In the summer of 1518, something strange happened in the city of Strasbourg.

A woman stepped into the street and started dancing.

There was no music. No festival. No celebration. She just… danced. For hours. Then days.

Within a week, dozens of people had joined her. Within a month, hundreds were reportedly dancing nonstop in what became known as the Dancing Plague of 1518.

People collapsed from exhaustion. Some reportedly died from heart attacks or strokes. And instead of stopping it, city leaders made it worse. Believing the dancers needed to “dance it out,” officials hired musicians and cleared space for them to continue.

Why did it happen?

Historians still debate it. Some believe it may have been mass hysteria triggered by extreme stress, famine, and disease. Others once suggested ergot poisoning (a mold that grows on rye), though that theory is widely questioned today.

What makes this story fascinating isn’t just that it happened — it’s that no one fully understands why.

History isn’t always wars and kings. Sometimes it’s an entire city that couldn’t stop dancing.