Colossus

Today I visited Bletchley Park, home of the World War 2 code breaking operation, Alan Turing and 10,000 (!) others. It's a fascinating place. It is also home of the National Computing Museum, where we saw Colossus the first ever programmable electonic computer. It is a rebuild, as the 10 originals were all destroyed. It uses 2,500 valves, and here are some of them.