I guess this really isn't "Showing Off," because i haven't made it yet. I've thrown together a proof of concept on classic, and plan to begin construction on beta soon, but its going to be an intense build (the city will be about twice as large as fort zion, and will need to be hollowed out of stone).
The idea is simple: An underwater city. The water will be held out using signs.
The entrance is pretty straight forward; four spiraling staircases down to the center chute.
The difficult part is the city itself. It will need to be hollowed from stone underground. It will have a vaulted ceiling and water chute down to the basic city "spawn" center.
Tell me what you guys think.
-Humus