I don't fully understand the categories here - I'm picking challenge/adventure because I usually build fantasy/medieval structures. Please point me to the proper category if I am totally offbase.

OK, I'm into the idea of building a dwarven city so here is a small scale entrance. I am a little iffy on the use of quartz even though it is a stone. It just seems to lacks the dwarfy "carven from the bones of the earth" theme.  This was built in a disappointingly flat creative area and I couldn't go any further down because the ground is only a few blocks deep.Neither could I use lava  :(   I will try another approach using a some kind of mountain biome.