"Please," said the man in the Soviet prison warder's uniform, extending his arm towards the open cell. The door shut behind us with a clang and in an instant all light vanished from the world. I heard a wooden stick being tapped against a wall, then there was nothing but the cold, still air and a musty smell like an underground drain. "This was special punishment cell," the guide resumed, pulling back the bolts. "Three hours in here, no more problems. You have any questions?"