The Invasion - S6-E3
Trivia: The episode was intended to prove that Earth-based stories could be produced cheaply and effectively. Ironically, it was the most expensive Doctor Who episode ever produced when made, and remained so for several years.
DaveJB
4th Feb 2005
Doctor Who (1963)
3rd Nov 2004
Doctor Who (1963)
The Daleks' Master Plan - S3-E4
Trivia: Originally the Time Destructor's core was made out of "Vitaranium." It was changed to "Taranium" after William Hartnell kept calling it "Vitamin."