Alan Turing: How To Change History Twice In A Single Moment

This is Alan Turing.

The man who changed history twice in a single day.

The first time I ever heard his name was in a computer science class, where we studied different kinds of basic machines and how they work.

One of them was called a Turing machine. Alan invented it. It’s primarily a theoretical model, but this is what his implementation looked like:

The Bombe.

It looks big and clunky and mysterious, but on the inside, you can imagine it a bit like this:

The idea of a Turing machine.

A Turing machine really only does a few things:

  • It moves a tape back and forward, that has symbols written on it in single cells.
  • It reads one of these symbols at a time.
  • It ties these inputs to certain outputs.
  • It writes the output on the tape, and moves on.
Basic idea of a Turing machine at work.
The Turing machine changed the course of history unlike any other invention ever made.

The moment Alan Turing got his theoretical model to work inside a real-world machine is one of the greatest moments in the history of mankind.

In the summer of 2016, I visited a spies and secret agents exhibition with my Dad. There were a ton of cool things to see, like tranquilizer pens, rigged phones, and agent files.

But when I saw this one, little machine, sitting behind a window, I stopped dead in my tracks. Photos weren’t allowed, sadly, but this is what it looked like:

Looks like a…typewriter?

The machine is called Enigma.

The word is Greek and means ‘mysterious.’ It’s a coding device, which was invented by a German engineer, Arthur Scherbius, at the end of WWI, and refined and improved over time.

In WWII, the Enigma was used to encrypt all German military communication, and was considered uncrackable.

Since it used different rotors, letters and numbers to transform the letters in messages, Enigma could create up to 158,962,555,217,826,360,000 (nearly 159 quintillion) different settings — which the Germans changed every 24 hours.

Captain Ridley’s Shooting Party

After graduating from Cambridge and getting his PhD in mathematics from Princeton, Turing worked part-time for the Government Code and Cypher School, helping to decipher encrypted messages.

On 4 September 1939, the day after the UK declared war on Germany, Alan Turing reported to Bletchley Park, where he and a team of the best British scientists worked on breaking Enigma.

An early gathering of Captain Ridley’s Shooting Party (the cover name of the operation).

After almost two years of endless decoding, modeling, calculating…

The intercept control room in Hut 6.

…moving to a restricted area even within the already super secret government facility…

Hut 8

…and spending thousands of pounds and hours on building his machine…

The moment of truth.

…Alan Turing got his machine to work.

On July 9th, 1941, the turing machine broke the Enigma key.

An Unfair Advantage

From that moment on, the allied forces could decode all German communication, unbeknownst to them.

This is what those decrypts looked like in progress:

Good luck with that.

Until the end of the war, for another four years, the allies had an incredible advantage, which, ultimately, won the war.

Historians estimate that breaking enigma shortened the war by two years, saving over 14 million lives.

But here’s the kicker: After the war ended, the concept of the Turing machine was analyzed, improved, and built upon. As a result of generations of research about Turing machines, we now have a different name for them.

They’re called computers.

Out Of The War, Into Prosperity

I couldn’t write this without Alan’s work. And you could never read it.


One man almost single-handedly took us out of one of the worst periods in historic time and into one of the most prosperous.

Alan Turing was instrumental in ending WWII and inventing the computer.

The moment the gears of his machine clicked into place in the right position for the first time is the origin of both.

That’s what I remembered when I saw that little machine, resting behind the glass in that museum.

And I think it’s one of the best moments of humanity. Do you?

If you liked this story from history, please hit the ❤ to share Alan’s amazing work with others!

PS: A great movie about Alan Turing’s life and work is The Imitation Game. I highly recommend it.

I write more here. This was originally published at