Despite popular folklore, Narciso Monturiol did not build the very first submarine. (Our "Timeline of Submarine History" illustrates that submarines were being built as early as 1620.) However, Narciso Monturiol did build one of the most advanced submarines available at the time.
Narciso Monturiol was inspired to invent a device to aid the Spainish coral divers who fished off the coast of Cadaques. His submarine was intended to save the divers manual labor and reduce their exposure to diving risks. In 1859, Narciso Monturiol's Ictineo submarine was first launched from Barcelona and proved to be submergable for up to two hours. The Ictineo was manually powered by sixteen men turning the propeller. By 1864, Narciso Monturiol had redesigned the Ictineo adding a steam generator for power. The Ictineo could then reach depths of up to thirty meters, and stay submerged for up to seven hours. As a commercial venture the Ictineo failed finding no customers, Monturiol even offered the Ictineo to the Confederacy to help break the Federal blockade. The Confederacy turned down the offer and eventually, Narciso Monturiol turned his attention to shipwreck recovery.
One interesting fact about the Ictineo submarine is that Jules Verne, the famous writer of 20,000 Leagues Under The Sea based his fictional Nautilus submarine after the Ictineo.