This is an all-in-one, extensible and movable bathroom which compresses the functions of toilet bowl, washing basin, shower, and storage into a closet-sized space. The integrative design and modularity largely reduces the building materials, spaces as well as the time and cost needed for construction. The foldable toilet bowl discharges waste circuitously using a new technology that allows more flexibility and hence reduces the space needed for a toilet. One Bathroom introduces a new approach to toilet design ideally suited to small flats in high-density cities like Tokyo, Hong Kong, Shanghai, and Beijing.