(UK title: Monster of Terror, also known as The House at the End of the World) is a 1965 science fiction horror film directed by Daniel Haller, and starring Boris Karloff, Nick Adams, Freda Jackson and Suzan Farmer.

[4] A loose adaptation of H. P. Lovecraft's story "The Colour Out of Space", its plot follows an American man who, while visiting his English fiancee's familial estate, uncovers a series of bizarre occurrences.

Stephen Reinhart, an American scientist, travels to Arkham, England to visit his fiancée, Susan Witley, whom he met while she was studying abroad in the United States.

Stephen confronts Susan about the goings-on, and the two go to investigate the greenhouse; inside, they discover plants and flowers grown to an abnormally large size.

While Stephen goes to investigate in the basement, Susan confronts her father about the discovery they made in the greenhouse, realizing that he has been experimenting with radioactivity to mutate plant and animal life, resulting in dire consequences, such as Letitia and Helga's disfigurements and illnesses.

[6] In the United States, American International Pictures released the film on 27 October 1965 as the first feature on a double bill with Mario Bava's Planet of the Vampires (1965).

Ground fogs swirl round scarred trees, a black-robed figure flits across the background, twigs crumble into dust at the merest touch.

Here are the familiar ornately furnished rooms, gloomy passages and underground stone chambers housing the unearthly secret of the mansion.

But the leading actors seem a little diminished by their surroundings ... though the indefatigable Boris Karloff is as good as ever, and Terence de Marney is an effectively inscrutable Merwyn.