A day of opening instalments.
Barry Letts formally took over as producer with Part One of Doctor Who and the Silurians today in 1970. The title was a mistake, and we usually condense it to just The Silurians.
In 1976 The Seeds of Doom delivered its first episode.
Anthony Ainley made his debut in the series in 1981, playing not the Master but the person whose body he would steal - the anagrammatical Tremas. This was in Part One of The Keeper of Traken.