Owing to budget constraints, many sets were reused: three episodes were set on a submarine and three in the Arctic. Stock footage was often used. As with other ITC productions, much of the exterior action took place in and around the studio lot – in the case of "The Champions", around Elstree Studios in Borehamwood, England. For at least one episode, "Desert Journey", foreign filming did take place, but with a second unit, and extras standing in for the main cast.