The invasion of Normandy was another monumental battle in history that got the Hollywood treatment. "The Longest Day" is a three-hour-long epic that attempts to chronicle the historical facts and personal experiences of the battle. Producer Darryl Zanuck based his 1962 film on a thoroughly researched book of the same name by Cornelius Ryan.
Historian Stephen E. Ambrose wrote that the filmmakers were "tremendously successful" in "recreating the spectacle of the June 6 invasion." Zanuck used military advisers on set, but, Ambrose points out, he didn't always heed their advice. Zanuck opted for theatrics over historical accuracy in many key points.
On the other hand, a few scenes seem too far-fetched to be true, but they were. For instance, one paratrooper in the film gets caught on a church steeple and must watch the horror of the battle. In reality, it was a far more dramatic scene: Two paratroopers were caught on the roof, and a German soldier was about to shoot them when a dying soldier on the ground shot and killed him just in time. In another instance, critics didn't appreciate that the film depicted the German High Command as "fumbling." Ambrose praises this as "one of the most accurate parts of the film" [source: Ambrose]. Indeed, Ambrose also praises how Zanuck portrays Germans as sympathetic.
One criticism Ambrose has, however, is the lack of realistic violence. For that, we suggest you look to "Saving Private Ryan," which depicts a fictional narrative but portrays a much bloodier invasion of Normandy.