In 1900, a college football game in San Francisco turned deadly when hundreds of spectators climbed onto the roof of a nearby glass factory to watch for free. The roof couldn't handle the weight and collapsed, sending the crowd plunging straight into a scorching glass furnace below. Twenty-two people died, and hundreds more suffered injuries.
Incredibly, the game didn't even stop-the players kept going as chaos unfolded nearby. The tragedy became known as the Thanksgiving Day Disaster.