History Film / TheDayTheEarthStoodStill1951

* AllNationsAreSuperPowers: Surprisingly averted. Klaatu landed in Washington, D.C. because he thought that landing in the capital of the world's most powerful country would get the ''entire'' world's attention, but he repeatedly insists that his message is for all of humanity, no matter how large or small the country. He brushes off U.S. warnings about the Soviets as internal bickering that doesn't concern him. Moreover, when it is suggested that he could give his message to the whole world by addressing the United Nations, he actually ''declines'' once he learns that not every nation or state-group is represented by it (when the film was made, the People's Republic of China was an unrecognized state, and would not be until 1971, when it replaced Taiwan - but then Taiwan wasn't represented). Ultimately, pressed for time he comes up with the impromptu solution of addressing an international conference of scientists, who are generally apolitical.

* [[SciFiWritersHave/NoSenseOfDistance Sci-Fi Writers Have No Sense Of Distance]]: Klaatu claims to have arrived from a planet "250 million miles" from Earth. This would place his homeworld somewhere in the Sun's asteroid belt.
** While this is correct, it's worth noting that this movie came out in 1951, 6 years before Sputnik - the first satellite - was launched. At this point in history, people simply didn't yet know that Venus was impossibly hot and Mars was a barren desert of craters and rocks - so at the time both planets were reasonable places to speculate about having life.

* BrokenAesop: The intended message is HumansAreTheRealMonsters because Klaatu is a peaceful ambassador whose home planet fears Earth will expand into outer space due to its advances in space and nuclear technology, makes the Earth stand still to deliver a message of peace, which culminates in Klaatu's accidental death. Except, Klaatu arrives with zero warning, shuts down all power on Earth (except in situations that would cause deaths, like hospitals and planes in flight) all to deliver a message of complete annihilation if they do anything remotely "threatening" to a planet ''they didn't even know existed'' solely because Earth has the ''theoretical'' capability to attack them, not because of any action Earth intentionally or unintentionally made against them. This could be seen as making Klaatu's planet being extremely hostile and xenophobic, complicating the film's intended message.

* EinsteinHair: Professor Barnhardt, who's clearly a NoCelebritiesWereHarmed version of Einstein.

* TropeMakers: UFO skeptics have cited similarities between this movie's plot and the claimed encounter of [[https://en.wikipedia.org/wiki/George_Adamski George Adamski]] with the alien Orthon in California in 1952, which started the "genre" of peaceful alien contacts popular in TheSixties and TheSeventies, before the AlienAbduction completely replaced them.

* TropeMakers: It's been pointed that there are uncanny similarities between this movie's plot and the supposed encounter of [[https://en.wikipedia.org/wiki/George_Adamski George Adamski]] with the alien visitor Orthon in California in 1952, which started the "genre" of peaceful alien encounters before the AlienAbduction replaced them.

* RiddleForTheAges: Klaatu tells Helen that if he is killed, Gort will destroy the Earth, and to stop him, she must use the code word "Klaatu Barada Nikto". She successfully does so, but exactly what the phrase means (obviously, it's something in Klatuu's language) has never been truly revealed. Creator/RobertWise, related a story he had with Edmund North, the screenplay writer, saying North told him, "Well, it's just something I kind of cooked up. I thought it sounded good." On the other hand, Billy Gray, who played Bobby Benson in the film, said that "barada nikto must mean... save earth". Florence Blaustein, widow of the producer Julian Blaustein, said North had to pass a street called Baroda every day going to work and said, "I think that's how that was born." Film historian Stephan Jay Rubin claimed that in an interview he had with North when he asked the question, "What is the direct translation of Klaatu barada nikto, and Edmund North said to me 'There's hope for earth, if the scientists can be reached'."

* HideYourOtherness: Klaatu spends a good chunk of the film hiding from the military by posing as a man named Mister Carpenter who's renting a room in a boardinghouse; he soon becomes trusting enough of the family to let them in on his secret and elicit their help in getting back to his ship and preventing The End of the World as We Know It.

* HumansAreTheRealMonsters: Klaatu shows up and tries to give humanity a machine that would allow for interstellar communication. And how do the humans respond? ''By shooting him''. After he recovers he spends some time observing humanity and eventually decides to show he means business by disabling all electrical technology on the planet (with a few exceptions that could result in death, he leaves alone planes in flight, hospitals, and the like) for a short period of time. Then the humans shoot him ''again'', this time killing him. He gets better, scolds them for being so violent, and essentially says that if humanity keeps this up the interstellar community will have no choice to put them down in order to prevent humanity from carrying its warlike ways out into space.

* MessianicArchetype: Klaatu is an AllLovingHero who comes from the heavens to save humanity, meets resistance from people not prepared to listen to his message, is killed, is resurrected, gives his last message, and returns to the heavens.

** The ominous scene when Klaatu walks with a bag on the street in front of Helen's pension may have inspired the iconic post of ''Film/TheExorcist''.
** When Helen tells Tom that Klaatu/Mr. Carpenter is not a menace and must be left alone, he gets deadset into having the alien killed, out of pure jealousy, no matter if other people may die. Decades later, a similar scene happened into a [[WesternAnimation/BeautyAndTheBeast certain Disney film]].

** While this is correct, it's worth noting that this movie came out in 1951, 6 years before Sputnik - the first satellite - was launched. At this point in history people simply didn't yet know that Venus was impossibly hot and Mars was a barren desert of craters and rocks - so at the time both planets were reasonable places to speculate about having life.

* SpacePolice: Gort and Klaatu. In a twist, Gort turns out to be the officer, and Klaatu is his assistant. In the short story on which the movie is based, Klaatu is only an artificial construct created to make it possible for Gort to communicate with humans

* SparedByTheAdaptation: Although Klaatu dies in both the original story, "Farewell to the Master", and in this film, he lasts longer in the film and specifically survives the event that killed him in the original. The story had Klaatu dying immediately after arriving on Earth (he only gets as far as introducing himself and Gort before he's shot by a fanatic with a gun). In this film, although he is shot while introducing himself, it's not fatal and he quickly recovers, but dies at the end of the film after being shot again during the manhunt. The screenwriter had intended for him to survive the film, too, being revived at the end by his alien technology, but the studio found the idea of technology alone being able to bring someone back from the dead too controversial; in the final film, although Klaatu is revived long enough to deliver a final message, he states explicitly that it's temporary and that true resurrection is "reserved for the Almighty Spirit".

* SwordOfDamocles: Klaatu claims that this is why his people built Gort and other robots like him; the robots were purposely programmed to destroy any planet, including Klaatu's, if interplanetary war ever started, preventing their worlds from ever doing so.
* ThatWasTheReward: At the beginning of the movie, after Klaatu gets out of his saucer he approaches the U.S. Army soldiers surrounding it. He offers a device that suddenly juts out spines and a soldier panics and shoots the device. Klaatu later explains its true nature.