Revealing mistake: It is not what is seen here that is the problem, but what we don't see on the Hogwarts Express; first on the way to Hogwarts when Harry, Ron, and Hermione are in their compartment talking about Draco, and second, during holiday break, when Harry and Ron are talking about Unbreakable Vows. As the camera faces the large compartment window, we see the scenery out the window, but as the train speeds along, the scenic reflection of the windows opposite it, in the corridor, should be seen but isn't. What is reflected is the light colored wall of the compartment beneath the blacked-out window. The camera filming the shots from this angle is positioned at that window, and to hide the camera/crews' outline, the window was covered.
Revealing mistake: When John is stuck in traffic and he walks up to the other man asking if anyone was hurt, the guy looks behind John's shoulder as if the plane is coming right behind him. Then John turns around and looks right behind him as well. But the camera then pans all the way to the side to see the plane coming in before it crashes - they were looking in the wrong place.
Revealing mistake: The film is set in 1891. After Holmes escapes from Parliament, Thomas Thornycroft's statue of Boadicea on the Thames Embankment next to Westminster Bridge can be seen, even though it was not completed until 1905. (01:35:45)
Revealing mistake: When Langdon and Victoria walk towards the Pantheon, the first two angles show them walking alone with some stunt-women behind. But in the third angle, a couple of seconds later, a huge line of people appears, lining perfectly in the back, watching the camera. Obviously a group of real tourists standing behind a security line watching the shooting.
Revealing mistake: When William is running at the end, there is already a blood trail on the floor. Clearly from another take. (01:15:10)
Revealing mistake: During crash scenes towards the end the local traffic in the background is driving on the left hand side of the road (filmed at Darling Point, Wynnum, Australia) even though the movie is set in the USA.
Revealing mistake: During the fight scene at the rest area, Gina is hitting Dick, and her sweater rides up her back, revealing the battery pack for the microphone taped to the small of her back.
Revealing mistake: When the soldier is tempering, you can see sparks fly before the hammer hits the metal.
Revealing mistake: In the scenes where Sam 1 and Sam 2 are in touch, the double is completely wrong. Wrong hair, wrong profile and wrong hind end.
Revealing mistake: In the scene at the Pope's apartment, when Clouseau enters the balcony for the second time to "look at the moon", there is a third shot from his back when he is leaning out of the balcony. You can see a platform which supposedly was there to help him easily fall out. (00:54:35)
Revealing mistake: When both Lisbeth and Mikael open their Apple Mac computers and use them, the little apples on the outside should light up, but they don't - neither computer does; they're switched off or not powered up - Mikael even goes to the trouble of connecting his to a power cord.