Gone With The Wind (1939) - 6 major mistakes

Factual error: Scarlett is seen walking on the main street on the way to the hospital. You can clearly see a light bulb in one of the street lights.

Continuity: In the scene where Scarlett is talking to Ashley about owing the carpet bagger 300 dollars right before Ashley kisses her you can see a definite change. Ashley has different dirt on his face and Scarlett's dress looks lighter. Her hair is also loose in different places.

Factual error: In the scene where Ashley is brought back wounded from the raid where Scarlett's husband Mr Kennedy was killed, Melanie grabs a lamp to follow the man carrying Ashley to the bedroom and you can see an electrical cord hanging down from it.

Continuity: The shadow scene in which Scarlett and Melanie care for the wounded in the Atlanta hospital was filmed with two doubles. Since Leigh and de Havilland were standing at the wrong angle to cast the shadows, two stand-ins were positioned in front of the high-intensity light. The shadows of the doubles were reflected on the wall behind the stars, and the result was a stunning visual effect. Yet upon a closer look, the gestures of the stand-ins are not totally synchronised with the movements of the stars.

Continuity: When Scarlett is attacked in the woods on a bridge while on her way to the lumber mill the buggy very nearly goes off of the bridge backwards. Then Scarlett faints, but when the camera returns to the full shot of the buggy, suddenly it is squarely in the middle of the bridge and in no danger at all of falling over the edge.

Continuity: In the scene showing guests arriving at the Wilkes' barbecue, you see buggies and carriages driving through the front gates and up the drive toward the Wilkes' home. The carriages clearly create shadows on the ground, but not on the stone pillars of the gates. This is because when the movie was filmed, there were no actual gates. The gates were later "painted" into the frame.  Proving someone forgot to "paint" shadows onto the pillars.