L'Île des Vieilles is an island of red rock culminating at 36 ft (11 m) located east of Saint-Raphaël, off Anthéor. It is part of the Estérel massif, of which it is the largest islet. The rhyolite characteristic of the whole massif gives l'Île des Vieilles its color and testifies to its volcanic origin. Used to prevent the risk of shipwreck, it hosts a cardinal beacon known as La Chrétienne on its southern tip. The name of the island comes from the French vernacular denomination of a Mediterranean fish, Labrus bergylta, and reminds that the area constitutes a remarkable diving site.