Under the Treaty of Versailles, Germany was forbidden to possess long-range artillery. As a consequence, in the late 1930s, Germany committed large amounts of manpower and money into developing what became the V2 (V for Vergeltungswaffen or Vengeance) rocket. The project leader was the famous Wernher von Braun (1912-1977). Originally codenamed the A4, this weapon became the World’s first ballistic missile. Development work was done at Peenemünde but this was too far from the UK for operational launches and so launch sites were constructed in northern France, putting London within the 320km range of the weapon. At Wizernes, near St Omer, a disused quarry was excavated to provide an underground assembly and storage facility of massive size.
The excavation was commenced in October 1943 by the Todt organisation. This mammoth undertaking employed around 1,300 slave labourers. A mainline-size railway tunnel was constructed which would allow a train loaded with V2 rockets to be unloaded in complete safety. The rockets would then be assembled, stood upright and fuelled underground. The Germans believed the rockets to be at their most vulnerable when actually on the launch pad whilst final preparations were being made for firing. Although the launch pad itself had to be in the open air, the plan was for the rockets to be fully set up and to emerge from the subterranean complex already vertical, just a few minutes before lift-off.
The main railway tunnel was codenamed Ida, and the twin tunnels from which the rockets would emerge Gretchen and Gustav. Side galleries would have been used for storage, assembly and workshops. Across the quarry a smaller excavation was made to provide offices and a hospital. The whole of the site was crowned by a truly enormous concrete dome or cupola. This measures 71 metres in diameter and is five metres thick; the single slab of concrete is estimated to weigh 55,000 tonnes. The site was identified with the help of daring Allied low-level photo-reconnaissance.
The site was targetted by the Allies in 1944 as part of Operation Crossbow - the codename for the offensive against the V-weapon sites. Conventional bombing had only limited success although over 50 local residents were sadly killed. Later in the same year, the RAF used 12,000 pound Tallboy bombs which managed to cause serious damage and as a result the site was abandoned by the Germans.
The site became known locally as ‘La Coupole’ (the ‘Cupola’ or ‘Dome’) and it was with this name that the site opened as a museum in 1997. The museum is built into the underground complex itself and has extensive displays on its construction, purpose and destruction. There are also many exhibits about how World War II affected the local area more generally. Finally there is an extensive display on how the V2 laid the foundations of modern rocket technology. Von Braun and large numbers of his colleagues were recruited to work in the USA after the war in Operation Paperclip. Today the USA holds the largest number of extant V2s of any country; evidence of the relocation of physical rockets as well as personnel. Besides the displays at La Coupole, examples of V2s can be seen in the UK at the Science Museum, Imperial War Museum and at RAF Cosford.
Subterranea Britannica has been fortunate to visit the incomplete tunnels behind the public museum which add extra insight into the massive construction. Our thanks to the Museum Authorities are gratefully recorded.