And it wasn't just white Tulsa. Black folks had also flocked to the city during the boom, making Tulsa home to the second-largest African American population in the state by 1921. And although segregation relegated the approximately 10,000 Black Tulsans to Greenwood, a neighborhood north of the railroad tracks that divided the city, Black leaders found a way to make that work. The neighborhood boasted office buildings for the area's Black doctors and lawyers, banks and dozens of individually owned shops. There were restaurants, beauty salons and a multi-story hotel. There was even a mortician to ensure that Greenwood residents got a properly respectful burial. Despite rejection by white Tulsa, Greenwood became so well known across the country it was often referred to by its nickname: Black Wall Street.

But all that prosperity vanished on the night of May 31, when a mob of white men — including some in law enforcement—rampaged through the neighborhood. They were inflamed by a false report of a Black teen sexually assaulting a white teen, and furious that Greenwood's Black veterans had taken up arms to prevent the boy from being lynched.

Someone — no one knows who — fired a shot, and that started everything: The mob invaded Greenwood, looting and torching Greenwood's businesses and homes. They shot resisters, and some accounts of the violence claim airplanes were used to drop homemade incendiary devices onto several buildings to accelerate the arson. The predominantly wooden structures burned to the ground. No help came from Tulsa's police department, and armed white men prevented firefighters from battling the blaze .