Ireland!
The United States was the first country to build a nuclear submarine, and that boat was named the USS Nautilus.
Most likely Germany, they had the U-boats (underwater boats)
Britain normally claims the credit.
The Confederate States most successful submarine was the H L Hunley
Periscope
Pepperland was The Beatles destination in the film 'Yellow Submarine'.
Most submarines were made of steel.
The Confederacy led in the experimentation with submarines. The most successful was the HL Hunley. This submarine sunk a Union warship however the sinking ship damaged the submarine that also sank.
Serbia
The first navigable submarine was made in England in 1620 by Conelius Drebbel.American Colonies, 1776, by David Bushnell; the TURTLE piloted by Sgt. Lee Continental Army.
The submarine U-20 was a Type IIB U-boat used by Germany's Kriegsmarine. The U-20 was responsible for the sinking of the RMS Lusitania.