WWII: Enigma machine used by the Nazis to send secret messages found in the Baltic Sea

Divers recovered the device at the bottom of Gelting Bay, on Germany's northern coast, while working to remove abandoned fishing nets that threaten marine life. Designed shortly after WWI by the engineer Arthur Scherbius for commercial usage, the cipher engine was adopted by many national governments and militaries. The portable device is best-known for its use by the Axis powers to encode military commands, for safe transmission by radio, as part of their rapid'blitzkrieg' strategy. Enigma featured a number of wheels, which together formed an electric circuit that repeatedly scrambled an entered character -- and reconfigured after each letter. German military models -- made more complex through the addition of a plugboard, for added scrambling -- and their codebooks were highly sought by the allies.