Location: If, France
Notable Residents: Gaston Crémieux, Edmond Dantès
Amenities: Poor prisoners lived beneath the prison, while the wealthy ones could have fireplaces

Originally designed as a fortress, Château d'If is a three-story building with three large towers that all boast huge gun embrasures. The château was built during the 16th century. The strong currents surrounding the castle make it a site similar to Alcatraz. It was used to hold political and religious prisoners, and soon became one of the most notorious prisons in France. Over 3,000 Huguenots were sent there, including Paris Commune leader Gaston Crémieux, but the Château d'If's most famous prisoner is a fictional character.

Alexandre Dumas elected to use the prison as a key setting for his classic novel The Count of Monte Cristo. The book's protagonist, Edmond Dantès, and his mentor, Abbé Faria, are both imprisoned there. After fourteen years, Dantès becomes the only person to escape from the prison and actually survive (no one is known to have accomplished this in reality).

During those times, prisoners were treated in accordance with their wealth. The poorer inmates were held in a windowless dungeon beneath the château, while those with money lived rather comfortably in private cells with windows and the occasional fireplace. However, the wealthier prisoners were expected to pay for their amenities, essentially financing their own incarceration—the ultimate swindle. The prison was demilitarized at the end of the 19th century, but was opened to the public; it can now be reached by boat.

Mark Twain visited the prison prior to it opening to the public and claimed to have visited the cell where the "Man in the Iron Mask" was held. This is most likely a fable, as the Man in the Iron Mask was never imprisoned at the Chateau d'If. There are, however, cells named after Edmond Dantès and Abbé Faria, as The Count of Monte Cristo is responsible for making the prison famous.