 Producer Stanley Chase (qv) said that while its frightening to  suppose a computer could take over the world, it was indeed  possible. His technical advisor said that a machine like Colossus  actually existed at that time. The model for Colossus was supposedly  the NORAD system that controlled our national defense systems, and  thats why the computer programming center in the film was located  in the Rocky Mountains, which is also the home of NORAD. The  government wouldnt allow a film crew on the NORAD grounds, so the  exteriors were filmed at the Lawrence Hall of Science in Berkely,  California. The missile sites were photographed in the California  desert near Palmdale.