Imagine this for Manaan:
You leave Ahto City to go to a remote platform that only has room for a couple of boats and a space ship's landing pad. Also on this platform is an elevator that takes you to the depths of Manaan, where you can enjoy all of the underwater sea life and beauty that the inhabitants enjoy on a daily basis. The main room can have a giant pane of glass to see the underwater aquatic life! It could be just as big as the Nar Shaddaa one!