A Super volcano eruption anywhere, would darken the sky for months, all over the globe, scatter ash all over the globe and within a thousand miles of the crater have ash build up to several feet thick.
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It happened in 535 ad, maybe twice, once in Indonesia and once in Mexico. The following years without summers killed off a large portion of the Holy Roman Empire. It replaced grain-eating Europeans with goat and cattle eating people from the asian steppes.
It happened in 535 ad, maybe twice, once in Indonesia and once in Mexico.
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They are not known to be super volcano eruptions - large but not as big as once thought.