American military planes and ships; tank barriers along Siegfried Line; French artillery along Maginot Line; French soldiers at switchboards

US military planes flying above ocean dotted with ships / looking down at plane flying over ship / ships on sea seen from moving ship / row of ships / various shots rows of vertical steel tank barriers along France's Maginot Line / workers digging ground next to rows of concrete tank barriers along Germany's Siegfried Line / MS barriers / French howitzer planted on Maginot Line / row of planted howitzers, narration in French / German soldiers pushing artillery gun uphill / French soldiers in switchboard area / MS soldier wearing headphones and writing on chalkboard / soldiers at switchboard / CU soldier / soldiers in switchboard room / CU German soldier looking intently through scope / rows of concrete tank barriers along Siegfried Line / LS barriers / Note: exact month/day not known