passageway. The two passageways were angled at 64° 50' and 99° 50' west of north respectively—not aligned with any probable target but merely permitting the rockets to be transported to either one or the other, of their pair of sufficiently-separated launch pads. The facility was designed, as was its predecessor at Watten, to receive, process and launch V-2 rockets at a high rate. Trains carrying V-2s would enter the heart of the complex through the Ida rail tunnel, where they would be unloaded. A large number of V-2s could be stored in the side tunnels; LOX would also be produced on-site ready for use. When the time came, the rockets would be moved into the octagonal preparation chamber where they would be lifted to a vertical position for fuelling and arming. From there they would be transported on motorised launch carriages, still in a vertical position, through the Gustav and Gretchen passageways. The launch pads were located at the end of the track on the floor of the quarry, from where the missiles would be fired. The priority target for the V-2s was away: London, which Hitler wanted to see pulverised by the end of 1943. The Allies were alarmed when an analyst found that part of the complex was aligned within half a degree of the Great Circle bearing on New York, and its equipment was large enough to accommodate a rocket twice the size of the V-2: the "America Rocket", the proposed A10 intercontinental ballistic missile. Although physically separate, another facility built in nearby Roquetoire was an integral part of the Wizernes complex. Umspannwerk C was built to house a Leitstrahl radio command guidance system which could be used to send course corrections to missiles launched from Wizernes to fine-tune their trajectory during the launch phase. Construction The Allies first noticed construction activity at Wizernes in mid-August 1943 when the Germans began building railway track and the offloading stores into the old quarry. After Hitler authorised the decision to turn the depot into a missile launch site, construction was stepped up. Work on the dome began in November 1943 and tunnelling in the cliff face below began in December. At the start of January, Allied reconnaissance aircraft observed an elaborate system of camouflage on the hill top, installed to conceal the dome. The building works were greatly hindered by the constant air-raid warnings, which stopped work 229 times