On May 4, 1886, a bomb went off in Chicago that ignited one of the nation's first red scares. The blast killed seven police officers and led to the hanging of four anarchists accused of plotting the attack.

Historian James Green's book Death in the Haymarket explores the tensions that led to the explosion and the panic that followed.

He talks with Debbie Elliott about a period of paranoia in American life, and the ways the violence helped to shape the modern labor movement.

Copyright 2023 NPR. To see more, visit https://www.npr.org.