The robots Gog and Magog were operated by midgets.
The centrifuge scene was filmed at USC. The actors became sick and were replaced by dummies.
As of April 2005, only one complete dual-projector stereoscopic 3-D print is known to exist anywhere in the world. The Left and Right prints do not match: the color is severely faded on one side, but the film is still viewable in 3-D.
Director Herbert L. Strock had very poor vision in one eye and consequently was unable to properly gauge how the 3-D effects were, and had to rely on others to tell him. Coincidentially, André De Toth, who directed House of Wax (1953), arguably the most famous 3-D film, only had one eye and could not see the 3-D effects at all.
The Hoover Dam's turbines were photographed on glass to provide projected backgrounds to some of the lab scenes.
Herbert L. Strock got in trouble with the Director's Guild for combining his directing and editing credits.
William Schallert was paid $250 for two days' work.
The unusual helicopter seen early in the movie is a McCulloch MC-4C tandem-rotor. Only a handful were built as military prototypes.
The shooting schedule was fifteen days on two sets at Hal Roach Studios, with exteriors at George AFB (Victorville).
Pepe, the subject of the experiment at the opening, is a New World monkey, a capucin, genus Cebus. New World monkeys have prehensile tails and Pepe wraps his tail around his caretaker's forearm.
Shot in 3D, but released mainly in regular 2D.
This rather talky item is from a story by Ivan Tors, producer of TV's Science Fiction Theater, pretty talky in itself. For all that, English was not his native tongue.
The 2016 Kino-Lorber 3D Blu-ray release of this movie features an audio commentary by Tom Weaver, Bob Furmanek and David Schecter.
The base emitted signals to confuse copter nav And base is underground
Base is underground, maze style interior & emits signals that jam copters navigation so pilot cant find base despite repeated trips, see base interior plan on wall.
Film is remarkably prescient in forecasting a technological future. The computer NOVAC has malware on it from a foreign government, the high flying aircraft has stealth capability--not made of metal, and solar energy is perfected to generate electric power.