Factual error: The picture of Eddie and Teddy on the road with dad, supposedly taken in 1906, shows a Ringling Bros and Barnum & Bailey circus poster. In 1906, the Ringling Brothers circus and the Barnum & Bailey circus were two separate circuses playing in different parts of the country. They did not combine the two shows until 1919. (00:27:00)
Factual error: At the end, when Cyndi Lauper touches the glowing pyramid, goes into a trance, and starts translating the inscription, Jeff Goldblum pulls her off and she doesn't finish it. One of the bad guys says that what Cyndi already said will be enough to help him decode the rest and that it's just a matter of "cartography" now. He should have said "cryptography" (skill of decoding secret writings) and not "cartography" (which has to do with making maps).
Factual error: When Bruce and Patricia are in a lift after being chased by the cars in the garage, the lift rapidly descends but the two people in the lift are seen struggling on the floor when they should just about be on the ceiling due to the speed of the lift's descent.
Factual error: Slater had close to a dozen sticks of dynamite on him. At the very least they should have knocked Winona Ryder down, and made her deaf for a few days.
Factual error: Sean Connery's character is the Provost Marshall for the Presidio, he would not be wearing the MP sleeve placard as he is in the scene at the Officer's Club. He also wouldn't be running around wearing a Field Jacket with the collar up and it unzipped. You wear the jacket correctly or not at all.
Factual error: Shooting at a gas tank with buck shot at 50 meters distance will not make it explode (it likely won't even dent the surface), and lead pellets do not cause sparks when they hit.
Factual error: Radium Chloride (stated by the doctor to be the ingested poison) does have a slightly luminous glow to it, but absolutely doesn't have the intense shining bright green luminous glow that is shown at the end of the film in Professor Cornell's mug.
Factual error: Right after the movie shows us a sign telling us that we are in NJ in 1937, here you have Ginevra Boynton reading the March 1938 issue of Daring Detective, which even plays a larger role in the story later. (00:00:35)