6. 'Forbidden Planet'
Long before 2001: A Space Odyssey, Star Wars or Star Trek, there was Forbidden Planet. The 1956 classic is the story of a starship in the 23rd century that travels to a distant planet to figure out what happened to a crew that landed there two decades in the past. They find two survivors, a robot named Robby and layers upon layers of secrets when they arrive. Leslie Nielsen took on one of the lead role about a quarter century before Airplane made him a comedy icon.