|Aerial photo shows the results of the first bombing raids. |
La Coupole ("The Cupola") is the name of a Second World War V-2 rocket base constructed by Nazi Germany at Wizernes, south west of the French town of Saint-Omer, between Lille and Calais.
Set in a former limestone quarry close to the villages of Helfaut and Wizernes, the complex was intended to be an impregnable underground production and launch facility for the rockets.
Work on the site was begun in October 1943 using forced labour under the direction of the Todt Organisation with the intention of quickly building a site that could threaten London, 200 km to the north west. La Coupole's predecessor as launch site was the nearby blockhouse at Eperlecques which had been found to be too vulnerable to aerial bombardment.
Railway tunnels were bored underground to allow the rocket parts to be brought in safely. In total more than 6 km of galleries were dug by the Soviet prisoners in order to store the rockets 42 m underground. A liquid oxygen fuel plant was also built to supplement the supply from the now redeployed Eperleques site and underground barracks and administrative areas were dug out and lined with concrete.
In January 1944 an enormous concrete dome, or cupola, was built over the top of the facility, giving the site its name. The dome was 71 m in diameter, 5 m thick and weighing an estimated 55 000 tonnes.
The Nazi engineers were able to build such a vast structure using poured reinforced concrete by moulding the chalk beneath into a convex shape and then laying the concrete on top. Once it had set, they quarried the chalk away from underneath, leaving a hollow space below the dome. Underneath this space was laid a second concrete layer, the gap between adding to the dome's bomb resistance.
Directly beneath this structure a vast hexagonal room, 21 m high, was planned to house the rocket production facility. Once assembled and fuelled the rockets were to be moved outside and fired, at a rate of 40-50 per day.