This is a test I did with a map for Unreal Tournament called "VCTF-Retribution", downloaded from here long time ago:
https://forums.epicgames.com/threads/959143-VCTF-Retribution
I have included it in my main 10x10 km map as an stream level (the map are loaded when you are near).
I wanted to have an idea as how the game can look once finished, using a well finished map like this.
This is only a test, the game is ambiented in the ancient Mesopotamia, and this level doesn't fit. It's only a test.
In this video you can see: