During the 20th century submarines became an invaluable part of modern underwater warfare.
1901: The British Navy ordered its first submarine, Holland 1. 3 years later the French produced a diesel driven submarine. Diesel was the preferred fuel until the nuclear submarine arrived.
1914: WWI broke out & British ships were attacked by German U-boats at Scapa Flow. The British realised the level of damage under water attacks could cause.
1939: WWII broke out & a year later, in a breakthrough in submarine development, the Germans produced the first submarine which could operate submerged for an indefinite period.
1955: The US navy commissioned the first nuclear submarine, bringing about a revolution in submarine technology.
An early British Holland submarine. The British were initially reluctant to build a submarine fleet, considering covert warfare operations unsporting. Courtesy of The Royal Navy Submarine Museum, Gosport.