This is my first post and I'm still pretty new to using CC3+, but I'm struggling with bringing my world to life in it.
The portion that I'm working on is a massive underground city. The city expands downwards and has 9 layers at the moment. Each layer has a unique environment to it. Each individual layer has a large population in a main cavern (usually very large) with smaller neighborhoods in attached caverns and caves.
Currently I only have the basic set (City and Dungeon Designer). I would like to know if there is an add on that might work nicely for my city or some overall tips for making caves look really good (I expect I will get better with more experience as well). If someone has any sample underground maps that might help in my decision of what to use that would be great.

Thanks in advance for any help you can provide.