Extras

    Video thumbnail: NOVA These Boulders are Alive

    NOVA

    These Boulders are Alive

    Dive down to rare stromatolites—key clues to the evolution of virtually all complex life.

    These Boulders are Alive

    Video thumbnail: NOVA How Panama Changed the World

    NOVA

    How Panama Changed the World

    Two scientists scan islands off Panama for clues to determine how the country was formed.

    How Panama Changed the World

    Video thumbnail: NOVA Making North America: Life Preview

    NOVA

    Making North America: Life Preview

    How did massive volcanic eruptions, inland seas, and land bridges pave the way for life?

    Making North America: Life Preview