Barely 5 minutes before the episode began filming, news reached the studio that President Kennedy had just been assassinated, putting the actors and crew into a state of shock.
The creature housed inside the Dalek casing was conceived as being frog-like in appearance.
It was associate producer Mervyn Pinfield rather than Terry Nation who suggested that the Daleks should be powered by static electricity. It was originally regular electricity.
William Hartnell at one point cut himself on one of the metal bands around a Dalek's shoulder section. For all subsequent scenes these bands had sticky tape affixed along their edges as a safety measure.
This episode was watched by 8.9 million viewers on its original transmission.