In the heart of the Cotentin Peninsula in Normandy, a striking structure rises from the rolling meadows and pastures — a massive concrete hangar that looks more like a scene from a science fiction film than a relic of the past. Known as the Écausseville hangar, this 150-meter-long, ten-story-high building was originally intended to house military airships during World War I. However, despite its imposing size, it has never actually held an airship. Today, it stands as a unique historical monument, offering tourists the chance to fly through it in a modern airship. The decision to build this hangar in concrete was made in 1917, during the height of World War I, when the threat of German submarines in the English Channel prompted the French Navy to establish an aerial surveillance base. Construction began in late 1917 and continued until 1919, just months after the Armistice of November 11, 1918. The hangar was designed using the Hennebique method, an innovative technique involving reinforced concrete that allowed for the creation of strong yet lightweight structures. The building consists of 25 concrete frames and is covered with over 2,540 prefabricated tiles, making it one of the largest reinforced concrete structures in France at the time. The location of the hangar was not chosen randomly. The area around Écausseville offered natural advantages for airship operations. The land was sheltered from the strong westerly winds and provided natural updrafts, which were essential for the takeoff and landing of these large, delicate airships. In 1917, a smaller wooden hangar was built to accommodate an airship for coastal surveillance, and it was indeed used for this purpose. However, the concrete structure that followed was never put to its intended use, despite being completed in 1919. The Écausseville hangar survived the decades not because it was used, but because it was never needed. Unlike other airship hangars built during the war, which were eventually abandoned or demolished, this one remained untouched by military activity after the war. Its remote location in the Norman countryside protected it from urban development and destruction. Recognized for its historical and architectural significance, it was classified as a Historical Monument in 2003. Today, it has a new purpose: hosting tourist airship flights, allowing visitors to experience its grandeur from the air, and to appreciate its unique place in history.