Geologists discover alien deposits on the Earth's surface - and the answer could shed light on the cause of the greatest extinction in its history.

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  • {S}03.{E}21. Stonehenge On Mars

    S03.E21. Stonehenge On Mars

    A NASA probe captures an image of a familiar structure on the surface of Mars. What made 'Mars Henge'? Plus, how did an Apollo astronaut get sick in on the Moon?
    Duration: 44 Min