24 February 1968: broadcast of fourth episode of The Web of Fear. Lethbridge-Stewart (*sigh*) leads a sortie to the surface but returns battered to the base as the only survivor; and the Yeti break in, with the possessed Travers.
24 February 1973: broadcast of first episode of Frontier in Space. The Doctor and Jo land on a space freighter and are accused of being Draconian spies; the freighter is attacked by Ogrons but the crew think they are Draconians.
24 February 1979: broadcast of sixth part of The Armageddon Factor, ending Season 15; last regular appearance of Mary Tamm as Romana. Princess Astra herself is the last segment of the Key to Time; the Doctor assembles it, and the Black Guardian attempts to trick him into giving it to him. But the Doctor disperses the segments across the universe again.
24 February 1984: broadcast of second part of Planet of Fire. On Sarn, the Doctor is captured by Timanov and Peri by the Master (but she escapes).
24 February 1993: broadcast of sixth part of The Ghosts of N-Space on BBC radio; final appearance of Jon Pertwee as the Third Doctor. The Doctor and Sarah enter N-Space where Sarah redeems Louisa and the Doctor defeats Vilmio, and the Brigadier's uncle's castle is saved.