It was built by the forces of Nazi Germany between 1943 and 1944 to serve as a launch base for V-2 rockets directed against London and southern England and is the earliest known precursor to modern underground missile silos still in existence.

Constructed in the side of a disused chalk quarry, the most prominent feature of the complex is an immense concrete dome, to which its modern name refers.

[4] Following repeated heavy bombing by Allied forces during Operation Crossbow, the Germans were unable to complete the construction works and the complex never entered service.

Exhibits in the tunnels and under the dome tell the story of the German occupation of France during World War II, the V-weapons and the history of space exploration.

[5] Although Adolf Hitler was at first ambivalent, he eventually became an enthusiastic supporter of the V-2 programme as Allied air forces carried out increasingly devastating attacks on German cities.

The missile's operational range of 320 kilometres (200 mi) meant that the launch sites had to be fairly close to the English Channel or southern North Sea coasts, in northern France, Belgium or the western Netherlands.

The bunker was soon spotted by Allied reconnaissance, and on 27 August 1943, a raid by 187 Boeing B-17 Flying Fortress bombers wrecked the construction site before it could be completed.

[10] On 30 September 1943, Hitler met with Albert Speer, the Minister of Armaments and War Production, and Franz Xaver Dorsch, the chief engineer of the Todt Organisation, to discuss plans for a replacement for the out-of-commission Watten facility.

Dorsch proposed to transform the Wizernes depot into a vast bomb-proof underground complex that would require a million tons of concrete to build.

Beneath it, about 7 kilometres (4.3 mi) of tunnels were to be dug into the chalk hillside to accommodate workshops, storerooms, fuel supplies, a LOX manufacturing plant, generators, barracks and a hospital.

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.

[16] 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.

[20] The remainder were slave labour: principally Frenchmen conscripted by the Service du travail obligatoire (STO), plus Soviet prisoners of war.

[9] The project was overseen by several large German construction companies, with Philipp Holzman A.G. of Frankfurt am Main and the Grossdeutsche Schachtbau and Tiefbohr GmbH serving as the chief contractors.

[21] 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.

[10] Late 1943, a Belgian, Jacques de Duve, supported by German opponents, informed MI5 about the existence of a rocket production site in Saint-Omer.

[25] 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.

[16] 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.

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.

The site was finally abandoned a few days before the Allies reached it at the start of September during the rapid liberation of the area by British, American, Canadian and Polish troops.

[32] Shortly after the Wizernes site had been captured in September 1944, Duncan Sandys, the head of the British "Crossbow Committee" investigating the V-weapons programme, ordered the constitution of a Technical Inter-Services Mission under Colonel T. R. B. Sanders.

[39] The purpose of the Wizernes site had been unclear prior to its capture but Sanders was able to deduce its connection with the V-2 from the dimensions of the complex and some intelligence information that his team had been able to retrieve.

"[21][Notes 1] He concluded that much of the site was becoming unsafe due to the progressive collapse of timbering and recommended that the tunnels and workings under the dome should be destroyed to prevent subsequent accidents or misuse.

[24] In 1986, the Espace Naturel Régional in Lille earmarked 10 million francs to develop the site as a tourist attraction for the Nord-Pas-de-Calais region with the intention of establishing a World War II Museum there.

The plan was publicised in a special open weekend on 20–21 June 1987, attended by over 20,000 people, in which the dome's designer Werner Flos met Professor Reginald Victor Jones, a surviving member of the "Crossbow Committee", at Wizernes.

[22] Local historian Yves le Maner was charged with the task of developing the project while a feasibility study was conducted into the possibility of completing some of the original excavation work to make the site safe for public access.

The tour continues along the Mathilde tunnel to reach a lift that has been installed to bring visitors up to the space beneath the dome, where the main exhibition area is located.

[41] Focusing on the story of the V-weapons, life in occupied France, and the conquest of space after the war, the tour presents audio-visual displays in English, French, Dutch and German.