Extras

    Video thumbnail: NOVA Killer Volcanoes Preview

    NOVA

    Killer Volcanoes Preview

    Scientists hunt for a mega-eruption that plunged medieval Earth into a deep freeze.

    Killer Volcanoes Preview

    Video thumbnail: NOVA Ancient Volcanic Activity in Ice

    NOVA

    Ancient Volcanic Activity in Ice

    Researchers try to prove the existence of a 13th century volcanic eruption using ice.

    Ancient Volcanic Activity in Ice