On a Sunday afternoon in May, more than 100 people gathered on a grassy knoll sandwiched between a swamp and a construction company lot on the eastern outskirts of Memphis, Tennessee. Two high school juniors, Khamilla Johnson and Khari Bowman, stood before them and described how, exactly 99 years ago, a crowd at least 50 times as large had come to this very spot to watch the lynching of a black man named Ell Persons.
Persons, the teens recounted, had been arrested for the rape and murder of a white girl based on pseudoscientific evidence, such as a claim that his image was imprinted on her eyes. Before he could be tried, a white mob abducted him and brazenly announced the place of his torture and death. They chained him to a log, doused him in gasoline, and set him alight...