Landmarks No.9

The Evil of the Daleks.
In some ways more significant for what it might have been, than what it was. For its first three years, there is a feeling that Doctor Who and the Daleks are inseparable, and the programme needed the metal monsters if it was to continue. Terry Nation certainly felt his creations could survive without the Doctor, and so he attempted to launch them in a TV show of their own. He looked to America to achieve this. He had already stopped writing Dalek stories for the BBC - allowing his friend David Whitaker to write The Power of the Daleks. Now Whitaker would write the final Dalek story - the one which would see the Doctor finally defeat them and destroy their city on Skaro.
So The Evil of the Daleks was almost significant as the last ever Dalek story. As it was, Nation failed to launch his Dalek series, and the BBC discovered that Doctor Who could survive without the Daleks.
This story, and the subsequent Tomb of the Cybermen, are significant for developing their respective alien races. In both we visit their homeworlds (second home for the Cybermen) and get to meet a "leader" who is physically different from the usual members of the species - the huge, immobile Dalek Emperor and the tall Cyber-Controller.
Evil is also significant for being a companion introduction - Debbie Watling's Victoria Waterfield - and for being one of those, still rare, early examples of stories set in contemporary times. Seeing the Doctor and Jamie in a 1960's coffee bar, you realise only Doctor Who could make the contemporary somehow anachronistic.