Inside Biosphere 2's giant glass pyramid, tropical trees stretch 80 feet above the forest floor. Crazy ants, so named because of their erratic movements, scurry below.

Inside Biosphere 2's giant glass pyramid, tropical trees stretch 80 feet above the forest floor. Crazy ants, so named because of their erratic movements, scurry below.

Biosphere 2 lives on as a successful research site 30 years after eight people emerged from the experiment in the Arizona desert. (AP Photo/Ross D. Franklin) ...

Three decades after the original experiment, Biosphere 2 is still doing research that's the first of its kind. "There's no place where you can test on a large scale the response of complex ecosystems.

Biosphere 2, at 32540 S. Biosphere Road in Oracle, Arizona, is open every day (except Thanksgiving and Christmas) from 9 a.m. to 4 p.m. For more information, go to biosphere2.org.

Biosphere 2 project began in 1984, led by John Allen who called it “The Human Experiment.” The project sent eight explorers, or “biospherians,” to live in a sealed ecosystem for two years.

Inside Biosphere 2's giant glass pyramid, tropical trees stretch 80 feet above the forest floor. Crazy ants, so named because of their erratic movements, scurry below.

In early October, Biosphere 2 will receive endangered Quitobaquito pupfish to introduce into its habitat. The fish hail from Arizona's Quitobaquito Springs by the U.S.-Mexico border, where water ...

Inside Biosphere 2's giant glass pyramid, tropical trees stretch 80 feet above the forest floor. Crazy ants, so named because of their erratic movements, scurry below.