Fortified Lock

Keep going straight and you might start to feel like you’re heading straight into a wall—a concrete one, no less. And you wouldn’t be wrong. But don’t worry… what’s ahead is well worth the approach! Right across from the submarine base, the fortified lock stands as another striking witness to Saint-Nazaire’s wartime past. Closely tied to the story of the U-boat base, this massive structure dates back to World War II. Starting in 1941, Nazi Germany set up operations along several key points on the Atlantic coast—including here in Saint-Nazaire—to house its submarine fleet. The scale of construction was immense, requiring more than 1,500 workers. As part of this massive defensive complex, the fortified lock was built between 1943 and 1944 to give the submarines easier access to the Loire estuary. Stretching 155 meters long and 25 meters wide, the lock remains an impressive feat of engineering. Today, it’s home to two major attractions: the legendary Espadon submarine, which you can board and explore, and the EOL Center, a modern and interactive space dedicated to offshore wind energy—produced right here, just off the coast.