In July 1518, in Strasbourg (then part of the Holy Roman Empire), a woman named Frau Troffea stepped into the street and began dancing violently. Not the fun kind, a trace- like , compulsive jig. She couldn't stop. Within a week, 34 others joined her. By August, 400 people were dancing, some until their feet bled or they collapsed from heart attacks.

There are three theories :

1. Mass Psychogenic illness
A psychological domino effect, stress (famine, disease) + belief in curses made people subconsciously mimic the dancing. Similar to modern "Twitch streamer tics" or school-wide hysterias.

2. Ergot Poisoning
A fungus (Culviceps purpurea) on rye bread causes hallucinations and spasms , the same toxin behind the Salem witch trials. But why only dancing? No reports of vomiting or visions.

3. A Forgotten Cult Ritual
Medieval Europe had dance- manias linked to saints (like St. Vitus, patron of dancers). Some think they were trying to "dance away" divine punishment.

The city's cure. They build a stage, hire musicians, and let them dance it out. It was bad idea, people died. Finally, victims were carted to a mountain shrine to pray and it stopped. No one knows why.