The Return of Colossus

Which machine started the computer revolution? Some say the ABC at Iowa State was the first computer, but it never got used in a practical way. Others credit Eniac, which wasn't technically first but got the public and government excited about computing.

It's hard to underestimate the influence of Colossus, however. The British-built programmable system at Bletchley Park, England, helped crack the secret codes of the Third Reich and speed the end of World War II.

The MK 1 Colossus was built in 1943 and used 1,500 vacuum tubes to calculate. By June 1944, subsequent Colossus machines using 2,000 valves were cracking German high-command codes to pave the way for D-Day. It wasn't, however, used to crack Enigma, which we posted on earlier, but later, more complex machines. (With all the WWII memorabilia, you'd think you're on the History Channel web site.)

The British government dismantled it at the end of the war to prevent any Cold War enemy from discovering such advanced technology.

Pictured here is the nearly rebuilt Colossus. A group of enthusiasts has been working on it for nearly a decade. Completion is on track for the summer.