The Île Sainte-Marguerite is the largest of the Lérins Islands, about half a mile off shore from the French Riviera town of Cannes. The island is approximately 3 kilometres in length and 900 metres across.
The island is most famous for its fortress prison, in which the so-called Man in the Iron Mask was held in the 17th century.
Address Chemin de la Batterie du Vengeur, 06400, France
Coordinates 43°31'18.811" N 7°2'40.182" E