Château d’If

The Château d'If is a French fortress built by order of King François I between 1529 and 1531 on the islet of If, part of the Frioul archipelago, close to the islands of Pomègues and Ratonneau in the centre of Marseille's harbour.

It is a square-shaped, three-storey structure measuring 28 metres per side, flanked by three casemated corner towers with wide embrasures. The rest of the island, which is only three hectares in size, is heavily defended by a bastioned perimeter wall, with artillery platforms surmounting the cliffs.

A modern-era fort, it is a masterpiece of military architecture from a period when medieval fortification was transitioning to bastioned fortification designed to meet the demands of naval artillery. It primarily served as a prison during its 400 years of official use. Alexandre Dumas made the edifice famous by having his characters Edmond Dantès and Abbé Faria, whose story is recounted in The Count of Monte-Cristo, stay there. It is one of the most visited sites in the city of Marseille and was classified as a historical monument on 7 July 1926.

The Centre des monuments nationaux opens the site to the public while maintaining it.

Since 2012, the island of If has been part of the Calanques National Park.