The Blockhaus d'Éperlecques, also known as the Watten bunker, is a massive German military bunker complex from World War II, located near the town of Éperlecques in the Pas-de-Calais region of northern France. Constructed between 1943 and 1944 as part of the Nazi V-weapons program, its intended purpose was the assembly, storage, and launch of V-2 rockets, making it a critical component of Germany's late-war offensive strategy against Allied targets. The bunker's formidable construction, featuring extremely thick reinforced concrete walls and ceilings, was designed to withstand Allied air raids, though it was never fully completed or operational due to sustained bombardment and the advancing Allied forces.
Architecturally, the site is a prime example of German Regelbau (standardized construction) bunker design on an immense scale. Its most prominent surviving feature is a colossal, partially ruined launch hall with a roof over 5 meters thick in places. The complex also included extensive underground tunnels, storage rooms, and facilities for handling the volatile rocket fuel and warheads. Its geographical location in the occupied Pas-de-Calais was strategically chosen to place launch sites within striking distance of London, though the bunker's ultimate fate was sealed by the relentless Allied air campaign that targeted the entire V-weapon infrastructure.
Today, the Blockhaus d'Éperlecques is a protected historical monument and operates as a museum open to the public. It stands as one of the most imposing and well-preserved remnants of the Atlantic Wall and the V-weapon program in France. The site provides a stark, concrete testament to the industrial scale of Nazi military engineering and the intense technological warfare of the later stages of World War II. Visitors can explore the vast ruins, view exhibitions on the V-2 program, and understand the bunker's role within the broader context of the German fortifications along the French coast.