For five days in 1971, more than 1,200 inmates took over a massive prison in New York state. The uprising spark nationwide news coverage, exposed troubling inequities in the U.S. prison system, and cost at least 43 lives.
The event would spur public hearings, state investigations and street protests. It would also leave such a scar in U.S. history that its remnants would become literal museum pieces.
Here's a look, in pictures, at the key players and what happened, both during the riot and after.
Smoke and fire
Smoke from burning buildings hangs in the air over Attica State Prison on September 9, 1971, the first day of a riot in which more than 1,200 prisoners took dozens of hostages.
Hundreds of prisoners can be seen in the prison yard.
The riot began in the overcrowded prison after long-simmering inmate complaints of racial bias and poor conditions. Prisoners took over the facility and took 42 staff hostage.
Here, inmates at the Attica Correctional Facility give the Black power salute. Correctional officer John Stockholm would later recount beatings and imprisonment at the hands of the rioters.
In this photo taken September 10, 1971, inmates, right, negotiate with state prisons Commissioner Russell Oswald, lower left, at the facility in Attica, New York, where inmates had taken control of the maximum-security prison.
Inmates listed 33 demands, including better medical treatment, religious freedom, higher wages for inmate jobs and basic necessities such as toothbrushes and daily showers.
Here, inmates wearing cloaks and football helmets stand behind bars in a corridor leading to "D" block as they begin negotiations state officials.
Of the 33 demands, officials conceded most, but not a request to replace the prison superintendent.
Guards line up outside Attica Correctional Facility, New York, after rioting broke out in the prison, in this photo from September 11, 1971.
State Governor Nelson Rockefeller refused to meet with inmates, but other negotiators stepped in to mediate.
Guard Phillip Watkins, right, whose right arm was broken during the September 1971 takeover, later recounted 97 hours of captivity in the Attica prison riot.
Next to him is his wife, Peggy.
State troopers at the scene
New York State troopers with weapons at the ready are pictured during the Attica prison riot.
The negotiations would eventually break down, replaced by an armed retaking of the prison by these and other forces.
Inmates at the Attica State Correctional Facility here display a fairly well-equipped hospital they have set up.
The day: September 11, 1971.
Overseeing a riot
Incredibly, police got an inside look at the area they were trying to retake during the stand-off.
Here, heavily armed police stand watch over an area of Attica State Correctional Facility still under the control of the rioting prisoners. The broken clock shows the time the riot started, 9:30 a.m. on September 9, 1971.
"My shirt was taken from me and I was given a gray shirt to put on," hostage John Stockholm later recalled.
Here's another uniform piece that survived the standoff. Prison guard Arthur Smith's corrections officer badge is pictured on his sullied uniform at his daughter, Vickie Smith Menz's home in Henrietta, New York, Tuesday, October 7, 2014. Smith was also among the corrections officers taken hostage during the riot.
Smith survived the riot, but died in 1995 from cancer. Menz was given a box containing the uniform in early September 2014.
Prison officials stand in the rain outside Attica State Prison in New York on September 10, 1971, as the prison entered its second day of disturbances.
The riot started in "A" corridor. "They were throwing rocks, anything, weight bars," a corrections officer later recounted.
Attorney William Kunstler arrives at the Attica State Correctional Facility on September 10, 1971 to discuss grievances with rebellious inmates.
Negotiating with inmates
As the riot entered a third day, more negotiators arrived to help, starting with a four-hour morning summit between the two parties.
Here, attorney William Kunstler, right, with the negotiating committee behind him, and inmates atop a guard shack in the exercise yard of cell block D, tells rebellious inmates at the Attica State Correctional Facility that he will defend them.
Black Panther Bobby Seale
Black Panther Party leader Bobby Seale, second from left, is seen here arriving at Greater Buffalo International Airport before driving to the Attica State Correctional Facility on September 11, 1971.
He was on a special citizens panel invited to intermediate with prisoners and state officials.
Black Panther Party leader Bobby Seale, left, is flanked by state police as he enters riot torn Attica State Correctional Facility.
Seale entered the maximum security prison to talk to inmates just before it was learned that a guard died as a result of injuries suffered two days earlier, during the takeover.
Inside the prison
Black Panther leader Bobby Seale is shown as he was escorted into the main gate of the Attica State Prison on Saturday, September 11, 1971 in Attica, New York.
Superintendent Vincent P. Mancusi enters the main gate at the prison, September 11, 1971.
One of the unmet demands of the prisoners was the removal of Mancusi.
Two inmates at the Attica State Prison visit with another inmate inside a makeshift hospital set up by the inmates inside cell block D on September 11, 1971.
By this point, inmates controlled about half the prison, including D-yard, two tunnels, and the central control room, referred to as "Times Square."
Preparing to fight
In this September 13, 1971 photo, prison guards and New York state troopers gather outside Attica as they prepare to enter the prison and retake it.
It had been five days. Hostages would later recall that they were tortured and threatened at the hands of inmates.
"They dropped the gas"
A helicopter hovers over Attica Correctional Facility during the final hours of the riot.
"The next thing, you could hear a helicopter," former hostage John Stockholm, who was blindfolded at the time, later recalled. "Well at that point, they dropped the gas ... you could hear the sounds and smell of pain and death."
Crushing the riot
After talks broke down, members of the National Guard would step in to retake the prison by force.
