The Lost World is a 1925 American silent fantasy monster adventure film adapted from Arthur Conan Doyle’s 1912 novel of the same name. The film was produced and distributed by First National Pictures, a major Hollywood studio at the time, and stars Wallace Beery as Professor Challenger. It was directed by Harry O. Hoyt and featured pioneering stop motion special effects by Willis O’Brien, a forerunner of his work on the original King Kong. Doyle appears in a frontispiece to the film, absent from some extant prints.

In 1998, The Lost World was deemed “culturally, historically or aesthetically significant” by the Library of Congress and selected for preservation in the United States National Film Registry.

Plot
From a lost expedition to a plateau in the borders of Peru, Brazil and Colombia, Paula White brings the journal of her father explorer Maple White to the eccentric Professor Challenger in London. The journal features sketches of dinosaurs which is enough proof for Challenger to publicly announce that dinosaurs still walk the earth. Met with ridicule at an academic meeting at the Zoological Hall, Challenger reluctantly accepts a newspaper’s offer to finance a mission to rescue Maple White. Professor Challenger, Paula White, sportsman Sir John Roxton, news reporter Edward Malone (who is a friend of Roxton and wishes to go on the expedition to impress his fiancée), a skeptical professor Summerlee, an Indian servant Zambo, and Challenger’s butler Austin leave for the plateau.

At their campsite at the base of the plateau, the explorers are shocked when a large rock falls, sent their way by an Apeman perched on top of an overhead ledge. As the crew look up to see their attacker, Challenger spies overhead a Pteranodon (mistakenly calling it a Pterodactylus) killing and eating a pig which proves that the statements in Maple White’s diary are true. Leaving Zambo and Austin at the camp, they cross a chasm onto the plateau by cutting down a tree and using it as a bridge, but it is knocked over by a Brontosaurus, leaving them trapped.

The explorers witness various life-and-death struggles between the prehistoric beasts of the plateau. An Allosaurus attacks a Trachodon, and knocks it into a bog. The Allosaurus then attacks, and is driven off by a Triceratops. Eventually, the Allosaurus makes its way to the campsite and attacks the exploration party. It is finally driven off by Ed who tosses a torch into its mouth. Convinced that the camp is not safe, Ed climbs a tree to look for a new location, but is attacked by the apeman. Roxton succeeds in shooting the apeman, but the creature is merely wounded and escapes before he can finish him off. Meanwhile, an Agathaumas is attacked by the Allosaurus, and gores it to death. Suddenly, a Tyrannosaurus attacks and kills the Agathaumas, along with an unfortunate Pteranodon.

The explorers then make preparations to live on the plateau potentially indefinitely. A catapult is constructed and during a search for Maple White, Roxton finds his remains, confirming his death. It is at this time that Ed confesses his love for Paula and the two are unofficially wed by Summerlee who used to be a minister.

Shortly afterwards, as the paleontologists are observing the Brontosaurus, an Allosaurus attacks it and the Brontosaurus falls off the edge of the plateau, becoming trapped in a mud bank at the base of the plateau. Soon afterwards, a volcano erupts causing a mass stampede among the giant creatures of the lost world. The crew is saved when Paula’s pet monkey Jocko climbs up the plateau carrying a rope. The crew use the rope to pull up a rope ladder constructed by Zambo and Austin and then climb down.

As Ed makes his descent, he is again attacked by the apeman who pulls the rope ladder. The apeman is again shot and finally killed by Roxton. They discover the Brontosaurus that had been pushed off the plateau had landed softly in the mud of the river, trapped but still alive, and Challenger manages to bring it back to London, as he wants to put it on display as proof of his story.

However, while being unloaded from the ship it escapes and causes havoc until it reaches Tower Bridge, where its massive weight causes a collapse, and it swims down the River Thames. Challenger is morose as the creature leaves. Ed discovers that the love he left in London has married in his absence, allowing him and Paula to be together. Roxton morosely but gallantly hides his love for Paula as Paula and Ed leave together, while two passersby note: “That’s Sir John Roxton—sportsman.”

Cast
Sir Arthur Conan Doyle as himself (appears in a frontispiece to the film, missing from some prints)
Bessie Love as Paula White
Lewis Stone as Sir John Roxton
Lloyd Hughes as Edward Malone
Wallace Beery as Professor Challenger
Arthur Hoyt as Professor Summerlee
Alma Bennett as Gladys Hungerford
Virginia Brown Faire as Marquette the half-caste girl (uncredited)
Bull Montana as Apeman/Gomez
Francis Finch-Smiles as Austin
Jules Cowles as Zambo
Margaret McWade as Mrs. Challenger
George Bunny as Colin McArdle
Charles Wellesley as Major Hibbard
Nelson MacDowell as Attorney (uncredited)
Chrispin Martin as Bearer/Cannibal (scenes deleted)
Jocko the monkey as himself
Mary the chimpanzee as herself (uncredited)