Richelieu gave the order to build a naval base here, in the Penfeld Valley, in 1631. At the end of the 19th C, a sea wall was built, creating a vast harbour where the arsenal and naval base were set up. This was followed by a submarine base, built by the occupying forces of the Second World War. Naval fans can visit the arsenal only if they have French ID cards.

The Pointe du Van lies at the southernmost tip of the Bay of Douarnenez, beyond the famous Pointe du Raz. Its magnificent landscape equals that of its neighbour, as do the winds to which it is subjected. A half-hidden path takes you round the headland, commanding fine views of the coast including the Pointe de Castelmeur, Pointe de Brézellec, Cap de la Chèvre, Pointe de Penhir, Tas de Pois and Pointe de St-Mathieu opposite. Off the coast of the Pointe du Raz stand the Île de Sein and the Vieille lighthouse. Be careful if you wish to attempt the descent.

Situated to the east of the business port, at the edge of the Moulin-Blanc harbour, Océanopolis looks ike a giant crab, in the middle of a 5 hectare park. Several giant aquariums recreate underwater life along the Brittany coastline: on the continental plateau, the Grande Vasière tidal reservour, the Grand Tombant and the Molène-Ouessant archipelago. Two buildings are devoted to polar and tropical ecosystems, and a 3D cinema has recently been added.

The Interpretation Centre of Lighthouses and buoys located in the former engine room retraces the history of these light towers from antiquity to our days. Here you will find a collection of turbines, lenses, lamps and reflectors; all of which bring to mind the keeper's functions and his life. The light of Ouessant's lighthouse is made up of four lamps which provide a luminous power of 20 million candelas and extends to an average range of over 60 km.