Underground troubles!

[Anarki]

Alright. If you were looking for beautiful, underground terrain, then you have not come to the right place.

I'm creating a map, long story short, you have a base on an alien world, in the middle of these weird mountains.

The first four pictures are of the surface. My main problem isn't here, although I am aware that it's still quite bare, and any suggestions for the surface will be welcomed. With cookies. Yes, cookies.

The last picture, however, is what progress I've made with the underground. Yeah, it's that bad. I have no idea what to do. Anyone got a suggestion on how to make a nice underground?

Keep in mind, that this map must be functional, so obstructional terrain just won't do. I want to give the player an 'underground' feeling - I want them to look at it, and go: "oh, yeah, we're underground, and it's dark and creepy". Furthermore, the underground should be able to make an easy transition to straight Blizzard cliffs (ie. underground base entrance).

Also, any advice on how to make the underground seem dark would be welcome.

 

[Nudl9]

Blizzard cliffs is actually better for underground terrain.

 

[Anarki]

I was complementing using them. However, the current tileset is Cityscape (because I need the straight cliff) - and, well, the dirt cliff isn't exactly what I need.

I'd assume there would be some way to turn that dirt cliff into a different tileset's cliff, but I don't know how.

Help?

 

[Argus]

There's a tutorial about it at wc3c, I think...

 

[Belgarath]

Use big rocks and frequent arches raised up on them, and sight blockers so you don't have to mega spam rocks.

 

[Anarki]

Use big rocks and frequent arches raised up on them, and sight blockers so you don't have to mega spam rocks.

Could you give me a link to an example (like a picture)?