The six-storey apartment building attempts to redefine the expression of a multi-unit housing building and its relationship with the existing, densely populated, urban fabric of Athens. At the same time, it is a new bioclimatic approach of organizing the front of the building block to the street and the public space of the city. The small plot with an almost triangular shape is what was left unbuilt in the block, defined by a partially demolished, pre-war three-storey building. If this plot was uneconomical and unprofitable for the typical contractor to develop, it consisted of a particular challenge for the design of a new building of small housing units, which would have to evolve in height in 6 floors above the ground floor, with one flat in each level. The tubular-shaped staircase defines and differentiates the building from the adjacent “polykatoikia” and, like a swivel, signifies the vertical circulation. Moreover, it liberates building mass from the party wall, expressing and transferring to the street the dynamic geometry of the triangular plot.