Fort de Bertheaume

The military use of the site began even before the current structure; a predecessor was first mentioned in 1474 and was likely destroyed in 1558. In the late 17th century, specifically 1694, Vauban had a gun battery built here to protect the Bay of Brest, which had been developed into a significant military port under Cardinal Richelieu. This position played an important role in the Battle of Camaret. The current structure, including a powder magazine located 13 meters underground, dates from the mid-18th century. A bridge, built in 1835, improved accessibility, as the fortress was previously only reachable by boat. In the 1880s, bunker facilities were added. During World War II, the fort was used by German units as part of the Atlantic Wall and offered fierce resistance during the Battle of Brittany. After the war, the island reverted to the French Ministry of Defense but lost its military function. In 1990, the municipality of Plougonvelin acquired the site, after which archaeological research uncovered the fort's history and prepared it for visitors. The pedestrian bridge had to be rebuilt multiple times due to storm damage. On the mainland, there is now an open-air stage, a climbing garden, a menhir ensemble installed in the 1990s, and barbecue areas.

Fort de Bertheaume is situated in Plougonvelin, in the Finistère department of the Brittany region, France, at an elevation of approximately 2 meters above sea level.

Visitors can explore the historic fortress today. The island is accessible via a pedestrian bridge, which has been rebuilt multiple times after being destroyed by storms. On the mainland, an open-air stage, a climbing garden, a menhir ensemble, and barbecue areas complement the offerings.

• Fort de Toulbroc'h (fortress), approx. 5.1 km away
• Fort du Petit Minou (fortress), approx. 6.2 km away
• Fort du Mengant (fortress), approx. 8.2 km away
• Fort de Toulinguet (fortress), approx. 8.5 km away