The set used for the bad guys' headquarters was recycled from the 1966 M-G-M Doris Day vehicle The Glass Bottom Boat (1966). In the Day film, the set appeared as NASA scientist Rod Taylor's home.
The Kit Kat Klub seen here was also seen in Mission Impossible.
Norman Felton, the executive producer, wrote Nelson Riddle a nasty letter about the music because it sounded like his music for the Batman TV series. (Perhaps Riddle was using his music to confirm the feeling that the third season of the show had become "camp" to follow the Batman style.)