21 January (releases)


 * 1967 - Episode two of The Underwater Menace was first broadcast on BBC1.
 * 1967 - Part one of the TV Comic story The Trodos Ambush was first published.
 * 1978 - Part three of Underworld was first broadcast on BBC1.
 * 1978 - Part two of the TV Comic story The Snow Devils was first published.
 * 1988 - The novelisation of The Rescue was first released in paperback by Target Books.
 * 1993 - DWM 196 was first released by Marvel Comics.
 * 2002 - The audio story Project: Infinity was released by Big Finish Productions.
 * 2007 - Immortal Beloved was broadcast on BBC7.
 * 2009 - The Doctor Who: Battles in Time comic story Metal Mania was first published.
 * 2010 - Doctor Who at the BBC: A Legend Reborn was first released by BBC Audio.
 * 2010 - The Doctor Who Adventures comic story The Unwelcome Visitors was first published.
 * 2010 - A Thousand Tiny Wings and Leviathan were first released by Big Finish Productions.
 * 2020 - Dark Universe was first released by Big Finish Productions.
 * 2021 - 24 Carat was first released on the official Doctor Who YouTube channel.