I was inspired by the illustration below and I wanted to make my own version in 3D. I am not entirely sure, but I think this illustration is made by Vgjunk. I find it very interesting how the lights and the colours are done. The streets at the bottom are almost completely red and the roofs at the top are black but there is some purple in it too, which gives it a cool kind of haze.
This render took a very long time. To speed up the rendering process I made the white lights on the buildings very weak in the base render pass. This way the lights in the building do not really light up their surroundings and it doesn’t have to be calculated. I added a Vray Self Illumination pass to the render and made the white lights stronger in post production. I made use of the Zdepth render pass to add some purple to the atmosphere.