the day the earth stood still
The Day the Earth Stood Still is a 1951 American science fiction film from 20th Century Fox, produced by Julian Blaustein and directed by Robert Wise. Set in the Cold War during the early stages of the nuclear arms race, the storyline involves a humanoid alien visitor who comes to Earth, accompanied by a powerful robot, to deliver an important message that will affect the entire human race.
The newer adaptation of the same name was released in 2008.