Two of the bloodiest prison uprisings in U.S. history occurred at Attica, N.Y., and Santa Fe, N.M.

On Sept. 9, 1971, more than 1,000 rioting prisoners took over the state prison at Attica, protesting conditions. They held 36 hostages and threatened to kill them if authorities used force to retake the prison.

During the first, tense hours of the takeover, the inmates beat, stripped and then released eight guards, including one who had been thrown from a second-floor window and suffered serious head injuries. At dusk of that first day, the remaining hostages were blindfolded and held in a tight circle in the prison yard.

Four days later, 1,400 state troopers used helicopters and SWAT teams to storm the facility. The hostages, who had been dressed in prison garb to confuse the authorities, were caught in the middle. Eight hostages were among the 42 dead. Autopsies showed that they were killed in the crossfire.

Nine years after Attica, the state prison at Santa Fe became the scene of a 36-hour uprising and takeover. Thirty-three prisoners who were considered informers in the prison were taken hostage, tortured and executed by other inmates. At least two of the hostage inmates were beheaded. Eighty-nine others were injured in the melee, but all of the prison guards who were taken hostage during the uprising were eventually released unharmed.

The uprising ended when the remaining insurgent prisoners settled with state authorities at the negotiating table and then walked to the central compound area and surrendered by lying down.