As a possible response to the dawning of a new gründerzeit age, Aspern will see the birth of a new city covering 240 hectares including a lake for 40,000 residents and working people within the next decade. The logical reason for this is that people can reach Bratislava and Vienna within 15 minutes. Such an undertaking requires strong identification points right from the start, and architecture can contribute a lot in that sense. This is where Slim City comes in. 13 slender tower houses of different heights form their own unique quarter on the site – a city in the city, as it were. Open urban space lavishly spread between the buildings is something that is more familiar in anonymous development: a series of different plazas and constrictions – similar, yet varied, public, yet also used privately – which people can just walk through or use in many different ways. Although precisely calculated, these buildings appear to have grown coincidentally. They form units comprising 2 – 3 buildings linked together by bridges, with accesses and addresses located at the relevant bordering street space. The buildings with a total of 174 dwellings obey a canon of formative rules. While standard floors will prevail as long as external conditions remain more or less the same, new circumstances require an immediate response in the form of new ground plans. Recognising one’s own home from the outside helps to take possession of it. By introducing unusual living designs, small offices, commercial street use, a cafeteria-cum-party cellar, a spacious dual-aspect community room with FM services, the ground floor gradually becomes a space for general use, instead of just for living purposes. Open space is determined by its focus on surface water drainage, which is gathered at the lowest point in the centre of the courtyards. Ground level increases diagonally in the quarter by approx. 1.40 m. All points in the terrain are incorporated into the system, creating shallow drainage pits in which puddles can form after heavy showers. Grass and flowers and weeds will then start to grow in every little gap and hollow, making the place look bedraggled and worn right from the start, thereby bringing a touch of the past into the open space. Instead of simulating life with conventional playgrounds, we hope to provide children and youngsters with a real animated environment. Structural constellations, built area, gross floor area and building heights within the site and at border areas are all exactly calculated and comply with land use designation, even if it does not seem so at first sight.