On 21 March, the following important behind-the-scenes events were known to have occurred:
- 1968 - Model filming for The Wheel in Space took place at BBC Television Centre Puppet Theatre. (TCH 12)
- 1969 - Episode five of The Space Pirates was recorded at BBC Television Centre Studio 6. (TCH 14)
- 2006 - Rewrites for The Satan Pit known as "yellow amendments" covered Danny Bartock talking about a virus that could defeat the Ood. (DWMSE 14)
- 2006 - Recording of The Reaping took place at The Moat Studios.
- 2009 - The bookstore scene with Verity Newman in The End of Time was filmed even before the cast read-through of the serial. This was because actor Jessica Hynes was only available to film on that one day before she had to fly to New York to film something else.
- 2012 - Recording for The Rings of Ikiria took place at The Moat Studios.
- 2018 - Recording for The Eighth Doctor: The Time War 2 took place.
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