With Germany's occupation of the Pas-de-Calais region in northern France, the possibility of closing the Strait of Dover to Royal Navy warships and merchant convoys by the use of land-based heavy artillery became readily apparent, both to the German High Command and to Hitler. Even the "Kriegsmarine"'s Naval Operations Office deemed this a plausible and desirable goal, especially given the relatively short distance, , between the French and English coasts. Orders were therefore issued to assemble and begin emplacing every Army and Navy heavy artillery piece available along the French coast, primarily at Pas-de-Calais. This work was assigned to the "Organisation Todt" and commenced on 22 July 1940.