Almost 100 years ago Tulsa in Oklahoma was the site of a massacre that is considered to be the single worst case of racist violence in US history.
It is also the city where president Donald Trump decided to hold his first campaign rally since lockdown this weekend.
On Friday Trump promised a "wild evening" for his supporters. He used Twitter to threaten “protesters, anarchists, agitators, looters or lowlifes” in the city that they would “not be treated” in the same way they have in other parts of the country.
For two days beginning on 31 May 1921, a mob set fire to hundreds of black-owned businesses and homes.
Around 300 black people were killed. More than 10,000 black people were left homeless, and 40 blocks of houses, shops and businesses were left smouldering.
Survivors recounted black bodies loaded on trains and dumped off bridges into the Arkansas River or tossed into mass graves.
In the early years of the twentieth century black people had flocked to Oklahoma in the hope of jobs in the oil and mining industries .
Tulsa's population surged from 10,000 to 100,000 between 1910 and 1920.
It was a rigidly segregated city but became home to a thriving black area called the Greenwood district. This was dubbed “The Black Wall Street”.
White politicians and company executives felt under threat from workers’ struggle as well as black people who were challenging the strict racial categories that were supposed to apply under the “Jim Crow” laws.
A great wave of workers' struggles had taken place across the US in the years after the First World War and the Russian revolution.
Bosses used the racist Ku Klux Klan to break black and white workers' unity and intimidate union organisers—or murder them.
Imposition of racism and seeking to divide workers went hand in hand.
The historian James Hirsch described how in Oklahoma, “As communal events, lynchings were designed to intimidate and, when applied to Blacks, to reinforce the racial hierarchy that had been codified into law. The macabre rituals were featured on postcards, showing the victim's well-dressed audience holding umbrellas to shade themselves from the sun, that delivered the message of fear.”
The 1921 violence in Tulsa began when a white mob attempted to lynch a young black man named Dick Rowland.
Rowland had been accused of assaulting Sarah Page, a white lift operator.
Page never pressed charges against Rowland. But this didn’t stop the racists.
The afternoon edition of the Tulsa Tribune newspaper carried the story with the headline “Nab negro lad for attacking the girl in an elevator.”
On 31 May a group of white men trying to lynch Rowland fought with black people who had come to protect him. The police and the National Guard joined in to assault black people.
B C Franklin, a Greenwood lawyer, wrote an eyewitness account of the massacre. “The sidewalk was literally covered with burning turpentine balls,” he wrote.
“For fully 48 hours, the fire raged and burned everything in its path and it left nothing but ashes and burned safes and trunks and the like that were stored in beautiful houses and businesses.”
He also said, “Where oh where is our splendid fire department with its half dozen stations? I asked myself. ‘Is the city in conspiracy with the mob?’”
The final battle in the riot was a National Guard assault on the black Mount Zion Baptist church. The guardsmen used a heavy machine gun to demolish the building.
This is the city where Trump called an election rally just as Black Lives Matter protests sweep the country.
Once again a multiracial movement is beginning to challenge racism in the US. It can learn from the past about the ruthlessness of the ruling class and the need for fundamental change.