In July of 1518, the town of Strasbourg, Alsace (part of the Holy Roman Empire back in the day) fell victim to some unusual disease. A woman by the name of Frau Troffea began to dance in the streets without regard. After four to six days, she was still going and managed to get 34 other people to join. After a month there were around 400 people dancing maniacally in the streets. Eventually, some of them started dying off due to heart attack, stroke, and exhaustion.
Though there is no explanation for the plague or why they danced, physicians ruled out astrological and supernatural causes, saying that the source for the plague was "hot blood." The cure? Keep dancing! Guildhalls, a grain market, and a stage were constructed for the "sick." Musicians were even brought in to encourage the grooves. They believed the dancers would recover if they continued dancing, and they eventually did, because they died.
