Picture eight people sealing themselves inside a $150 million, three-acre glass terrarium meant to be a perfect backup for Earth. Within months the trees collapse for lack of wind, cockroaches take over, the crew secretly eats seed stocks out of hunger, and the building's own concrete quietly suffocates them by sucking oxygen from the air. It sounds like dystopian fiction, but it all really happened.

This episode dives into Biosphere 2, the audacious 1990s experiment to see if humans could engineer a closed world. We trace the brilliant engineering, the cascading ecological failures, the psychological breakdown of the crew, and the corporate warfare that followed. It matters because the project's greatest lesson was not about colonizing space but about how impossibly delicate the real Earth truly is.

• How the airtight glass dome b ...