Serial: B  Episode Nos. 5, 6, 7, 8, 9, 10, and 11.  Title: The Daleks (formerly known as The Mutants)

The TARDIS takes the travellers to a world with a petrified jungle, dead metal animals, and a seemingly dormant metal city.  The Doctor wishes to explore the city, and tricks his companions into going there.  He regrets this, however, when they learn the world is soaked in radiation, and that the city still has inhabitants... radiation-mutated creatures called Daleks...

This is the debut story of the Daleks.

starring William Hartnell as Dr. Who, William Russell as Ian Chesterton, Jacqueline Hill as Barbara Wright, and Carole Ann Ford as Susan Foreman.  Written by Terry Nation, Associate Produced by Mervyn Pinfield, Produced by Verity Lambert, Directed by Christopher Barry and Richard Martin..

Originally transmitted from 21 December 1963 to 1 February 1964 on BBC1.