In 1991, eight people sealed themselves inside a glass world in the Arizona desert for two years, and the experiment nearly unravelled when the oxygen began disappearing from the air they were breathi

On 26 September 1991, eight people were sealed inside Biosphere 2, a three-acre enclosure of glass and steel near Oracle, Arizona. They stayed for two years. And the oxygen in their sealed atmosphere did fall, slowly and persistently, until it reached a level low enough to be a genuine medical problem and outside oxygen had […]