The Thanksgiving Day Disaster took place in San Francisco on November 29, 1900, at the annual college football game between the California Golden Bears and the Stanford Cardinal, also known as The Big Game.

On the day of the game, the San Francisco and Pacific Glass Works company had just opened a new building across 15th Street from the stadium. Because the factory was brand new, only one furnace was active that day. The remaining furnaces were not scheduled to start until a few days later. The furnace was filled with 14 tons of molten glass with a temperature of 1,650 °C.

A large crowd of people who did not want to pay the $1 (equivalent of $40 today) admission fee gathered upon the roof of a glass blowing factory to watch for free. Many factory workers attempted to tell the police, but were ignored. The peak of the factory's roof was topped by a ventilator which ran the length of the building, and was not intended to hold the weight of hundreds of people.

Approximately 20 minutes after kickoff, the roof collapsed.

Of the hundreds of people on the roof, at least 100 people fell four stories to the factory floor some being killed immediately. 60 to 100 more people fell directly on top of the furnace, the surface temperature of which was estimated to be around 260 °C. Had the people broken through the furnace, their bodies would have been consumed by the molten glass. Bodies that hit the surface of the furnaces immediately began to boil, while the victim was still alive. Fuel pipes were also severed by falling bodies, spraying many victims with scalding hot oil. The fuel ignited, setting many bodies on fire, burning the victims alive.

Some were lucky, and fell on to reinforcement beams. However, looking down would only bare the sight of men screaming in pain being essentially grilled alive.

Factory workers attempted to remove the now charcoal like bodies from the surface of the furnace by using poles to poke them.

Thirteen people were killed on the day of the disaster, with nine more dying in hospitals in the days that followed. A 28-year-old man succumbed to his injuries three years after the disaster, bringing the final death toll to 23. All of the victims were male, and most were children.

The disaster remains the deadliest accident at a sporting event in U.S. history.

A depiction of the factory, and the reinforcement beams some lucky people landed on. The furnace lay below them.

Some of the victims of the disaster.

A local newspaper clipping, the image depicts the victims as they fell on to the furnace and ground below.

A real picture of the victims atop the roof, moments before it collapsed.