20,000 Leagues Under the Sea (1954)

Factual error: The giant squid's tentacles aren't shaped like ones in the real world are.

Revealing mistake: In the scene near the end when water is filling up the submarine, Kirk Douglas begins fighting with a member of the crew to escape. As Douglas hits him his false sideburn falls off and flies across the screen.

Audio problem: During the "Whale of a Tail" scene, there are several instances when Kirk Douglas' hands are away from the guitar strings, to ring the bell or twirl the guitar, yet the sound of the guitar strumming continues without missing a beat.

Trivia: The name of the supply colony that Nemo shows the professor is Rura Penthe, which is also the name of the Klingon prison in Star Trek VI.

Captain Nemo: Think of it. On the surface there is hunger and fear. Men still exercise unjust laws. They fight, tear one another to pieces. A mere few feet beneath the waves their reign ceases, their evil drowns. Here on the ocean floor is the only independence. Here I am free! Imagine what would happen if they controlled machines such as this submarine boat. Far better that they think there's a monster and hunt me with harpoons.

Captain Nemo: Mr. Land, you saved my life. Why?
Ned Land: That's a good question. Well, there's only one thing a fella can do when he's made a mistake as big as this.
Conseil: What?
Ned Land: Get drunk.

Captain Nemo: The natives over there are cannibals. They eat liars with the same enthusiasm as they eat honest men.