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
Gunmen have stormed a restaurant in Dhaka, Bangladesh, taking a number of hostages and opening fire at police. Here's what we know.
Wales came from behind to make history as a 3-1 win propelled them into the last four of a major football tournament for the first time.
Oliver Paps said: "I'm going to jump in the air - take a photo for me as a memory", before plunging 200ft to his death, witnesses said.