A few meters from Kato Petralona station, the most vivid part of that old Athenian neighborhood, a south-orientated semibasement is transformed into a hybrid social space, hosting both the accommodation of its owner and a live music session bar. The existing building shell is generally left untouched; open-plan, with an underground industrial look, uncoated concrete surfaces, metal details and visible pipes, serving merely as an empty vessel that encloses a collection of designed objects. Those objects may vary from elevated iron-frame wooden platforms that define the different functional entities of the space (kitchen, bathroom, entrance, sleep area, music stage), to glass-brick separators, ventilation systems, or furniture such as a movable ladder, metal storage cabinets, full-height curtains, a table or a stove. All these elements are carefully distributed within the semibasement’s area, some of them fixed in place and others moving, creating a space that can constantly be transformed and adjusted to its users’ various needs. The overall design aims to create a Prohibition Era ambience, inspired by the space’s latent function as a music bar and enhancing its existing qualities, like its brutal materiality and its underground location with the sunlight coming solely from the front ceiling-height windows.