It's kind of hard to believe that so much can change. The Gateway area of Minneapolis looks completely different from how it looked in the 1950's and earlier. The view from the Metropolitan Building that my characters got is completely impossible, because the Metropolitan Building was torn down and the building that eventually replaced it is eight stories shorter than what was there. Today my characters would be standing on the air, but I made them stand on stone.
In animation I can re-create the Gateway District. It is something completely in my head, but something that is based on research.
In the Minneapolis Collection room of the Minneapolis Central public library, up on the fourth floor, there are many resources, photographs, lists of addresses, and very friendly staff who want to help you. I looked at city directories to see how crowded together the buildings were and I scanned photographs that I could base my drawings on.