Bletchley Park

I have just returned from a lovely day out at Bletchley Park. It was half-term and the place was absolutely heaving with interested families and groups. 
Bletchley Park was where German messages that had been intercepted in World War 2 were sent to be decrypted. The Germans were using a typewriter machine called Enigma which used a series of rotating wheels to change each letter that was typed into another letter. This was then transmitted, and another Enigma machine used to decrypt it back into the original text. 
The problem for the decoders was that they did not have an Enigma machine and the starting position of the rotating wheels was changed at midnight everyday. 
Everyday the intercepted messages would come to different huts on the Bletchley Park site depending on where they thought that they had come from. There were messages arriving from Germany, Italy, and Japan, each an encoded version of the message in the original language. 
The decoders could make a guess at the message because certain messages from particular sources always contained the same information. For example a lonely outpost would always send a standard ‘Nothing Happening’ message. Using this information they used a machine called ‘the Bombe’ which had lots of rotating dials which worked its way through all the wheel combinations until the original message was visible. This then gave the starting wheel positions for that day so they could decode all the other messages that they had intercepted. 
The displays were excellent, and the information about the Enigma machine, and how the code was cracked was very well explained. The reconstruction of the Huts helped you imagine what it would have been like to work there during the war. 
I thoroughly recommend a visit.