Merville Battery was a coastal fortification built by the Nazis in Merville-Franceville as part of the Atlantic Wall during World War II. Because this particular battery was much more better fortified than other similar installations, it was one of the first to be attacked by the Allies on D-Day.
Indeed, it was successfully captured by British paratroopers on June 6, 1944, because they mistakenly believed the battery contained heavy-caliber weapons that could threaten the nearby beach landings. They discovered, however, that what it contained, essentially, was inoffensive World War I vintage guns. The battery also comprised four six-foot-thick, steel-reinforced concrete gun casemates, designed to protect mountain guns, as well as a command bunker, dorms and ammunition magazines. After the British left the battery to liberate a nearby village, Merville was once again taken over by the Germans until they withdrew France in the following month of August.