Dalek Invasion of Earth
One of the early scenes in the Doctor Who 50th anniversary episode took place in Trafalgar Square. The location was also used prominently in the second Dalek story, “The Dalek Invasion of Earth”, in 1964.
Near the end of the story, the Doctor (William Hartnell) says farewell to his granddaughter Susan, the first of his companions to leave the show. The clip this screen-shot comes from was used at the beginning of the 20th Anniversary story, “The Five Doctors” in 1983.
Original B&W photos.