Château D'If Fortress On The Island Of If, Frioul Archipelago, Bay Of Marseille, Mediterranean Sea, France

Prison
The isolated location and dangerous offshore currents of the Château d'If made it an ideal escape-proof prison, very much like the island of Alcatraz in California was in more modern times. Its use as a dumping ground for political and religious detainees soon made it one of the most feared and notorious jails in France. Over 3,500 Huguenots (French Protestants) were sent to If, as was Gaston Crémieux, a leader of the Paris Commune, who was shot there in 1871.
The island became internationally famous in the 19th century when Alexandre Dumas used it as a setting for The Count of Monte Cristo, published to widespread acclaim in 1844. In the book, the main character Edmond Dantès (a commoner who later purchases the noble title of Count) and his mentor, Abbé Faria, were both imprisoned in it. After fourteen years, Dantès makes a daring escape from the castle, becoming the first person ever to do so and survive. In reality, no one is known to have done this. The modern Château d'If maintains adjacent cells named after Dantès and Faria as a tourist attraction.
As was common practice in those days, prisoners were treated differently according to their class and wealth. The poorest were literally placed at the bottom, being confined to a windowless dungeon under the castle. The wealthiest were much better off, living comparatively comfortably in their own private cells (or pistoles) higher up, with windows, a garderobe and a fireplace. However, they were expected to pay for this privilege, effectively forcing them to fund their own incarceration.