You'll never be able to watch these movies the same way again.
Some very famous films contain some very obvious mistakes that have been picked up by eagle-eyed viewers over the years.
Here are seven of our favourite examples:
During a battle in the Colosseum, a horse drawn chariot flips over onto its side and if you look closely, you can see a gas cylinder in the back of the chariot.
FYI - The movie is set in 180AD and stainless steel gas cylinders weren't invented until the 1800s.
There's a scene in the Clint Eastwood directed film where Bradley Cooper's character tries to soothe his baby.
But it's glaringly obvious that the baby is a plastic doll.
In a since deleted tweet, one of the producers explained, "Hate to ruin the fun but real baby #1 showed up with a fever. Real baby #2 was no show".
In Quentin Tarantino's classic, there's a scene where Vincent and Jules get caught off guard by a man with a gun who fires six shots at the duo but fails to hit them.
But there's a small problem.
If you rewind to before the guy started shooting, you can notice that the bullet holes were already in the wall.
What has more horsepower than William Wallace and his merry men? A car.
Yep, as Mel Gibson's character leads his men into battle on horseback a car can be seen in the background of the shot.
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It may have been nominated for a Best Picture Oscar but it's not exactly the most accurate.
Despite being set in the 1980s, Ron Woodroof (played by Matthew McConaughey) has a poster of a Lamborghini Aventador on the wall in his makeshift office.
That certain car wasn't actually released until 2011. Oops.
Sylvester Stallone went off-script in his 1986 film and ripped another guy's white singlet.
The rip exposed a microphone which was strapped to the other actor's chest with gaffer tape.
Either the director didn't notice or didn't care, because the mistake was left in the final edit.
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There's a scene in Alfred Hitchcock's 1959 movie where a female character shoots a gun in a packed restaurant.
The set is filled with extras, including one young fella who obviously wasn't a fan of loud noises.
Before the gun is fired, the boy can be seen in the background putting his fingers in his ears.
Check out the scene below and keep an eye out for the kid in the blue jacket: Small mistake