Location filming for "Billion Dollar Brain" took place in Helsinki and other parts of Finland, including Turku. The Riga scenes were filmed in Porvoo, also in Finland. Scenes involving "The Brain" were filmed in Honeywell facilities and featured a Honeywell 200 mini-computer. The remainder of the film was shot in the United Kingdom. Scenes on the ice were filmed on a disused airfield which was covered with a layer of salt. All other scenes were shot at Pinewood Studios, including the scene where Midwinter's convoy falls through the broken ice - this was done in a giant tank with slabs of polystyrene used to represent the ice itself. The large size of the tank was deemed necessary because of the decision to use real vehicles instead of miniatures.