Ok, one more thing...
In explaining this video, I'm quoting here directly from Wikipedia. The video, of course, comes with its own explanation, but I happen to like this one better:
"The outbreak began in July 1518, when a woman, Frau Troffea, began to dance fervently in a street in Strasbourg.This lasted somewhere between four to six days. Within a week, 34 others had joined, and within a month, there were around 400 dancers. Most of these people eventually died from heart attack, stroke, or exhaustion.
Historical documents, including "physician notes, cathedral sermons, local and regional chronicles, and even notes issued by the Strasbourg city council" are clear that the victims danced. It is not known why these people danced to their deaths, nor is it clear that they were dancing willfully.
As the dancing plague worsened, concerned nobles sought the advice of local physicians, who ruled out astrological and supernatural causes, instead announcing that the plague was a "natural disease" caused by "hot blood". However, instead of prescribing bleeding, authorities encouraged more dancing, in part by opening two guildhalls and a grain market, and even constructing a wooden stage. The authorities did this because they believed that the dancers would only recover if they danced continually night and day. To increase the effectiveness of the cure, authorities even paid for musicians to keep the afflicted moving.
Historian John Waller thinks that the dancing epidemic was caused by mass psychogenic illness (MPI), a manifestation of mass hysteria that is often preceded by extreme levels of psychological distress. Waller states that famine had been prevalent in the region for some time, caused by very cold winters, very hot summers, crop frosts, and violent hailstorms. Mass deaths followed from malnutrition, and those who survived were forced to kill their farm animals, take out loans, and perhaps even beg in the streets. In addition to food shortages, diseases such as smallpox, syphilis, leprosy, and "the English sweat" (a new disease) afflicted the populace. This series of events might have triggered the MPI."
Enjoy the video: