[[quoteright:269:https://static.tvtropes.org/pmwiki/pub/images/corbis-js889-1_464.jpg]]
[[caption-width-right:269: "My brontosaurus has escaped. Keep off the streets until I recapture it." --Professor Challenger]]

''The Lost World'' is a 1925 silent film directed by Harry O. Hoyt. It is an adaptation of Creator/ArthurConanDoyle's 1912 [[Literature/TheLostWorld1912 book of the same name]].

The movie was produced by Creator/FirstNationalPictures, a large Hollywood studio at the time,[[note]]They eventually merged with Creator/WarnerBros[[/note]] and stars Creator/WallaceBeery as Literature/ProfessorChallenger. This version was directed by Harry O. Hoyt and featured pioneering stop motion special effects by Willis O'Brien (an invaluable warm-up for his work on the original ''Film/KingKong1933'' directed by Merian C. Cooper and Ernest B. Schoedsack). Writer Doyle appears in a frontispiece of the film. In 1998, the film was deemed "culturally, historically or aesthetically significant" by the Library of Congress and selected for preservation in the United States National Film Registry.

Every movie featuring dinosaurs, from the Godzilla movies to ''Film/JurassicPark'' owes a nod to this film, as it was the TropeCodifier for dinosaurs as movie monsters. Even ''Film/KingKong1933'' can be seen as a remake of ''The Lost World'' with a giant ape instead of a ''Brontosaurus''.

Not to be confused with the 1997 movie ''Film/TheLostWorldJurassicPark'', which borrows quite a few plot points of ''The Lost World'' nonetheless.
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!!This film provides examples of:

* AbsenceMakesTheHeartGoYonder
* AdaptedOut: The traitorous "half-breeds" Gomez and Manuel, and the entire backstory about Roxton having killed Gomez's brother. Gomez ''may'' have appeared in the deleted sequence involving the cannibal tribe, however.
* AdaptationNameChange: Gladys' last name is changed from Hungerton to Hunger''ford'', and the man she marries while Malone is away, named William Potts in the novel, has been rechristened Percy Potts here in the movie.
* AdventurerArchaeologist: Professor Challenger is more of an adventurer paleontologist.
* AlwaysABiggerFish: An ''Agathaumas'' kills an ''Allosaurus'' in battle, only to fall victim to the bigger and more powerful ''Tyrannosaurus''.
* AnachronismStew: Various species of prehistoric animals from different periods coexist in the plateau, including the Late Jurassic ''Brontosaurus'' and ''Allosaurus'', the Late Cretaceous ''Trachodon'', ''Triceratops'' and ''Pteranodon'', and a primitive hominid, which evolved in the Pliocene.
* ArtisticLicenseBiology: Real spectacled bears [[MisplacedWildlife live in the Andes Mountains]] and are much larger than the [[RuleOfCute tiny cubs]] identified as full-grown spectacled bears in the movie.
* AscendedExtra: Challenger's butler Austin joins the expedition; in the novel, he's barely seen.
* BeastMan: An Apeman that looks like a hairy human with sharp teeth stalks the expedition on the plateau and causes some trouble.
* BehemothBattle: The film features plenty of stop motion dinosaur fights. An ''Allosaurus'' gets to fight a ''Trachodon'', a [[MamaBear mother]] ''Triceratops'' and an ''Agathaumas'' (which is treated as a separate species from ''Triceratops''). The last one kills the ''Allosaurus'', [[AlwaysABiggerFish only to be killed by an even bigger]] ''Tyrannosaurus rex''.
* BerserkButton: Reporters for Prof. Challenger.
* {{Blackface}}: Zambo, the black expedition member, is played by white actor Jules Cowles in blackface makeup. This was 1925, when blackface wasn't seen as offensive yet by the general public.
* BoisterousBruiser: Challenger.
* BreakTheCutie: Paula is teased with the possibility that her father might still be alive, then falls for Malone, only for her father's bones to be found later and Ed to have a fiance.
* BridgeLogic: The expedition gets to the plateau from another cliff by crossing a cut-down tree, which then gets tossed down by a ''Brontosaurus'', trapping them on the plateau.
* BringItBackAlive: The expedition brings back a ''Brontosaurus'' that survived the volcanic eruption.
* CallToAdventure: Malone, who's looking for a way to prove himself as a real man, boldly accepts Professor Challenger's invitation to journey to the depths of the Amazon.
* CannibalTribe: Appears in a deleted scene.
* CanonForeigner: Maple White was given a daughter, Paula, as a love interest for Roxton (and then Malone who unintentionally steals her from him). While she's a typical passive female for most of the expedition, she plays a crucial role in how they escape the plateau: by calling Jocko the monkey, who carries a rope ladder up for them.
* CringeComedy: When Malone goes into his employer's office looking for a dangerous assignment, he immediately spills a bottle of ink all over a desk covered in papers, tries and fails to clean it up with a handkerchief, which he then wipes his face with, covering himself in ink as well, and on his way out he slips and falls headfirst through a closed door.
* DidNotGetTheGirl: The whole reason Malone went on the expedition was to impress Gladys, who marries Percy Potts while he's away. He does however win the hand of Paula - but since Paula was engaged to Roxton, now it's ''Roxton'' who doesn't get the girl.
* DumbDinos: Zig-zagged. Most of the dinos spend their screentime attacking and killing each other and humans, including the herbivorous ''Brontosaurus'' (though it only attacks humans during its rampage in London, which actually would be a realistic scenario for a large animal in a place it would find unsettling). The ''Allosaurus'', for example, goes on to attack a ''Triceratops'' (and gets injured in the process) immediately after it has killed and eaten a ''Trachodon''. The ''Tyrannosaurus'' also goes on to kill a ''Pteranodon'' after having killed an ''Agathaumas''. However, the dinos are shown to be quite agile and lively, and a moment with a mother ''Triceratops'' and her young averts the trope, as the mother makes sure to hide the baby from the ''Allosaurus'' before confronting the predator.
* EscapedAnimalRampage: May have been TropeMaker as far as monster movies are concerned.
* FrazettaMan: The expedition is stalked by a rather monstrous-looking hominid portrayed by an actor in a furry suit and makeup, and his buddy who's just a normal chimpanzee.
* FunetikAksent: The dialogue cards for the expedition members Austin and Zambo are misspelled to represent their accents.
* GentleGiantSauropod:
** Challenger describes the ''Brontosaurus'' as "perfectly harmless". Subverted later in the movie, as the Bronto is forced to defend itself from an ''Allosaurus'', and after it is taken to London, the sauropod panics and goes on a [[EscapedAnimalRampage rampage]].
** Subverted with the ''Brachiosaurus'' during the eruption scene, where it fights with a ''Tyrannosaurus'' and chases away a ''Stegosaurus''.
* GentlemanAdventurer: Lord John Roxton is this, combined with GreatWhiteHunter. He's a well-mannered gentleman and a famous big game hunter. He's also willing to let Paula go, despite having feelings for her, when she reveals she is in love with Malone.
* IWantMyBelovedToBeHappy: This seems to be reason why Roxton lets Paula go when she professes her love for Malone.
* ImprobableTaxonomySkills: The explorers are able to identify the dinosaurs to the precise genus all while looking at them from a distance, despite them only having seen dino skeletons so they should not know precisely what the real versions would look like—especially considering the millions of years of evolution in the interval, as well as the fact that only a handful of dinos had been discovered back then anyway. ([[ScienceMarchesOn To say nothing of feathers]].)
* IntrepidReporter: Edward Malone joins Challenger's expedition to write a story that will impress his fiancée.
* {{Kaiju}}: [[TropeMaker The very first]]. That ''Brontosaurus'' going on a destructive rampage through London was such a trendsetter. It predates ''Film/KingKong1933'' by 8 years and ''Film/{{Gojira}}'' by 29.
* LivingDinosaurs: Might be the first film example of this trope. Surviving dinosaurs are discovered in the eponymous LostWorld.
* LostWorld: A film adaptation of the TropeNamer book. The eponymous Lost World is a plateau in the South American jungle, inhabited by various prehistoric animals.
* MamaBear: The mother ''Triceratops'' protects her calf from the ''Allosaurus''.
* MisplacedWildlife: The plateau is in South America, but most of its inhabitants are species from North America. Along with an African chimpanzee (though it's probably meant to be some sort of prehistoric ape, played by a chimp).
* PublicDomain: While certain restored versions of the movie are owned by the organizations that oversaw them, the heavily-edited 60-minute version is in the public domain and can be found for free in many places online, including Website/{{Wikipedia}} of all places, usually without color tinting and featuring generic music.
* RoarBeforeBeating: In a silent film, no less! In what might be the UrExample in film, ''Allosaurus'' is stalking a grazing ''Trachodon'', but instead of pouncing on it, it roars at it from behind, as if it was challenging it for a fight.
* SkewedPriorities: Summerlee, who stops during the log crossing to examine and capture a beetle, briefly holding the expedition up.
* StaircaseTumble: As in the novel, the tussling Challenger and Malone tumble down the front steps of the Professor's home.
* StockDinosaurArchetypes: Arguably the TropeMaker given its release in 1925 and the first movie to show them in a good variety, the dinosaurs are mostly stereotyped as territorial and aggressive, as shown with ''Allosaurus'', ''Agathaumas'', and ''Tyrannosaurus''. ''Trachodon'' and ''Triceratops'' is more sympathetically portrayed, though the former only serves to be killed and eaten (oddly also shared with ''Pteranodon'') while the latter is a mother defending her calf. Finally, the ''Brontosaurus'' is seen attacking humans, though this only takes place when the dinosaur is taken to London, meaning that it's likely the sauropod is lashing out due to being in unfamiliar lands and acting out of distress and panic.
* TeamPet: Jocko is a pet capuchin monkey who accompanies the expedition.
* TerrifyingTyrannosaur: The first major film example. While ''Allosaurus'' is the film's main predator and described by Challenger as "the most vicious pest", it is ''Tyrannosaurus'' that establishes itself as the dominant predator by killing an ''Agathaumas'' that gored an ''Allosaurus'' to death.
* TerrorDactyl: The first prehistoric creature shown in the film is a massive ''Pteranodon'' that grabs a peccary with its beak and carries it to its perch to eat.
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