158,962,555,217,826,360,000 combinations!
I've always been fascinated by the Enigma machine. Here are two very good videos describing how it worked and its biggest flaw.
Cracking this code must have saved countless lives!
And an entertaining but somewhat inaccurate movie about breaking the code.
https://slate.com/culture/2014/12/the-imitation-game-fact-vs-fiction-how-true-the-new-movie-is-to-alan-turings-real-life-story.html