if not a city

then,

underwater energy generator by underwater current.

 

(use it to build aligning itself vertically) xD

 

 

or underwater city and use pillars to stand solar panels above the sea.

 

power underwater city.

 

 

xDDDD

 

 

Reminds me of BioShock, the game.

 

 

underwater city is possible, but.....

 

what is its use?

 

 

besides symbolism............