Biosphere 2, a complex designed to simulate Earth's multiple ecosystems, gleams in the Arizona sunset. A team of "biospherians" was sealed the complex on September 26, 1991, to start a two-year mission. The goal was to life off the food and other products generated inside Biosphere 2. One extended goal was to see if people could live in a habitat on another planet, completely cut off from the outside world. The complex includes an ocean, desert, savannah, and other ecosystems. Although the initial experiment wasn't fully successful, Biosphere 2 is still in operation today, conducting other ecological experiments. [Johndedios/Wikipedia]