Sealed off from the surface for around 5 million years, Romania’s Movile Cave hides an ecosystem that runs entirely without sunlight, powered instead by chemosynthesis. In this episode we descend into a toxic, oxygen-poor world filled with dozens of species found nowhere else on Earth, and explain how life here survives on chemicals rather than the sun. Learn what makes Movile a living laboratory for understanding extreme environments — and even the possibility of life beyond our planet.

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