La Coupole (English: The Dome), also known as the Coupole d'Helfaut-Wizernes and originally codenamed Bauvorhaben 21 (Building Project 21) or Schotterwerk Nordwest (Northwest Gravel Works), is a Second World War bunker complex in the Pas-de-Calais department of northern France, about 5 kilometres (3.1 mi) from Saint-Omer, and some 14.4 kilometers (8.9 miles) south-southeast from the less developed Blockhaus d'Eperlecques V-2 launch installation in the same area.