990. Left to right are: Mark Nelson, Linda Leigh, Taber MacCallum, Abigail Alling, Mark Van Thillo, Sally Silverstone, Roy Walford and Jayne Poynter. The 3.1 acre air- and water-tight building became their home for two years. Biosphere 2 was designed to allow study of human survival in a sealed ecosystem. The costs of this controversial, $150 million project were met from private funds. The Biosphere 2 project building is at Oracle, Arizona. Bilde: Science Photo Library, NTB / CC BY-NC