A vast, non-Euclidean network of connected pools, corridors

A vast, non-Euclidean network of connected pools, corridors, and flooded maintenance tunnels all in the same aquamarine tile, but decayed, waterlogged, the overhead lights half-submerged or failing. The water level is inconsistent: ankle-deep in some corridors, chest-deep in adjacent rooms that share the same floor. The geometry does not obey gravity in a consistent direction. Black tides move through the lower passages without a visible source slow, enormous, indifferent. --v 8