As the first overall formalization of Bernhard Hafner’s research, City in Space represented a nodal element of the spatial city. It was a gigantic network of infrastructures, offering a futuristic and sophisticated picture of the city of transport and communication. This urban nucleus concentrates all the programmes and amenities of social life in a single, vertical bundle. The housing units are set on three-dimensional grids with infinite growth, based on the principles of orientation defined by the Archegrams. Public and cultural places function like multi-purpose spaces with variable forms and are connected along the vertical axis. This latter is traversed perpendicularly by the sheaths of multiple networks, which form the longitudinal thoroughfares of the spatial city and are earmarked for high-speed traffic. By thus likening the urban space to a huge exchanger of flows, Hafner makes an immediate transfer from technology to architecture. The axonometric views, which are eye-catching because of the refinement and complexity of the design, serve the architect’s analytical approach while at the same time helping to project this piece of city into an abstract and floating space, outside any location.