I think it took something around 8 months to make this (I just worked on this once in a while during this time), only focusing more on the past month or so (otherwise I would not finish this anytime soon hahaha). Everything on the scene, from the modeling to lightning was made by me, as a form of learning more about UE4. I learned A LOT regarding Materials, Blueprints and Lightning inside the engine, as well as how to make materials on Substance Designer (all streets' textures were made there), and other overall workflow improvements. Totally worth the effort! :)
The images didn't have any major photoshop enhancement, just some sharpening and mild tone adjustments; the overall quality is 100% from Unreal Engine.
UE4 - Alexander Nevsky Cathedral, Tallinn - Estonia