The DVD of "Day the Earth Stood Still" has some interesting fun-filled facts among the "extras." One of them is that Gort the robot was played by Lock Martin, 7'7" tall, who made a living doing novelty appearances at Knott's Berry Farm, as a doorman at Grauman's Chinese Theater, etc. They explained that people with abnormalities that make them grow that tall are actually weaker than average folks. So, in the scene where Gort is carrying Patricia Neal into the flying saucer, you can actually see wires leading from his shoulders to his forearms to help him bear the load.
It's one of my faves--a truly intelligent, thoughtful film. Hugh Marlowe, Eternal Smarm, went on to play an even smarmier character in "Seven Days in May," one of Frankenheimer's best.
"Klaatu Barata Nikto!"