In September 1971, nearly 1,300 inmates in the Attica Correctional Facility in upstate New York shook the nation to its core. The bloodiest prison riot in recent American history, the four-day uprising turned the spotlight on living conditions in state penitentiaries, widespread human rights abuses committed behind bars, and the realities of incarcerated peoples. The riot created a media firestorm initially, but since then, the historic moment, often credited as birthing the modern-day prisoners’ rights movement, has largely been left out of public discourse.

Leading up to the insurrection, there was a considerable outcry from inmates about the state of the prison and the staff’s behavior. According to The New York Times, at the time, prisoners in New York state received one roll of toilet paper monthly and were allowed only one shower a week. In addition, as a rule, inmate letters written in foreign languages were discarded by overseers before reaching their intended recipients, and Islam was deemed an illegitimate faith. Moreover, in Attica specifically, the guards — most of whom were white — were said to be deeply hostile toward inmates. “I was conscious of the racial prejudice. The guards — they were vicious. They had no qualms about calling you nigger. The prison ran on anger. It ran on fright,” one of the rioters, Carlos Roche, explained in a BBC news special.

That summer, inmates drafted a list of 27 grievances, which would be resurrected in September, and sent the list to the state’s commissioner of correctional services, Russell Oswald, in an effort to make their concerns known and campaign for better overall living conditions. Their concerns went unaddressed.

The insurrection was unplanned. On September 9, 1971, due to an antiquated security system, a group of prisoners found themselves trapped in a tunnel connecting their cells to the prison yard. Fearful and concerned about their safety because of a rumor that an inmate in another prison had been killed the night before, the Attica inmates stormed into action. It’s been reported that one prisoner attacked a guard first, and then several others joined in. They proceeded to storm down the prison hallway, broke through a defective gate that led to the central yard area, known as “Times Square,” acquired a set a master keys to the prison, and then nearly 1,300 inmates banded together to seize control of the compound while corrections officers scrambled for help, to no avail (the prison’s old phone system made it difficult to make more than one call at a time).

“I came out of the shower and everything was different...looking around and a riot had erupted. People were crazy — and I got crazy with them. It was just total chaos — nobody in control,” Roche told the BBC.

During the takeover, rioters took 39 guards and prison employees hostage and cited demands for state officials, such as improved living conditions, better food offerings, and an end to mail censorship. Over the next four days, prisoners tried to negotiate with authorities, including Oswald and other state officials, regarding these concerns, while the press reported on the entire ordeal from the prison yard, after they had been invited to do so by Oswald. On the third day of negotiations, it seemed the parties were approaching an agreement, but that came to a halt when one of the prison guards, William Quinn, died due to wounds he sustained after being badly beaten and thrown from a second-story window by inmates on the first day of the rebellion. After Quinn’s death, inmates threatened to kill other guards being held hostage if they retaliated. They also added two more demands to their manifesto: asylum to a nonimperialistic country and total amnesty for anything that occurred during the riot.