* AllStarCast: If you were an A-List male actor in Hollywood in 1962, you have at least a bit part in this film. Plus a couple well-known British, French and German actors.
* ArtisticLicenseHistory: Engineers are seen removing explosives from the Orne Bridge. In reality they hadn't been placed in their slots when the gliders landed. Zanuck chose to ignore Howard's telling him this for the sake of drama.
** Averted when a scene where German soldiers are seen running out of the café near that bridge wasn't shot, as one of the owners insisted vehemently she had never allowed Germans to sleep there.
* AsHimself:
** Almost. Actor Richard Todd plays John Howard, the Major whose unit secures Pegasus Bridge. One of the relief units coming to their aid was led by Captain Richard Todd!
** Played straight with Joseph Lowe, one of the cliff climbers at Utah Beach who reprised his efforts for the movie.
** Also played straight by Bill Millin, the bagpiper with Lord Lovat's commandos.
* BackedByThePentagon: About 23.000(!) real US, British and French soldiers were used as extras in the movie. They also rented two Messerschmitts from the Spanish air force and four Spitfires from the Belgian air force.
* CastTheExpert: Richard Todd, who plays Major Howard of the British Airborne, was a British paratrooper during the war and actually took part in the D-Day landings -- in fact, he was initially approached to play ''himself'' in the film.
* DawsonCasting: John Wayne as Lieutenant Colonel Benjamin Vandervoort. The real Benjamin Vandervoort was 12 years younger than Wayne, and on D-Day he had been just 27, while Wayne was '''54''' when the movie was filmed.
* DirectorDisplacement: Given ''five'' people did the thing simultaneously, doesn't surprise producer Darryl F. Zanuck gets more focus than all of them.
* HeyItsThatGuy:
** Besides the ones mentioned below, there's Red Buttons, John Wayne, Robert Mitchum, Eddie Albert, Paul Anka, Fabian, Robert Wagner, Richard Dawson...
** Also cartoonist and comedian Creator/{{Loriot}} in an uncredited bit part as a German staff officer.
** Two German actors were future ''Film/JamesBond'' villains:
*** Gert Fröbe -- best known for playing the title role in ''Film/{{Goldfinger}}'' -- as the German sergeant [[KnownOnlyByTheirNickname "Kaffeekanne"]] (coffee-pot), who rides his horse to the beach every morning to bring coffee to the troops.
*** Curd Jürgens (credited here as Curt Jürgens) -- who played Karl Stromberg in ''Film/TheSpyWhoLovedMe'' -- as Major General Günther Blumentritt.
*** The first Film/JamesBond himself, Sean Connery, is one of the British soldiers landing on Sword beach.
** Wolfgang Preiss as General Pemsel. He became almost ubiquitous in WWII films, appearing in ''The Train'', ''Film/VonRyansExpress'', ''Film/IsParisBurning'', ''Film/ABridgeTooFar'' and ''[[Literature/TheWindsOfWarAndWarAndRemembrance The Winds of War]]'', among others. Of course, European audiences at the time probably recognized Preiss as [[Film/Die1000AugenDesDrMabuse Dr. Mabuse]].
** André Bourvil playing the Mayor of Colleville. Bourvil was a popular French comedy star, though he occasionally [[PlayingAgainstType played against type]] in dramatic roles. International viewers might recognize him best from ''Film/TheRedCircle''.
** Austrian actor Dietmar Schönherr, best known as Major [=McLane=] from ''Series/{{Raumpatrouille}}'', has a small part as a Luftwaffe major.
* RealLifeWritesThePlot:
** Roddy [=McDowall=] asked for a small role to spare his boredom after ''Film/{{Cleopatra}}'' was delayed... AGAIN.
** Creator/SeanConnery, on the other hand, also has a small role because he was eager to get off to Jamaica and begin filming ''Film/DrNo''.
* RetroactiveRecognition: Before he became famous, Creator/{{Loriot}} got cast by Bernhard Wicki in an uncredited bit-part as a junior Wehrmacht staff officer.
* ScrewedByTheNetwork: Averted - Fox was planning on just doing a quick wide release to earn some cash they needed to offset their losses from ''Film/{{Cleopatra}}''. Darryl Zanuck threatened to bring''The Longest Day'' to Warner Bros. if they didn't do a proper roadshow release, and Fox had to comply. (it still was the box office hit the studio needed)
* ThrowItIn: While clearing a section of the Normandy beach near Pointe du Hoc, the film crew found a tank used in the invasion. They cleaned it up and used it for the British Invasion scenes.
* WhatCouldHaveBeen:
** Creator/ChristopherLee, who fought in the War as an intelligence officer with the RAF, auditioned for any role he could get. He was turned down because the producers felt [[{{Irony}} he didn't look like a military officer]].
** This was made just after UsefulNotes/DwightDEisenhower's presidency and the producers very nearly '''cast Eisenhower to play himself'''. They abandoned the idea because he was too old, though.

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