So does anybody know that bridge I'm talking about?
Dozens of z-levels high, big spectacular arched columns...
I have no clue.
ANYWAYS....
I really want to do a megaproject (my first one) with my current fort but I can't decide whether to do an obsidian sphinx, an aztec style green glass pyramid (clear glass is also an option, but wood is pretty scarce even with trade, not to mention the lengthy prep required), or something else.
Here is a view of the area.
I know there is some space to the south (my entrance faces west), but the area I walled off was easier to secure. The big wall is my shield wall to keep gobbos from sniping at my dwarves. I do have magma, but I'm not planning on using it since I have zero experience moving it up z-levels and besides it's three levels below the ground and my fort is pratically on top of it. However, there is a UG river which is up above my fort at 30 z-levels above the flat area (the water is actually at 29 z-levels above, 30 z-levels is the 'surface' of the UG river) and I did have some idea about using the walled in area like a huge tank and doing something water related. In fact, I've already tapped it for my elf drowning chamber and the ability to send water through the entranceway. I have 59 z-levels to work with, iron seems abundant, there is silver and gold available, flux, and I know at least one layer of the mountain has obsidian as a layer stone.
Also, it's not visible, but I have bridges walling off the north and west edges next to the walls and plenty of traps in the entrance. So I'm pretty damn secure here.