Looking at the machine, it's hard to believe it confounded some of the world's best technical experts, who spent years at places like the UK's secret codebreaking compound at Bletchley Park coming up with ways to crack it.
The machine's innards created an exponentially eye-popping number of possible solutions to a given cipher. The number of possible solutions would take a whole paragraph to write out fully, but can be expressed as about 3.3 x 10^114.
Enigma enthusiast Ralph Simpson told CNET that if you gave 100,000 operators each their own Enigma machine, and they spent 24 hours a day, seven days a week testing a new setting every second, "it would take twice the age of the universe to break the code" by hand.
Before being cracked, Germany's lethal U-boats the power of Enigma to communicate with each other about attacks on merchant ships, which devastated the UK throughout the war, taking thousands of lives and cutting off vital supplies and troops en route from North America.