Thesis

In 1918, a rotor-based cipher machine was developed by the Germans and became a heavily guarded secret of World War II. This device, the Enigma, converted German military communications into a seemingly unbreakable code. Through international collaboration and use of captured Enigma machines, code books, and cipher keys, the Allies broke this virtually insurmountable barrier. The information obtained by decrypting Axis communications helped Allied forces triumph in military operations such as the Battle of the Atlantic, the North African campaign, and D-Day. Although breaking this barrier was not the only reason for the Allied success, with use of decrypted messages WWII was shortened and millions of lives from both sides were saved. Breaking this barrier has also highly influenced modern cryptological collaboration and development.

"A three-rotor Enigma machine" 1939

Source: lotsearch.de

"Photo taken by the crew of Sunderland Mk.III W4030 "H" of 10 Sqn RAAF which sank U-243 on 8 July 1944:
Six depth charges explode by the stern and cripple U-243 which is shortly thereafter abandoned by its crew
when further aircraft arrive at the scene."

Source: johnknifton.com