This is a famous Encryption machine that was created by the Nazi's to send secret messages to each other across battle fields about the status and their placement in WWII. This machine was difficult for the Allies to crack and because they could not figure out what messages the Nazi's were sending their troops were dying and it seemed that the Nazi's were gaining ground. 

Let's look at this lesson on Brilliant.com to learn more about the Enigma machine and how it worked. Enigma Machine