Sixty years ago today, Doctor Who replaced its lead actor and kept the show going.

Patrick Troughton's first story, The Power of the Daleks, started on BBC1 on November 5, 1966, and ran six weeks.
The script didn't call it regeneration yet. The Doctor said he had been "renewed."
Between 1972 and 1978 the BBC wiped all six episodes from its archive.
The sound survived because a viewer named Graham Strong had taped the broadcasts at home.

In 2016 the BBC animated the whole story to that original audio, 50 years after it first aired.