For most of that time, he was kept in a dark, damp cell with no bed and no opening except a slot in the door through which a bowl of food could be pushed.
He said he was placed in a large, damp cell, stinking of urine, with 15 other detainees, each of whom was strip-searched.
His physical torture was to have contracted pneumonia in a damp prison cell and not be allowed treatment, which contributed to his fragile state ever since – but his mental torture lasted daily all his adult life.
Isolated from non-political prisoners in Section B, Mandela was imprisoned in a damp concrete cell measuring 8 feet by 7 feet, with a straw mat on which to sleep.
One of those paints, Scheele's Green, invented in Sweden in the 1770s, is thought by some historians to have killed Napoleon Bonaparte in 1821, when lethal arsenic fumes were released from the rotting green and gold wallpaper in his damp cell on the island of Saint Helena.
But the cold and damp cell was far from pleasant and there was the looming danger that the authorities would revisit his case and impose an even harsher punishment.
The techniques - described in an ABC news report last November and never denied by the US government - include enforced standing for days at a time, the confinement of naked prisoners in cold and damp cells and simulated drownings.
The circle of seats in the new conference hall rests almost exactly where two tiers of cramped and damp cells used to be.
I was put in a damp, rat-infested cell, six by seven feet wide, with one window and one door.
He said the prisoner has trouble breathing and has lost his senses of smell and taste because he is kept in a damp and stuffy cell 22 hours a day.
