“That resentment in Tulsa was so intense,” says Carol Anderson, “it was just waiting for a spark in order to ignite it.” That spark was a sexual assault allegation against a black teenager named Dick Rowland. It’s not entirely clear what happened in the elevator of the Drexel Building on May 30, 1921, but one common narrative is that Rowland accidentally tripped against its operator, a white 17-year-old named Sarah Page, causing her to scream.

A bystander who heard the scream called the police, and “like a game of telephone, the story became more inflammatory with each retelling, and spread rapidly,” writes Dexter Mullins.

When Rowland was captured, a few black World War I veterans from Greenwood armed themselves in front of the courthouse, prepared to prevent a lynching. They were justified in their fear — a man named Roy Belton had been lynched in Tulsa the year before, after his arrest. “The lynching of Roy Belton,” read Greenwood’s black newspaper The Tulsa Star in 1920, “explodes the theory that a prisoner is safe on the top of the Court House from mob violence.”

In front of the courthouse where Dick Rowland was being kept, a group of white men approached the black men from Greenwood. “Nigger, what are you going to do with that pistol?” said one.

“I’m going to use it if I need to,” the black man replied.

The white man attempted to wrest the pistol from his hands, and a gunshot rang out. It’s unclear whether it was accidental, a warning shot, or an attempt to injure or kill. In any case, all hell broke loose.

The groups of white and black men had a running gunfight all the way to Greenwood. When they got there, the group of whites — which had grown in number — began firing indiscriminately on black bystanders. Black people were shot in the streets, and dragged behind cars with nooses tied around their necks. Their houses and businesses were looted and burned down. Greenwood residents fired back, and there were white casualties as well. Ultimately, the white mob was larger and better armed.

Many eyewitness accounts mention planes flying overhead. One, written by the black lawyer Buck Colbert Franklin, reads: “Smoke ascended the sky in thick, black volumes and amid it all, the planes — now a dozen or more in number — still hummed and darted here and there with the agility of natural birds of the air… The sidewalks were literally covered with burning turpentine balls.”

An official report published by the city in 2001 confirmed that some of the planes were flown by police conducting reconnaissance. The others, it concluded, were probably piloted by white civilians who fired ammunition and dropped bottles of gasoline on the buildings below.

In the middle of the night, the Tulsa police formally requested that the National Guard assist them in quelling what they called a “Negro uprising.” As they awaited the National Guard, they let Greenwood burn.

When the soldiers arrived, they detained 6,000 black residents, many of them for more than a week. Upon release, these residents were homeless. In 2016 numbers, more than $30 million worth of property damage was sustained.

“Tulsa civic leaders clung to conservative estimates,” writes historian Tim Madigan, but “the number of the dead no doubt climbed well into the hundreds, making the burning in Tulsa the deadliest domestic American outbreak since the Civil War.”