survived the bombing intact and is still prominently visible today. Unlike its sister site at Watten, there was no on-site power plant. Electricity at Wizernes was provided by a connection to the main electric grid, with power consumption estimated at between 5,000 and 6,000 kVA. Discovery and Allied attacks The Allies became aware of the Wizernes site in August 1943 when the Germans began laying extensive new rail sidings which were spotted by RAF reconnaissance flights. Late 1943, a Belgian, Jacques de Duve, supported by German opponents, informed MI5 about the existence of a rocket production site in Saint-Omer. MI5 did not believe de Duve, who was interned for the rest of the war in Latchmere House. In November 1943, the Allied Central Interpretation Unit reported that the Germans had begun constructing the concrete dome and were undertaking tunnelling works in the east face of the quarry. However, it was not until the following March that the Allies added the site to the list of targets for the bombing campaign against V-weapon sites that had already wrecked the Watten bunker and numerous V-1 flying bomb launching sites. Over the next few months, the USAAF and RAF carried out 16 air raids involving 811 bombers that dropped some 4,260 tons of bombs. The bombing caused destruction across a wide area, killing 55 residents of the nearby village of Helfault. Conventional bombing raids only achieved a single bomb hit on the dome itself, causing negligible damage. However, in June and July 1944 the RAF began attacking the site with , ground-penetrating Tallboy bombs. The external construction works were completely wrecked by the bombing and one Tallboy landed just beside the dome, blowing out the entire quarry cliff face and burying the entrances to the Gustav and Gretchen tunnels. The entrance to Sophie was also buried, leaving Ida as the only entrance to the facility. The dome was unscathed but the buttresses supporting the protective Zerschellerplatte were dislodged and slid partway down into the quarry. Serious damage was also caused to the tunnels beneath the dome. The damage made it impossible to continue work on the site. Dornberger complained: "Persistent air attack with heavy and super-heavy bombs so battered the rock all around that in the spring of 1944 landslides made further work impossible." His staff reported on 28 July 1944 that, although the dome had not been hit by the Tallboys, "the