Made with Mandelbulb3D.
The whole structure is a single fractal shape, not really symmetric. But while making it I decided to use the lower part as a fake reflection of the upper one.
In post production I just blurred the bottom area, added a green algae patch underwater and some clouds in the sky, to make it less boring
Sorry: DA doesn't allow me to use the correct french word: écluses, with the accent, in the title.