This clip from episode one of the Doctor Who story 'The Enemy of the World' shows the Doctor, played by Patrick Troughton, going for a dip in the sea.
The 1967 episode is one of nine tracked down in a store room at a Nigerian TV station, where they were gathering dust.
Footage courtesy of BBC Worldwide.
More top news
Every school rated as inadequate by Ofsted will be turned into academies under new laws, the Education Secretary has announced.
The new Teletubbies have been revealed - complete with touch-screens on their stomachs.
US whistleblower Edward Snowden has said becoming an "international fugitive" has been worth it.