Trivia: Steven Spielberg saw this film when he was a child and was fascinated by the Martians. He later based E.T. from E.T. the Extra-Terrestrial (1982) on them.
Trivia: According to the bonus material on the DVD, the monster was used as an after thought. The director and writer thought the audience's imagination would suffice, but the higher-ups at Universal felt otherwise.
Trivia: Even though the film was made in 3-D, director Andre de Toth could not see the effect as he was blind in one eye.
Trivia: The film was given an "X" certificate in Britain, although it was later played on children's television.