Need Help Building an area for a future city

Requesting Trusted and above players for assistance to:
1. Expand the passages and square them off (not rounded)
2. build large circular areas with high ceilings

In CITY, CAVE DISTRICT

The goal is to build a an area with large Halls with vaulted ceilings, Like the MINES OF MORIA. Especially the wanting to build

1.The massive main HALL in the mines with the huge Pillars with cool designes.
Some of the pillars would be cool if broken and some collapsed onto the ground.

2. the passageway that leads to the Bridge WITH lava flowing under and a around a second large Broken Bridge
with a secret staircase that ran down the side of the bridge to the lava with a hidden passage out of the mines. The other side of the bridge there would be a giant "stone"? Creeper statue (instead of the creature that fights Gandalf in the movie) . also in this area lava waterfalls in several locations coming out of the roof and walls, and flooding the floor having large rocks spires/ small stone islands within the lava lake below.

3. the Tomb and with the well, and with large doors and the beam of light shinning onto the tomb
4.large corridors, bridges and staircases every where
5. large vertical multiple story holes that have either lava or water falls, poring down them
6. one or two circular of spherical rooms half filled with water and Greece/ roman circular temples in the middle of them,
7. wells and pillars with flames coming out the top of them
8. Large halls for future plots or for homes build within the cave walls, and shop areas
9. lake filled with lava and some with water
10. Gollums Cave