The TARDIS is bigger on the inside than the outside, which is commented on by almost everyone who enters. On the inside, the TARDIS looks like a giant spaceship, but on the outside it looks like a police telephone box. These telephone boxes were still a common sight in many British cities when the series first began in 1963, but after the walkie-talkie was invented they were no longer needed. They were used by the police as workstations - and people could also use them to call the police.