police-telephone-box

It’s camouflaged. It’s disguised as a police telephone box from 1963. Every time the TARDIS materializes in a new location, within the first nanosecond of landing, it analyses its surroundings, calculates a twelve-dimensional data map of everything within a thousand-mile radius and then determines which outer shell would best blend in with the environment…. and then it disguises itself as a police telephone box from 1963.
—  Eleventh Doctor