Code-breaking personnel at Bletchley Park, 1943.

UNITED KINGDOM - OCTOBER 23: This shows one of the Hut 3 priority teams at Bletchley Park, Buckinghamshire, in which civilian and service personnel worked together at code-breaking. Bletchley Park was the British forces' intelligence centre during WWII, where cryptographers deciphered top-secret military communiques between Hitler and his armed forces. These communiques were encrypted in the 'enigma' code which the Germans considered unbreakable, but the codebreakers at Bletchley cracked the code with the help of 'Bombe' machines. (Photo by SSPL/Getty Images)