Those are the only words that fit. So... I'm a fan of of Patrick McGoohan's The Prisoner, and when Danger Man (released on U. S. TV as Secret Agent) popped up on Amazon's streaming service, I watched an episode, since it's (somewhat -- McGoohan maintained that "John Drake" and "Number Six" were not the same man) backstory for The Prisoner.
Alas, at that time the release started with the second series, which ran two years after the first, and I wanted to get in at the beginning. Last night, I discovered that the first series was now available, and in handy 25-minutes doses.
So I watched the pilot. Set in Italy, a bit of a gimme but not at all bad for a half-hour spy drama. As the credits rolled, I caught the name of the location that had doubled for Italy in the various outdoors scenes: Portmeirion.
Yes, the very same folly-built-large where the entire series of The Prisoner was set; there's only the one. Patrick McGoohan's career as a TV spy began and ended in the very same place.
6 months ago