Giù nel blu. Dalla superficie agli abissi: viaggio sottomarino sfogliabile (Down in the blue. From the surface to the depths: a browsable submarine journey) is an illustrated book on the underwater world. Published by the Italian publisher Nomos, the book is written by Gianumberto Accinelli and illustrated by Giulia Zaffaroni.
The book is leafed through vertically and this action together with a metric scale and the color of the pages, gradually darker, gives the readers the idea of descending into the depths, encountering many animals especially in the first pages, leaving room for emptiness and darkness as you go further down, to the depths of the ocean.
The editor also published a sequel called Su nel blu (Up in the blue) which applies the same idea with a different navigation direction: you’ll go from the ground up to the space.