(cross-posted at Photon Courier)
During WWII, the British used electomechanical devices called bombes to break the German Enigma code. The bombe in its earliest form was developed by the Poles, but was considerably enhanced by the British. (The name probably came from an ice cream dessert popular among the Polish mathematicians who did the original work)
Following WWII, strict secrecy was maintained concerning the codebreaking activities, and all of the bombes were eventually destroyed. Now, a group of volunteers has reconstructed a working bombe–it may be seen at Bletchley Park, which was Britain’s main codebreaking center during the war.