5. 'The Day the Earth Stood Still'
When a human-like alien named Klaatu lands his flying saucer in Washington, D.C., he merely wants to teach mankind about peace, but a nervous soldier takes a shot at him and everyone else assumes his intentions are terrible. He eventually poses as a man named "Mr. Carpenter" and learns about man's endless capacity for war and destruction. The Cold War overtones are impossible to ignore, as does the fact that the alien's Earth name is the same as the profession of another guy who preached peace about 2,000 years ago. The film ends with a stark warning that earth will be destroyed should they keep up their war-like ways.