Which 1951 science fiction film features an alien named Klaatu and his robot Gort?

Which 1951 science fiction film features an alien named Klaatu and his robot Gort? The Day the Earth Stood Still is the film. Directed by Robert Wise for 20th Century Fox, it opens with Klaatu arriving in Washington, D.C., in a flying saucer accompanied by Gort, a powerful humanoid robot.

Klaatu comes with a warning for Earth’s leaders: humanity’s atomic weapons and aggressive behavior threaten the wider interplanetary community. After he is shot by a nervous soldier, Gort disables nearby military equipment, establishing that the robot is both guardian and deterrent. Klaatu later adopts the alias “Mr. Carpenter” while trying to understand human society.

The film reflects early Cold War anxiety and the Atomic Age, using extraterrestrial diplomacy to discuss nuclear conflict. Its famous command, “Klaatu barada nikto,” is spoken to stop Gort. The 1951 original is often confused with the 2008 remake, but Michael Rennie played Klaatu and Lock Martin portrayed Gort in this version.