The Heroes of Telemark (1965)

Factual error: The daylight air-raid on the Norwegian Heavy Water plant in 1942 was done by Boeing B17G bombers, with the distinctive chin gun turrets. These planes did not come into service until 1944, when they were introduced to counter the head-on attacks by German fighters.

Continuity mistake: In the scene when Richard Harris and Kirk Douglas parachute back into Norway, there is a white parachute blowing in the wind. Kirk Douglas goes to collect it, but there are footprints already in the snow where they have previously filmed a retake. (00:27:00)

Plot hole: When Knut and Rolf are setting the bombs in the engine room of the Hydro ferry, they are interrupted by a German soldier who they quickly overpower and kill. Why don't the Germans then notice that this soldier is missing? The clocks attached to the bombs show the time around 01:35am when the soldier is killed yet the alarm still hasn't been raised when Rolf catches the ferry several hours later at 9am. This is far too long for any soldier to be on sentry duty without reporting in to the Guardroom. The Germans would have known that the soldier was on duty on the ferry and when he didn't report in then they would have searched the boat thoroughly and found the bombs. (01:51:30)