The study concerns the conversion of office spaces into a dental clinic, on the 3rd floor of the historic Athenian office building, the tower of Athens. The main idea of the intervention was to concentrate all the secondary functions of the clinic in an invisible “box” in the center of the space. While, the main functions, reception and movement areas as well as the doctors’ offices, are located around it. This fact allows the direct relationship of the main areas with the characteristic glass facade of the building. These synthetic choices lead to the optimum exploitation of natural light, as much as to the continuous visual relationship of the user with the view of the city and the Attic landscape.