But on the morning of Aug. 16, 1951, the tranquility of Pont Saint Esprit was dramatically disturbed. Madness invaded the town streets, as some of the inhabitants were struck by a mystery illness. Scenes of mass insanity and hallucinations followed for days.

“People were starting to hit each other, people were insulting one another, people were screaming. It was very serious,” Paul Pages, who was 26 years old at the time, told ABC News. “There was a young guy who jumped out of a hospital window after screaming ‘Look, I’m a dragonfly’. He broke both of his legs,” Pages remembered. “The postman was also seen zigzagging on his bike. He eventually fell. He had lost his reason.”

Seven people died and several dozen were sent to psychiatric hospitals. Hundreds of others were also affected to varying degrees by this mystery illness.