(CNN) -- Tommy Silverstein has been held in solitary confinement for the past 27 years, longer than anyone else in the federal prison system, his lawyers say.
He is locked up at the high-security prison in Florence, Colorado, known as Supermax. The lights are always on. Guards who slip him food through a slot in his cell door usually ignore him. A few times a week, he is permitted to exercise in the recreation room -- alone. Visits with his family and his lawyers are conducted through Plexiglas.