Once a day in Dark City, the location of the eponymous science-fiction film (2008), aliens reorganise by force of their minds the physical reality of the urban space. Equally arbitrarily, they rearrange the urbanites’ memories. The cityscape functions, as one character terms it, as an “experiment” to study the essence of being human. The aliens’ method of “research” contrasts with how urban history scholars approach the city. Researchers do not arbitrarily change space but search in the space they find for influences and effects of urban conditions. The built environment and the recurring flows passing through it matter the way they have taken shape in time, representation, experience, and memory. Haphazard reconfigurations of that environment would deny researchers the opportunity to identify coherent meaning in the spaces we live in. Nevertheless, the aliens-cum-researchers’ mental freedom to create alternative urban scenarios is thought-provoking. When exploring city structures, a little bit of alternative thinking might enrich our reflection on our scientific research of the facts. What if a specific urban structure was different? What if this structure did not exist? The probing “if” might broaden our ideas of what difference the existing structures might make, enticing us to search the archives for causes, consequences, and correlations out of the box of what we have hitherto found. We cannot study that which is not, but a small mind game might inspire us to research unconsidered facets of that which is.