In its first issue in 2019, “XIA intelligente Architektur” presents our Zeil 111 project on six pages. The residential and commercial building, which was built for the Else Kröner Foundation, has already attracted a lot of attention for its innovative, crystalline window structure. This article now describes in detail the many constructional challenges that had to be overcome in building on the narrow plot. The difficulties were exacerbated by the fact that the Hirsch pharmacy had to remain open throughout the construction period. The fact that everything nevertheless went so smoothly and there were no major delays was only possible thanks to the close cooperation of the many people involved, the municipal building inspectorate and the neighbors. However, the effort was worth it: soon after the opening, use of the arcade more than doubled.