Twenty years after Biosphere 2 broke ground near Oracle, the one-of-a-kind terrarium and its surrounding land have been sold for $50 million.

Gray wolves were reintroduced in Yellowstone National Park in 1995 to help control the numbers of elk that were eating young trees, and it is finally paying off for quaking aspen.

In the midst of climate change, awareness of humanity’s negative impact on the planet has grown, making the idea of moving to another planet more appealing. This led to the concept of Biosphere ...

Biosphere 2's ocean ecosystem contains 700,000 gallons of sea water brought in from the California coast — more than an typical Olympic-size swimming pool.

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.

The venture, privately funded to start, is now run by the University of Arizona. And today, scientists there are quietly plugging away at research they hope will help us all adapt to the Biosphere 1 — ...

Biosphere 2's ocean ecosystem contains 700,000 gallons of sea water brought in from the California coast — more than an typical Olympic-size swimming pool. Scientists suit up in scuba gear to explore ...

Biosphere 2's ocean ecosystem contains 700,000 gallons of sea water brought in from the California coast — more than an typical Olympic-size swimming pool.