Captain Jack: What’s with the police box? Why does it look like that?
Rose: It’s a cloaking device.
The Doctor: It’s called a chameleon circuit. The TARDIS is meant to disguise itself wherever it lands. Like if this was Ancient Rome, it’d be a statue on a plinth or something. But I landed in the 1960s, it disguised itself as a police box and the circuit got stuck.
