In Colfax, Louisiana, is one of “those beautiful statues and monuments” President Trump tweeted about Thursday morning, a 12-foot obelisk in a graveyard that celebrates three white men who died while participating in the massacre by a white mob of up to 150 black men, women and children.

“Erected to the memory of the heroes, Stephen Decatur Parish, James West Hadnot, Sidney Harris, who fell in the Colfax riot fighting for white supremacy, April 13, 1873,” it reads. There is no mention of the 150 black victims.

The massacre—the worst mass killing of the period—and the monument are little known. But the racial slaughter marked the last gasp of Reconstruction, the short-lived federal attempt to give freedmen true equality after the Civil War, and led directly to the Jim Crow system that lasted for another 80 years.