Factual error: It is barely credible that a young Victorian woman like Elena would even think about wearing a goatskin miniskirt - exposing her legs in those days would be akin to walking about topless nowadays. Even if she did those bright yellow cotton knickers - gleefully visible in the scene in the beehive - are in no way from the 1860s. Her pants are a hundred years ahead of their time.
Plot hole: Maria describes in lurid detail how Anna was arrested by the Germans and tortured by being severely whipped, leaving her with gruesome scars all over her back. She also says that Anna hasn't spoken a word to anyone since she escaped from captivity. How, then, does Maria (or anyone else) know about the scars? Nobody saw them (they don't exist) and Anna obviously didn't tell anyone about them.
Visible crew/equipment: On the beach there's a battle charge, and in the foreground you can clearly see a set of tyre tracks from the camera vehicle preceding the charge.
Revealing mistake: During several of the driving sequences, the teenager in the driver's seat turns the steering wheel - but the rear screen projection keeps the car "moving" in a straight line. And it's particularly ironic in light of the movie's "big message" that the students here bear no resemblance to real-life teenagers in any real school. They're all slim, trim, athletic and model-gorgeous, as well as all-too-obviously not teenagers at all. (Because US child labor laws severely restrict the hours that underage actors can work, many films "cheat" by having youthful 20-somethings play the teens.)
Continuity mistake: When Sam Twist jumps from the train on the Forth Bridge, he lands in a puddle between the tracks, which are resting on sleepers on top of ballast - but when we see the train disappearing, there are no sleepers or ballast - the rails look like they're on concrete 'runners'. (00:55:00)
Visible crew/equipment: During the scene when Cliff's girlfriend is walking down a street singing, if you look carefully there is a gap between two of the buildings through which you can see the scaffolding holding the set up.
Factual error: With the radiation belt on fire, the icecaps begin to melt. The Seaview is bombarded by huge chucks of ice. The ice is sinking to the bottom like stones. Ice floats, it doesn't sink.
Continuity mistake: When the twins are in the cabin and Sharon offers Susan a Fig Newton, the cookies are is a jumble in the box. A moment later, the cookies are in a clean row.
Continuity mistake: At the beginning of their first pool match, Fats' collar goes from buttoned to loose, to back buttoned in only a moment on-screen.
Revealing mistake: At the opening of the film as the pirate ship passes left to right the flags are blowing in the opposite direction of the ship's movement and the sails keep blowing back although the ship keeps moving forward. Notice the large amount of churning water at the ship's rudder indicating that the boat is powered by a motor.
Other mistake: When they're roping the mustangs, the "stallion" doesn't have the genitals of a stallion.
Continuity mistake: The police that come to the aid of the professor are driving an older Ford when they approach than when they arrive to help. The car is a newer model in the later scene.