The TARDIS comes from the TV show Doctor Who. It stands for Time And Relative Dimensions In Space. The TARDIS is a time traveling machine that is bigger on the inside. On the outside it's a blue police telephone booth. On the inside it has a huge room with hallways that lead to nothing, a swimming pool in the library, the heart of the TARDIS, etc. On top of the box it says Police Public Call Box. There is also a panel with a piece of paper that reads, Police telephone. Free for use of public. Advance & assistance obtainable immediately. Officers & cars respond to all calls. It's purpose is to save planets which need help. This happens when a message is sent to the psychic paper so The Doctor can help.