The Ring in Vienna hosts the majority of the public infrastructure of Vienna. It connects the inner city with the former outer ring divided by the Glacis in older days. Part of the ring is the Karlsplatz, where the technical university is placed and the Karlskirche planned by Johann Bernhard Fischer von Erlach stages as an Instagram and leisure hotspot. The former undefined green space in front of these buildings and the added Wien Museum stretches until the Wiener Secession. All mosques redrawn as a part of the research were not only used for prayer and treated as sacred places but functioned as public spaces enriching the city on another level. The Ring and Vienna as a whole are missing a mosque, despite over ten per cent of the population identifying themselves as Muslim. Karlsplatz, a forever unfinished space in the city fabric of Vienna, was chosen to locate the missing public building.