History Trivia / DestroyAllMonsters

** Film was intended to be the Main/GrandFinale of Showa Era and even Entire Series in general, but series continued with Film/AllMonstersAttack the next year.

** ''Destroy All Monsters'' was intended to be the GrandFinale to the Godzilla series (hench why Toho wanted ''every'' Kaiju that they had owned up to this point to appear), but plans soon changed when Toho saw how popular this movie was at the box office, especially amongst children, and proceeded to make 6 more movies in the Showa era.

* WhatCouldHaveBeen: The monster selection of the film was intended to be far larger than in the final film. Originally the original plan was to show all of Toho's Kaiju in one film together (including all of the ones who seemingly died in their previous entries, such as Dogora (killed by the JSDF in it's [[Film/{{Dogora}} debut film]]) Frankenstein (who drowned in ''Film/FrankensteinConquersTheWorld''), the Gargantuas (burnt to death by a combination of napalm and a volcanic eruption in ''Film/WarOfTheGargantuas''), the Giant Condor (killed by Godzilla in ''Film/EbirahHorrorOfTheDeep''), Kamacuras (also killed by Godzilla while they were attempting to eat the egg containing his son in ''Film/SonOfGodzilla'') and even Oodako (who drowned alongside Frankenstein), Kaiju such as [[Film/{{Gorath}} Maguma]] and [[Film/EbirahHorrorOfTheDeep Ebirah]] were to be in the film, and Maguma and Baragon were to act as guardians to the Kilaaks in fending off the SDF. However, due to the frail conditions of the suits owing to constant modifications and use in ''Series/{{Ultraman}}'', Anguirus, Gorosaurus, and Minya were substituted instead. Baragon did appear several times in the movie, but Maguma was cut altogether.

** Maguma was ultimately removed, not because of suit condition, but because in his film of origin, ''Film/{{Gorath}}'', the moon is destroyed in 1980, the year the story is set. However, in this film set in 1999, the moon plays a prominent part of the story, meaning that it was meant to be a different Maguma altogether.

* AccidentallyCorrectZoology: [[PteroSoarer Rodan]] is shown diving into the water to catch dolphins, at the time when pterosaurs were thought to avoid getting themselves wet or else it would render them unable to fly. Recent fossil evidence seems to indicate that real ''Pteranodons'' would hunt this way as well.

** Haruo Nakajima originally pitched for Godzilla to do his iconic dance from ''Film/InvasionOfAstroMonster'' as his victory dance after killing off King Ghidorah but Toho politely rejected it.

** Film/KingKong was in early drafts of the film, but ended up getting cut as the expiration of Toho's license to use the character was coming too close to production time for comfort. Just imagine seeing Godzilla, Rodan, Mothra, Anguirus, Kumonga and the ''Eighth Wonder of the World'' himself (including the very Kaiju Kong himself beat in his last film in Gorosaurus), all fighting against King Ghidorah together, also ''Mechani-Kong'' was planned to appear as well likely as a possible guard on Monsterland and later on under the Kilaak's control, but was also cut for the same reasons as King Kong (despite the fact Toho actually owns ''Mechani-Kong's'' rights, the same rights issue would also keep him out of what ended up being ''Film/GodzillVSKingGhidorah'').

* WhatCouldHaveBeen: The monster selection of the film was intended to be far larger than in the final film. Originally the original plan was to show all of Toho's Kaiju in one film together (including all of the ones who seemingly died in their previous entries, such as Frankenstein (who drowned in ''Film/FrankensteinConquersTheWorld''), the Gargantuas (burnt to death by a combination of napalm and a volcanic eruption in ''Film/WarOfTheGargantuas''), the Giant Condor (killed by Godzilla in ''Film/EbirahHorrorOfTheDeep''), Kamacuras (also killed by Godzilla while they were attempting to eat the egg containing his son in ''Film/SonOfGodzilla'') and even Oodako (who drowned alongside Frankenstein), Kaiju such as [[Film/{{Gorath}} Maguma]] and [[Film/EbirahHorrorOfTheDeep Ebirah]] were to be in the film, and Maguma and Baragon were to act as guardians to the Kilaaks in fending off the SDF. However, due to the frail conditions of the suits owing to constant modifications and use in ''Series/{{Ultraman}}'', Anguirus, Gorosaurus, and Minya were substituted instead. Baragon did appear several times in the movie, but Maguma was cut altogether.

** Film/KingKong was in early drafts of the film, but ended up getting cut as the expiration of Toho's license to use the character was coming too close to production time for comfort. Just imagine seeing Godzilla, Rodan, Mothra, Anguirus, Kumonga and the ''Eighth Wonder of the World'' himself (including the very Kaiju Kong himself beat in his last film in Gorosaurus), all fighting against King Ghidorah together, also ''Mechani-Kong'' was planned to appear as well likely as a possible guard on Monsterland and later on under the Kilaak's control.

** Film/KingKong was in early drafts of the film, but ended up getting cut as the expiration of Toho's license to use the character was coming too close to production time for comfort. Just imagine seeing Godzilla, Rodan, Mothra, Anguirus, Kumonga and the ''Eighth Wonder of the World'' himself (including the very Kaiju Kong himself beat in his last film in Gorosaurus), all fighting against King Ghidorah together, also ''Mechani-Kong'' was planned to appear as well likely as a possible guard on Monsterland and later on under the Kilaaks control.
** The Gargantuas, Sanda and Gaira were also intended to be included in the film, but were cut as well, even their father ''Frankenstein'' was also intended to show up at some point.
** In addition to the above monsters, Toho was also going to include ''hybrid'' Kaiju as well (such as a Godzilla-Mothra hybrid, and many others), likely as a result of inbreeding amongst the populace. This idea was quickly dropped due to the {{Squick}} factor of seeing such actions between Kaiju.

* RecycledScript: in many ways ''Destroy All Monsters'' is a repeat of ''Film/InvasionOfAstroMonster.'' HumanAliens from the outer solar system with a specific and well-hidden AchillesHeel secretly establish a base in Japan and use their advanced technology to control a group of monsters, which they send to destroy major human cities. The protagonists are astronauts and scientists who use their own technology combined with some quick thinking to exploit the aliens' weakness and break the control over the monsters, allowing the whole thing to be settled in a kaiju brawl. In both cases, the aliens' ultimate weapon whom the other monsters team up against in the climax is King Ghidorah. Much of the structure of both these films would be recycled again decades later in ''Film/GodzillaFinalWars.''
* WhatCouldHaveBeen: The monster selection of the film was intended to be far larger than in the final film. Originally the original plan was to show all of Toho's Kaiju in one film together (including all of the ones who seemingly died in their previous entries, such as Frankenstein (who drowned in ''Film/FrankensteinConquersTheWorld''), the Gargantuas (burnt to death by a combination of napalm and a volcanic eruption in ''Film/WarOfTheGargantuas''), the Giant Condor (killed by Godzilla in ''GodzillaVsTheSeaMonster''), Kamacuras (also killed by Godzilla while they were attempting to eat the egg containing his son in ''Film/SonOfGodzilla'') and even Oodako (who drowned alongside Frankenstein), Kaiju such as [[Film/{{Gorath}} Maguma]] and [[Film/EbirahHorrorOfTheDeep Ebirah]] were to be in the film, and Maguma and Baragon were to act as guardians to the Kilaaks in fending off the SDF. However, due to the frail conditions of the suits owing to constant modifications and use in ''Series/{{Ultraman}}'', Anguirus, Gorosaurus, and Minya were substituted instead. Baragon did appear several times in the movie, but Maguma was cut altogether.