The resolution to the War in the Pacific in 1945 threw a wholly new anxiety onto the shoulders of the world: the heretofore impossible spectre of actual global annihilation. The atomic bombings of Hiroshima and Nagasaki culminated a trend begun with The Great War. In that first conflict, the "Christian Century" of infinite moral progress was crushed beneath the violence of technological warfare predicted by the likes of H.G. Wells, George Tomkyns Chesney, and the other 19th century writers of doomsday invasion stories. Often they predicted an apocalyptic outcome to the oncoming war, but humanity's execution was blessedly stayed in 1919. Even with advances in tank, aeroplane and explosive technologies, truly obliterating humanity was beyond humanity's power.
After several years of production, design and location shooting, Walt Disney released his first Hollywood produced live-action motion picture in 1954. If the advertising was to be believed, it was in fact the mightiest motion picture of them all. Considering that the film was 20,000 Leagues Under the Sea, this is a credible claim.