A unique opportunity, without repercussions or criminal records, to explore the most notorious prisons, forever ingrained in national culture. For some, these prisons became dungeons; for others, they were homes. Revolutionaries, scientists, politicians, writers, and poets, as well as confirmed recidivists and especially dangerous criminals, have passed through their walls. Everyday life and carefully guarded secrets, revelations from staff and stories from prisoners, historical accounts, and an impartial outsider's perspective—life inside a "system" you never even knew existed.