Where can I find great resources for the creation of a subterranean world?
I am looking to create a map of a world underground, kind of like the Underdark. I will have a city made of crystal there along with other features like caverns and tunnels. I am looking for resources to help me achieve this.
Can anybody recommend any annuals or packs that might have good resources for this? I currently own CC3+, DD3, and CD3, but I am very new to all this and feeling a bit overwhelmed with all the information and everything that is available. I would greatly appreciate your assistance!