They Built A Second Earth But COULDN'T BREATH!!

In 1991, eight people sealed themselves inside a glass world in the Arizona desert. Two years later, the air inside was disappearing, and no one knew why. Biosphere 2 was one of the boldest science experiments ever attempted. Funded by billionaire Ed Bass for about $150 million, it covered more than three acres of glass and steel and contained its own rainforest, ocean with a coral reef, mangrove marsh, savanna, fog desert and farm. The goal was to prove that people could live inside a completely closed ecosystem, recycling their own air, water and food, a test run for future colonies on Mars. But month after month, the oxygen dropped. From 21 percent to 20, then 19, then 18. The crew grew exhausted, woke up gasping at night and struggled to finish sentences. By 1993, the air inside was as thin as on a mountain more than four kilometers high, and managers had to break the seal and pump in oxygen from outside. Where did the oxygen go? Scientists from Columbia University followed the clues to two unexpected culprits hiding in plain sight. This is the true story of Biosphere 2: the dream, the experiment, the mystery of the missing air, and what it teaches us about the only planet that keeps us alive on its own.