This archipelago is France's largest nature reserve (280ha). Boat trips leave from Trestraou and take visitors around the islands: first Rouzic, inhabited by an impressive colony of Northern gannets, then the Île de Malban and Île de Bono, before reaching the Île aux Moines. See the gunpowder store, the lighthouse (remarkable panoramic view), then the fort - built by Vauban and now partly in ruins - and the old monastery. On the way back there is a view over the pink granite rocks.