There is a movie about post-war Warsaw [1], based on Russian airplane photo shoots. The part of the city that looks almost perfectly flat is the former Jewish ghetto. Nowadays, this area has a completely different arrangement of streets, because in 1945 you could not tell very well a street from a building, so it was re-engineered.

[1] https://www.youtube.com/watch?v=Vx3aGiurRbQ