In 1986, a crowd of over 100,000 people gathered in downtown Cleveland, Ohio for an event called Balloonfest ‘86. Organizers hoped to raise money for charity and to set a new world record by releasing 1.5 million balloons simultaneously.
But things went terribly wrong.
Balloon releases are typically harmless. Helium-filled balloons stay airborne until they fully deflate. Even in large numbers, they scatter to the wind and fall harmlessly back to Earth over a wide area.