Chateau d If

The Chateau d'If is a fortress (later a prison) located on the island of If, the smallest island in the Frioul Archipelago situated in the Mediterranean Sea about a mile offshore in the Bay of Marseille in southeastern France. It is famous for being one of the settings of Alexandre Dumas' adventure novel The Count of Monte Cristo.

The chateau is a square, three-story building 28 m long on each side, flanked by three towers with large gun embrasures. The remainder of the island, which only measures 30,000 square metres, is heavily fortified; high ramparts with gun platforms surmount the island's cliffs.