I am working on a FPS game. I want to place the action in a real city from 1810 year. I got maps from museum, and a lot of photos, data, items etc from that time. My quiestion is where do I begin to create such city in Unity. I would like to create a map based on the real 1810 map. How do I do it? I haven't found any tutorial on how to create an existing terrain/location based on a reference in Unity. All tips would be appreciated.