12 March 1966: broadcast of "The Plague", second episode of the story we now call The Ark. The Doctor, Steven and Dodo are on trial; but the Doctor is able to find a cure for the plague, and all watch as the Earth is destroyed.
12 March 1977: broadcast of third episode of The Talons of Weng-Chiang. Leela watches as Weng Chiang kidnaps a girl and drains her of her vital essence, and flees to the sewers.
12 March 1999: broadcast of The Curse of Fatal Death, Steven Moffat's first Doctor Who script, starring Jonathan Price as the Master, Julia Sawalha as Emma, and Rowan Atkinson (and also Richard E. Grant, Jim Broadbent, Hugh Grant and Joanna Lumley) as the Doctor.
12 March 2008: broadcast of From Out Of The Rain (Torchwood), the one with the creepy cinema/