Codebreakers at Britain's Bletchley Park built Colossus in 1943 — considered the world's first programmable electronic digital computer — to crack German ciphers.

Colossus was created to break the high-level Lorenz cipher used by the German high command, and its existence was kept secret for decades after the war. Because it stayed classified, its designers received little public credit at the time, and other machines were long mistaken for the 'first' computer.