Warning: Wikipedia contains spoilers.
Instead of walking tripods, the movie presents the Martian war machines as sleek, sinister-looking airships that float above the ground. Combined with outstanding special effects that hold up well even when viewed over fifty years after the movie was made, the movie is a visual feast, and one of the few science fiction films that do not talk down to the audience. It was one of few science films to show a full-fledged invasion by an extraterrestrial army, and World War II stock footage was skillfully used to present the illusion of a worldwide invasion, with armies of all nations joining together to fight the invaders.
Wells used the second half of his novel to make a satirical commentary on civilization and the class struggle. Pal did not write the satire into the movie, though he did add a religious theme to the film, which would probably have annoyed the atheistic Wells.
The movie starred Gene Barry as Dr. Clayton Forrester (whose name was also used in the Mystery Science Theater 3000 TV series as a homage to the film), Ann Robinson as Sylvia Van Buren, and Les Tremayne as Major General Mann. The voiceover commentary was by Sir Cedric Hardwicke. Haskin, the director, was a veteran of television who directed episodes of a number of TV series, including several episodes of The Outer Limits.
Other movies related to The War of the Worlds include:
Independence Day (1996), directed by Roland Emmerich. The aliens (not from Mars) apparently never heard of computer security, and used Earth satellites for their communication system. They were defeated by the plucky heroes installing a computer virus onto one of the motherships.
Mars Attacks (1996), directed by Tim Burton. A more humorous treatment, and very loosely based upon the original story. The title comes from a series of bubble-gum cards issued in the 1950s; the appearance of the Martians in the cards and in the film appears to be derived from the 'mutant' in the film This Island Earth. In this version, the aliens are repelled not by the natural germs on Earth, but by Slim Whitman's yodelling which causes their heads to explode.