The Doctor Who Production Diary: May 21st

1963 It is decided that a pilot episode of Doctor Who will be recorded on July 19th, which can be remounted on August 2nd if necessary The First Doctor
1965 Maureen O'Brien's contract is extended for twelve episodes starting with The Time Meddler Vicki
1965 Peter Purves is contracted to play the companion, now called Steven Taylor, for thirteen episodes starting with episode six of The Chase Steven 
Taylor
1965 Recording for The Chase takes place at Riverside Studio 1 in Hammersmith, London The Chase
1966 The debut broadcast of The Gunfighters episode four, The O.K. Corral, on BBC One achieves Doctor Who's lowest-ever Appreciation index: 30% The Gunfighters
1969 Jon Pertwee is contracted to play the Third Doctor for at least twenty-one episodes The Third Doctor
1970 Recording for Inferno takes place at BBC Television Centre Studio 6 in White City, London Inferno
1974 Birth of Juliet Cowan (bio), who played Chrissie Jackson
1974 A labour dispute cancels recording for Robot at BBC Television Centre Studio 3 in White City, London Robot
1979 Recording for City Of Death takes place at BBC Television Centre Studio 3 in White City, London City Of Death
1980 Recording for State Of Decay takes place at the BBC Visual Effects Workshop in Acton, London State Of Decay
1981 Recording for The Visitation takes place at BBC Television Centre Studio 3 in White City, London The Visitation
1987 Recording for Paradise Towers takes place in Chalfont St Giles, Buckinghamshire Paradise Towers
1996 The FOX network announces its Fall 1996 schedule; Doctor Who is not included, with poor ratings prompting the network to drop the programme The Eighth Doctor
2004 Billie Piper is cast as new companion Rose Tyler Rose Tyler
2005 Debut broadcast of The Empty Child on BBC One The Empty Child / The Doctor Dances
2009 Recording for The End Of Time takes place at HTV Wales Studios in Cardiff, Wales The End Of Time
2011 Debut broadcast of The Rebel Flesh on BBC One and BBC One HD The Rebel Flesh / The Almost People
2014 Recording for Kill The Moon takes place in Wales, at Port Talbot and Roath Lock Studios in Cardiff Kill The Moon
2015 Recording for The Zygon Invasion / The Zygon Inversion takes place at Roath Lock Studios in Cardiff, Wales The Zygon Invasion / The Zygon Inversion
2019 Recording for Fugitive Of The Judoon begins in Cardiff, Wales, and will subsequently involve work at locations including Gloucester, Gloucestershire; Newport, Wales; and the city of Bristol Fugitive Of The Judoon