30th October 1942: German Enigma machine ciphers retrieved from submarine U-559 by British sailors

A British party of Lieutenant Francis Fasson, Able Seaman Colin Grazier, and canteen assistant Tommy Brown, boarded the slowly-sinking submarine after it had been damaged by depth charges and retrieved the Enigma codebooks and all the current settings for the U-boat network.

8th June 1959: The world’s only delivery of ‘Missile Mail’ took place when the United States Post Office Department sent 3,000 letters using a cruise missile

The missile was fired from the deck of the submarine USS Barbero towards the Naval Auxiliary Air Station in Mayport, Florida, and completed its 700-mile flight in just 22 minutes.

21st January 1954: Launch of USS Nautilus, the world’s first nuclear-powered submarine

Nuclear propulsion enabled Nautilus to smash numerous records including those for both submerged speed and distance, and became the first submarine to transit the North Pole in August 1958.