The ocean meant many things in the 19th century: a battlefield, a gap between nations, a blue abyss of nothingness. To Narcis Monturiol the world of the underwater was alive and infinite. It was a chance for exploration, a source of knowledge, and a refuge from the chaotic state of Barcelona. These thoughts drove Monturiol to design and build one of the first submarines, the Ictineu, a fish-like machine that literally breathed underwater. Against the backdrop of revolutionary Catalonia, the inventor must balance his scientific ferver, his family, his friendships, and his political views. The Art of Underwater Navigation follows Monturiol through his work and life as he fought to produce an improbable dream.