VERONICA MCGREGOR, CNN PRODUCER: Four men and four women were going to be enclosed inside this giant structure -- It looked like a giant terrarium -- in the Arizona desert, and it was called Biosphere II. It was a group of people who were hoping that this would be a prototype for colonizing other planets, in particular Mars. The rest of the scientific community did not look at this group as being a scientific group at all. Days before they went in and locked themselves in, I got to go inside and tour the Biosphere. You had rain forest, they had a small ocean with a coral reef, they had the mangroves, they had a desert area, they had an agricultural area, they had animals that they were raising for food. Their hopes were to stay in there for two years without ever coming outside. It didn't take long for something to go wrong. Within three months, they had to pump new air into the biosphere because the oxygen levels were so depleted. So after that, the experiment was not looked on very favorably. They came out two years later, again to great fanfare, and within a year or so after that, there was a big rift between the group. It looked the entire experiment was going to just be abandoned. But a few years ago, Columbia University actually took over Biosphere II, and they run it, and they use it for ecology experiments, and they are hoping to actually get some science out of it, and they have.
CNN 20: Biosphere II Experiment Begins, September 25, 1991