Syrian authorities are committing torture on a "massive scale" in government prisons including beatings, electric shocks, rape and psychological abuse that amount to crimes against humanity, Amnesty International says.
Beatings, inhumane conditions and inmates forced to rape each other. This is what goes on in one of the world's worst prisons.
And these revelations are just the beginning of what really takes place inside Syria's notorious Saydnaya Military Prison.
Based on interviews with 65 former inmates, human rights group Amnesty International teamed up with forensic architects from London's Goldsmiths University to recreate the infamous prison in a 3D video.
Amnesty International estimates 17,723 people have died in custody in Syria since the crisis began in March 2011 - an average rate of more than 300 deaths a month.
Salam Othman, a lawyer from Aleppo, spent almost two and a half years inside the prison for organising peaceful protests.
He said guards were happy to welcome the prisoners and they were beaten as they arrived.
This journey is often lethal, with detainees being at risk of death in custody at every stage.
Another inmate told Amnesty: "You eat on command, you sleep on command and you go to the toilet on command."
The beatings were brutal and long.
One former inmate said they were a daily ritual.
"When we were beaten in front of the cells there was a lot of blood on the floor," he said.
"There was a rancid and bloody smell."
Director of Amnesty International's Middle East and North Africa programme Philip Luther said conditions inside were exceptionally hard and some inmates died from a simple cut caused by lack of medical care.
He said the prison was overcrowded, full of disease and inmates were not given enough food to eat.
Inmates not only reported regular torture but had witnessed others dying in custody and even being held in cells alongside dead inmates.
Luther said the video aimed to show in gruesome detail the dreadful abuse detainees routinely suffered from the moment of their arrest until they were behind bars.
"This journey is often lethal, with detainees being at risk of death in custody at every stage," he said.
He said Syrian government forces had used torture as a means to crush their opponents, however he said it was now being carried out as part of a systematic and widespread attack against anyone suspected of opposing the Assad regime.
CRUSHED FROM THE START
Detainees told Amnesty their horror would begin the moment they stepped inside prison where guards would hold a "welcome party" which involved beatings with bars and cables.
One inmate said they were treated like animals.
"They wanted people to be as inhuman as possible ... I saw the blood, it was like a river," he said.
Others revealed they were tortured to extract confessions and were subjected to methods including dulab (forcibly contorting the victim's body into a rubber tyre) and falaqa (flogging on the soles of the feet).
Some had nails ripped out or held in stress positions.
They also reported massive overcrowding and having to take turns to sleep.
Salam, the lawyer from Aleppo, revealed how a kung fu fighter was beaten to death after guards discovered he had been training others.
"They beat the trainer and five others to death straight away, and then continued on the other 14," he said. "They all died within a week. We saw the blood coming out of the cell."
Inmates also revealed how guards would set out to deliberately humiliate them and degrade them as much as possible.
One described how a guard forced two men to strip naked and ordered one to rape the other, threatening that if he did not do it he would die.
Another inmate, who was arrested by military intelligence agents in Aleppo in 2011 described how he was raped by one of his interrogations.
"All of this time I was blindfolded. I was hung from my left hand, my shoulder was dislocated. I lost the feeling in my hand," he told Amnesty.
"While I was hanging in the shabeh position with one hand, they used an electroshock baton to hit my penis. Then they took the electroshock device and inserted it into my anus and switched it on. This was my first experience of rape. Then one of the guards asked for my face to be uncovered and I saw my father there. He had witnessed all of it."
