The time machine that the BBC's Doctor Who travels around in is called a Tardis, which is an acronym for "Time and Relative Dimension(s) in Space." A product of Time Lord technology, a properly maintained and piloted TARDIS can transport its occupants to any point in time and space. The interior of a TARDIS is much larger than its exterior, which can blend in with its surroundings through the ship's chameleon circuit. However, the one used by the show's character has a damaged circuit, so it always looks like a police call box.