* Astronomy

Outbreak of St. John's Dance in Aachen. (1374)

Dancing mania (or choreomania) was a social phenomenon that occurred primarily in mainland Europe between the 14th and 18th centuries; it involved groups of people, sometimes thousands at a time, who danced uncontrollably and bizarrely. Men, women, and children would dance through the streets of towns or cities, sometimes foaming at the mouth until they collapsed from fatigue.
One of the first major outbreaks was in Aachen, Germany, on June 24, 1374; the populace danced wildly through the streets, screaming of visions and hallucinations, and even continued to writhe and twist after they were too exhausted to stand.
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