8 people entered a sealed glass world believing they could survive for two years

Deep in the Arizona desert near Oracle sits one of the strangest experiments ever built, a sealed, 3.14-acre glass and steel enclosure called Biosphere 2. Constructed between 1987 and 1991 at a cost of roughly $150 million, funded largely by Texas billionaire Edward Bass, it was designed to test whether humans could live inside a fully self-sustaining artificial ecosystem, complete with its own ocean, rainforest, desert, savannah and farmland. On 26 September 1991, four men and four women, known as biospherians, sealed themselves inside for what was meant to be a two-year mission. What followed became one of the most closely watched, and ultimately most controversial, science experiments of the decade.Why Biosphere 2 was built in the first placeThe facility took its name from the idea that Earth itself is Biosphere 1, and this artificial version was meant to model it in miniature. According to reporting on the University of Arizona's official description of the project, the enclosure was built as a materially closed ecological system, meaning almost nothing was meant to pass between the inside and outside world except sunlight. Beyond its scientific goals, the project was also fram...