Ile St Marguerite (Saint Margaret Island) is about a 15-minute boat ride away from Cannes harbour. The cell of the mysterious 'Man with the Iron Mask' can be visited in the Fort of St Marguerite, now renamed the Musée de la Mer (Museum of the Sea). This museum also houses archaeological discoveries from shipwrecks off the coast of the island, including Roman and Saracen ceramics. There is a regular boat service from the mainland.