Here, National Guardsmen wearing gas masks prepare to storm cell block D, the stronghold of the rebellious convicts.
Sitting by a trench
Inmates at the Attica State Prison sit by the trench in "D" yard in this photo, made shortly after the state police halted the prison riot.
The photo, taken by state officials, was released to the news media on April 26, 1972, by a New York State special commission Investigating the prison revolt.
A burned hat of an Attica guard frames a bullet hole in the railing surrounding the yard of cell block D at Attica.
More than 10 hostages and 30 prisoners were killed when armed police and National Guardsmen staged a mass assault on the prison..
This is the exercise yard inside Attica State Prison's cell block D, where police and guards freed hostages held for five days after bombing the area with teargas on September 13, 1971.
The prisoners' command post was under the makeshift shelter at right.
A debris-strewn yard is shown with prisoners lying on the ground during the final hours of the Attica prison riot.
Counting the dead and living
After a 10-minute bloodbath that would eventually leave at least 43 people dead, the five-day prison rebellion was over.
Here, officials count the living and dead prisoners after retaking the facility.
Released hostage Paul Krotz is seen here with his family.
"The state showed no regards for my family during the riot," fellow hostage John Stockholm later recalled. "They gave them no information, no place to wait."
Surveying the remains
New York State Corrections Commissioner Russell Oswald looks over the debris-strewn yard of cell block D, where inmates held 42 hostages for five days.
It was Oswald who ordered the attack, when state police and National Guardsmen ran into the yard with blazing guns and tear gas.
Inmates at the state prison line up with their hands raised behind their heads, in this photo from September 13, 1971.
The photo was taken after their surrender.
Shown here are more weapons gathered from the area previously occupied by the rebelling inmates.
The photos were made by state police photographers at Attica State Prison on September 13, 1971.
Here's a collection of some of the weapons found after the attack on rebelling Attica prison inmates.
Note the belt hand-lettered with the word, "executioner."
The father of a slain guard breaks down as he is escorted from scene at Attica.
"Everybody was scared to death," another hostage, corrections officer Dean Wright, later recalled. "If you weren't, [you] were foolish."
The extent of destruction in cell blocks controlled by rioting inmates is shown in this September 13, 1971 photo after the prisoners were forced from the area.
At this point, prison officials were telling media that six convicts were missing and could be dead in the tunnels beneath the state prison.
Here, officials help organize bus-borne transfer of inmates out of Attica and to other state prisons, described as standard procedure after jail riots.
A state police car escorts buses out of Attica as inmates are transferred to other state prisons.
Bars and broken glass frame the destruction resulting from the mass attack by police on Attica prison.
A flag flies at half-staff at Attica Correctional Facility after hostages and inmates were killed when police attacked rioting prisoners.
"Everybody that was involved in this riot [was] injured," hostage Dean Wright later recalled. "I don't care if it was physically, mentally or both."
Mattresses, crates and rubble
Mattresses, crates and rubble fill the yard after riots at Attica State Prison.
Remembering the dead
Mourners carrying coffins of Attica convicts proceed along Lewis Avenue, Brooklyn, to Cornerstone Church in the days after the Attica uprising.
The final riot death count included three inmates who were victims of vigilante killings by fellow inmates.
Black power salute
More than 800 people crowded into the AME Zion Church in Rochester, New York, for the funeral of Elliott Barkley, one of the inmates killed in the Attica riot, on September 20, 1971.
Mourners on the outside gave the Black power salute as the casket was carried from the church to the hearse.
A casket covered with the Puerto Rican flag is borne past sea of fists.
Religious and community groups sponsored a march of about 300 people bearing the coffins of six prisoners who died in the bloodbath at Attica.
Flag of Black liberation
The red, green and black flag of black liberation is draped over a coffin as it is moved into Cornerstone Baptist Church.
The procession was viewed by thousands of the people of New York's Bedford-Stuyvesant neighborhood.
Remembering the officers
Buffalo, New York, motorcycle policemen stand at a candlelight memorial service for slain Attica State Prison employees outside the prison's main gate on September 17, 1971, in Attica, New York.
Survivors of the riot, many of them corrections officers, would later recall their struggles for fair compensation and treatment after the incident.
Grief at a graveside
Family and friends of correctional officer Ronald Werner grieve at his graveside.
Bodies such as his would later be picked up for multiple autopsies as questions lingered over how many of the dead met their fate.
Those left behind
The flag-draped coffin of Ronald Werner, an Attica guard, and that of his uncle, Elon, are borne out of an Attica funeral home.
Two of the men whom Attica mourned left eight children each.
Ronald Werner's wife receives flag.
This undated photo provided by the New York State Museum shows a piece of clothing related to the Attica Correctional Facility uprising of 1971.
The museum has received thousands of items related to the Attica prison riots.
Ray Bogart, a former correction officer taken hostage during the Attica prison riot, holds what remains of the uniform cap worn during the riot.
The hat was returned to him, at his home in Auburn, New York, on October 7, 2014.
A group of demonstrators march behind a banner that reads "Avenge Attica" and sign that states "Feel for your brothers and sisters in jail," sometime in the early 1970s.
The signs refer to the Attica prison riot.
Legacy of Attica
What happened at Attica didn't stop with Attica.
Here, African American protesters march during a protest against the violence and inequality, September 28, 1971.