Biosphere 2

Just outside the town of Oracle, Arizona, nestled between the seemingly endless plains of the Sonaran desert and the cactus-pocked foothills of Mount Lemmon, stands an enormous glass ziggurat: Biosphere 2.Built in the late '80s at the behest of an oil tycoon, the structure was intended to be a small-scale model of a self-contained ecosystem--hence the name--the earth itself is "Biosphere 1". Constructed with an airtight seal, Biosphere 2 was built to see if humans could sustain themselves in a c...