Bletchley Park is an English country house and estate in Milton Keynes that became the principal centre of Allied code-breaking during the Second World War. The mansion was constructed during the years following 1883 for the financier and politician Sir Herbert Leon in the Victorian Gothic, Tudor, and Dutch Baroque styles, on the site of older buildings of the same name.

During World War II, the estate housed the Government Code and Cypher School , which regularly penetrated the secret communications of the Axis Powers – most importantly the German Enigma and Lorenz ciphers; among its most notable early personnel the GC&CS team of codebreakers included Alan Turing, Gordon Welchman, Hugh Alexander, Bill Tutte, and Stuart Milner-Barry. The nature of the work there was secret until many years after the war.

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