I started this project a few years ago with a friend, now on our private server.

We tried to make a huge building, in which dozen generations of people lived,
so we first built a "frame" (empty tower), then we added houses, corridors, modifying walls.
There are several level, the lower ones are entirely filled with various public buildings, houses, shops, etc...
A large part of the tower collapsed, there is mainly grass and trees there :D
Feel free to take a walk in  the world too, you can use the railway to visit several places of interest

You can find more screenshots of the server HERE.

I used several different resource packs, and SEUS shaderpack to take the screenshots.

My personal resource pack :
Joe's Pack
This is the one I use now for most of the screenshots,
it's still WIP, but fell free to share your thoughts about it :)

the Pixel Perfection Pack, by XSSheep