The TARDIS (Time and Relative Dimension in Space) is a time machine and spacecraft in the British science fiction television program Doctor Who and its associated spin-offs.
When Doctor Who was being developed in 1963, the production staff discussed what the Doctor’s time machine would look like. To keep the design within budget, it was decided to make it resemble a police box.
A TARDIS is a product of the advanced technology of the Time Lords, an extraterrestrial civilization to which the program’s central character, the Doctor, belongs. A properly maintained and piloted TARDIS can transport its occupants to any point in time and any place in the universe. The interior of a TARDIS is much larger than its exterior, which can blend in with its surroundings using the ship’s “chameleon circuit”.