The TARDIS, which stands for "Time And Relative Dimension In Space," is a fictional time machine and spacecraft from the British television series Doctor Who. It is known for its iconic blue police box exterior, which is much larger on the inside, allowing it to travel through time and space. Inside, the TARDIS features advanced technology and a unique control room, often described as a blend of retro and futuristic design. The TARDIS is piloted by the Doctor, a Time Lord who uses it to explore different planets and historical periods, encountering various alien species and challenges along the way.