14 Historical Mass Hysteria Events That Are So Disturbing I Wish I Could Unread Them

In July of 1518, in Strasbourg, Alsace (what is now modern-day France), a woman stepped out into the street and began to dance. There was no music that started her dancing, and there was nothing that could stop her, either. Occasionally, she would collapse from exhaustion, and when she had recovered enough, she would resume dancing. She continued this way for days.

Within a week, as many as 30 more people had joined her, similarly dancing to exhaustion and even injury. 

The cause was a complete mystery, so local religious and civic leaders pondered and eventually decided that the cure to this phenomenon was more dancing. They opened up guild halls and hired musicians and professional dancers to encourage the afflicted to continue dancing. 

As you might imagine, this only made things worse.

Over the course of the next four to six weeks, as many as 400 people were afflicted by the dancing “contagion.” Author John Waller estimates in his book A Time to Dance, A Time to Die: The Extraordinary Story of the Dancing Plague of 1518 that as many as 15 people were dying from exhaustion and injury per day at the epidemic’s peak, though an exact total death count is not known.

So, what caused this phenomenon? Well, experts at the time attributed it to demonic possession (of course) or “hot blood.” But more modern investigators theorize that there could have been an outbreak of the ergot fungal disease, spread through baked goods made with contaminated flour. Others suggest that it was a mass psychogenic disorder caused by stress, as famine and diseases (like smallpox and syphilis) were causing excessive stress on Strasbourg citizens.

The wildest part of all of this? This wasn’t even the first time something like this happened. In fact, it was the last documented outbreak of many similar ones that occurred between the 10th and 16th centuries.