At the time, they and their six teammates were sealed inside Biosphere 2, a 91-foot-tall, 3.14-acre experimental complex outside Tucson, Arizona.

Inside Biosphere 2, five "wilderness" zones — rainforest, ocean, savanna, marsh, and desert — emulated Earth's ecosystems. They helped scrub carbon dioxide from the air and generated oxygen.

TUCSON, Ariz. — A four-person crew will soon be locked inside a pressurized habitat at the University of Arizona's Biosphere 2, marking the first time such a mission has been conducted at the ...

TUCSON, Ariz. — A four-person crew will soon be locked inside a pressurized habitat at the University of Arizona's Biosphere 2, marking the first time such a mission has been conducted at the ...

TUCSON, Ariz. — A four-person crew will soon be locked inside a pressurized habitat at the University of Arizona's Biosphere 2, marking the first time such a mission has been conducted at the ...

TUCSON, Ariz. — A four-person crew will soon be locked inside a pressurized habitat at the University of Arizona's Biosphere 2, marking the first time such a mission has been conducted at the ...

Today in history, In 1991, four men and four women began a two-year stay inside a sealed-off structure in Oracle, Ariz., called Biosphere 2.

Biosphere 2 is 3.14 acres of science. Inside, human-made ecosystems are dedicated to helping us understand the future of our planet. A world within walls, where habitats grow and research thrives ...

TUCSON, Ariz. — A four-person crew will soon be locked inside a pressurized habitat at the University of Arizona's Biosphere 2, marking the first time such a mission has been conducted at the ...