The Colossus is a type of computer used by the British during World War II. It was the first programmable computer in the world. The Colossus was used as a codebreaker to decode the Lorenz cipher, giving the Allies valuable military intelligence during the war.
There were two versions of the Colossus computer: the Mark 1 Colossus, which became operational on February 5, 1944, and the Mark 2 Colossus on June 1, 1944. By the end of the war, there were ten total Colossus computers in use.