Greenwood was a Black district of Tulsa prosperous enough to be called Black Wall Street: it had its own hotels, cinemas, doctors, newspapers and a bank, built because segregation meant its residents' money circulated nowhere else. On 31 May 1921 a nineteen-year-old shoeshiner was accused of assaulting a white lift operator, an accusation never substantiated and later dropped. A white mob gathered at the courthouse; armed Black veterans came to prevent a lynching; a shot was fired.

Over the following eighteen hours white mobs, some deputised and armed by city officials, burned thirty-five blocks to the ground, and private aircraft were used to fire on people and drop incendiaries. Somewhere between one and three hundred people were killed and about ten thousand were left homeless. No one was prosecuted. Insurance claims were refused on riot clauses. The massacre was left out of Oklahoma school textbooks for half a century, and searches for mass graves began only in 2020. A memorial park now stands in Greenwood, and the surviving section of the street is a National Historic Landmark.