While clearing a section of the Normandy beach near Pointe du Hoc, the crew unearthed a tank that had been buried in the sand since the original invasion. Mechanics cleaned it off, fixed it up and it was used in the movie as part of the British tank regiment.
During the filming of the landings at Omaha Beach, the extras appearing as American soldiers didn't want to jump off the landing craft into the water because they thought it would be too cold. Robert Mitchum (Gen. Norm Cota) was so disgusted with them that he jumped in first, at which point, the soldiers had no choice but to follow his example.
Henry Grace was not an actor when cast as Dwight D. Eisenhower, but his remarkable resemblance to Eisenhower got him the role.
Sean Connery asked that his scenes be filmed quickly so he could get to Jamaica in time to star in Dr. No (1962).
An estimated 23,000 troops were supplied by the US, Britain and France for filming (Germans only appeared as officers in speaking roles). The French contributed 1000 commandos, despite their involvement in the Algerian War at the time.