New York apartment scene in UE4, soon to be released on the UE4 marketplace, and later the Unity Asset Store. All models are very low in poly count, and use primarily 2k materials with a few at 4k.
All pieces are modular, (every window piece, roof piece, any wall, sidewalk tile, metal rail, and staircase), resulting in an almost infinite combination of building types.
The walls of the building (brick, etc.) are a separate material slot to allow for customization of each building (or piece).
Took me about 2 weeks to make, and only 1 day to assemble it in UE4.