One of the most mysterious and unsettling historical facts involves the "Dancing Plague" of 1518 in Strasbourg, France. Dozens of people began dancing uncontrollably in the streets, with no clear cause. This bizarre phenomenon lasted for weeks, leading to some collapsing from exhaustion or even dying from heart attacks and strokes. Despite many theories, including mass hysteria or ergot poisoning from moldy bread, no definitive explanation for this strange outbreak has ever been confirmed.