Bertheaume Fort

Built by Vauban in the 17th century on a rocky islet to watch over the port of Brest. The fort's geographical position meant that it could always keep an eye on the entrance to the Goulet de Brest, the arm of the sea linking Brest harbor to the Atlantic Ocean. Today, the fort is accessible via a footbridge and can be visited in summer.

For centuries, Brest's harbor has been a magnet for invaders. As early as the Middle Ages, protective posts were set up on the coast to control its entrance. The most effective of these was Bertheaume, a rocky islet thirty meters from the shore in Plougonvelin. In the 17th century, around 1690, at the request of Louis XIV, Vauban built a formidable fort here, which was used for military purposes until 1944.

At 37 meters high, Vauban wanted to protect Brest during the War of the League of Augsburg. He therefore installed three cannons and two mortars on the upper platform of the islet to control the Bertheaume cove, through which all ships entering or leaving Brest harbor still pass today. A wise decision: in June 1694, an English fleet attacked, but was greeted by a deluge of bombs from the fort, enough to repel them.

Bertheaume's usefulness was no longer in doubt, and Vauban's successors continued his work in the 18th and 19th centuries. Barracks, powder magazines and a perimeter wall were first installed, before the fort, then only accessible at low tide, was equipped with a footbridge in 1835, followed by casemates some fifty years later.

From 1940 to 1944, German troops used Bertheaume as one of their support points for the Atlantic Wall. The liberation of the islet in September 1944 marked the end of its military use, and it lay abandoned for over forty years before being bought back in 1990 by the commune of Plougonvelin, which opened it to visitors and organized regular exhibitions and sound and light shows retracing its history: Si Bertheaume m'était conté. Two zip lines and a climbing course have even been set up on the site: an opportunity to mix history and adventure! Bertheaume Iroise Aventure