In the early 1990s, eight people tried to survive in a hermetically sealed glass structure filled with miniature forests, oceans and savannah.

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 a hot spring at Yellowstone National Park, a microbe does something that life shouldn’t be able to do: It breathes oxygen ...