In 1963, the BBC began production of the longest-running science-fiction television series ever, 'Doctor Who'. The adventures of the mysterious alien time-traveller known as "the Doctor" is now so part of international culture that the image of his blue box is now iconic; more people would know this image as 'The TARDIS' than ever would identify it as a means of communication for bobbies in the 1950s. The introduction of the concept of 'regeneration', which has so far enabled ten different actors to play the lead role, each in their own way, has been one reason for the show's success. The programme originally ran from 1963 to 1989, for twenty-six seasons. The show was successfully relaunched in 2005 by BBC Wales, and is still going strong.