The best 1950s monster movies were Cold War movies.

The Day the Earth Stood Still (1951): a visitor from another planet lands a saucer in Washington. His message is that Earth can keep its wars at home, but if it carries them into space it will be destroyed.

Them! (1954): giant ants come out of the New Mexico desert near where the first atomic bomb was tested. Radiation made them, and the scientists warn they may not be the last.

Invasion of the Body Snatchers (1956): a small California town is quietly replaced by calm, identical copies of its own people.

Critics still argue whether the pods stood for the communists or for the people hunting them.