(1) For Elon Musk's AI computer, see
Project Colossus.
(2) A British computer that was designed to break German encryption codes in World War II. Installed at the historic Bletchley Park estate in Buckinghamshire, England, the Colossus Mark I was launched in December 1943, and the faster Mark II in 1944. Although it also used vacuum tubes, Colossus was not a general-purpose computation machine like ENIAC in the U.S. It was designed specifically to break encryption codes, and by the end of the war, there were ten Colossus computers in use. All of this was secret until the 1970s. See
ENIAC.
The Bombe
Although Alan Turing is sometimes credited with the design of the Colossus, he developed the electro-mechanical Bombe machine (see
Enigma).