LONDON — “Doctor Who” is turning 50. So what do you get a time-traveling, galaxy-hopping hero who has everything?

Plenty of new time and space on the airwaves.

The BBC is throwing a broadcasting blowout for the sci-fi show, which began with little fanfare and few expectations on Nov. 23, 1963, but is now one of its biggest hits and major exports.

A 75-minute anniversary episode will be shown simultaneously Saturday in almost 80 countries, and there are 3-D screenings in movie theaters around the world.

The anniversary week features hours of supporting programs, online teasers and mini-episodes, and a “Doctor Who” festival at a London conference center. “An Adventure in Space and Time,” a 90-minute drama about the origins of the show, was broadcast in Britain on Thursday and on BBC America on Friday.

“An Adventure in Space and Time” recounts how a group of inexperienced program-makers “set out to create a bit of teatime telly and instead created magic,” scriptwriter Mark Gatiss said.

“Doctor Who” even has royal approval – Britain’s royal family threw a Buckingham Palace reception this week for its stars and creators.

The hoopla contrasts sharply with the BBC’s initially careless attitude to the show. “Doctor Who” has had as many narrow escapes as its hero, a charismatic Time Lord from the planet Gallifrey travels the universe in the Tardis, a time-and-space machine shaped like a blue British police phone box.