This film has the reputation of being amongst the worst ever made, which -- having finally managed to view a copy (it is barely ever screened and is not available in other formats) -- I think is overstating the movie's faults and understating much of its appeal.
It was directed by Irwin Allen, later known for disaster movies like "The Poseidon Adventure" and "The Towering Inferno", and people are inclined to describe this early effort as something of a shipwreck disaster. Based on a popular history published in the 1920s by one Hendrick Van Loon (very suitable name for the looney tunes feel of this flick), it portrays a "High Tribunal in Outer Space" presided over by Cedric Hardwicke to decide the fate of man -- whether he should be allowed to live or whether he should be destroyed by a "super H-bomb"! The case for survival is pleaded by "the spirit of Man" played by Ronald Colman in his last screen role; the case for destruction is the province of the Devil, Mr. Scratch, as portrayed by Vincent Price. Now these are two of the most mellifluous voices in film history, and I for one am happy to listen to whatever nonsense they may sprout. Between them they review history from biblical times underlining man's good works and his evil ones.
This is where the film garners its bad rep, as Allen depends on stock footage from better films and presents the viewer with one of the most insane casts in film history. For example we have three of the Marx Brothers in their last film together (and in colour) although they share no scenes: Groucho playing a wise-cracking Peter Minuit cheating the Indians out of Manhattan Island, Harpo as a harp-playing Isaac Newton being bombarded with dozens of apples, and Chico as a monk. Among the other weird casting is Hedy Lamarr as the oldest-ever Maid of Orleans -- a 43-year old Joan of Arc, Peter Lorre as Nero, Agnes Moorehead as Queen Elizabeth, Marie Wilson as a streetwise Marie Antoinette, a 21-year old Dennis Hopper as Napoleon with an aging Josephine played by Marie Windsor, and Virginia Mayo in a dark wig as Cleopatra. If you look quickly, you can also spot old-timers Charles Coburn, Edward Everett Horton, Franklin Pangborn, Reginald Gardner, and Cesar Romero. All of this makes it a camp classic in my book and well worth seeking out, if only for its weirdness and madcap conception.