Puzzles, riddles, and cypher - oh my! Lately we've been having codes and secret messages on the brain as we followed along with the spies and sorcerers of The Witch Who Came In From The Cold - Serial Box's espionage fantasy by Lindsay Smith, Max Gladstone, Cassandra Rose Clarke, and Ian Tregillis. It might have reached its finale - but there are still many mysteries to sort out so we're keeping sharp and reading up on all the crafty ways people have hidden information in plain sight.

1. The Caeser Cipher

Although the Roman's code is a pretty simple one, based on shifting the whole alphabet by a chosen number of letters, it worked pretty good for good old Julius, who used it to encode his letters. Later on, in the 1800s, lovers would send secret messages to each other, posted in the personal pages of a newspaper, with this code. And you thought Tinder was confusing!

2. The Enigma code

This was used by the Germans in WWII, and was an incredible complex code, made by specially designed Enigma Machines, which were complex typewriter-codemaker-things. Alan Turing, the British master cryptanalyst, built machines to break these codes, and those machines paved the way for modern computers.

3. The Zimmermann Telegram

This telegram, sent by the Germans to the Mexicans in 1917, and intercepted by the British, was one of the reasons the USA entered WWI. The message, coded numerically, was a suggestion of alliance by the Germans and the Mexicans. Because the United States actually still allowed Germany to send telegrams (and indeed, it would have been difficult for the Germans to reach Mexico otherwise) the message had to be sent in code, because you can't simply knock on your neighbor's door and say, "hey would you mind asking your roommate if they'd like to form an alliance with me against you."

4. The Babington Plot

Sometimes, a broken code can cause you to lose your head. Literally. Mary, Queen of Scots, was imprisoned by her cousin, Queen Elizabeth. Mary, in coded letters, communicated with supporters about overthrowing her queenly cousin. However, unbeknownst to Mary, Elizabeth had snuck a double agent into the communication network, rendering all her codes useless. The resulting evidence of treason was used to behead Mary.

5. Dorabella

Unlike all these historically significant ciphers, the Dorabella Cipher was written... by a lovesick composer to a girl. The man was interested in Dora, and instead of just saying, "Hey, I like you," he decided to write her a code. Made of squiggles. That people still haven’t' cracked, over a hundred years later. Note: if trying to woo using a code, make sure your intended can break the code.

6. Levasseur's Code

Olivier Levasseur was a famous pirate in the 17th century, who amassed a ton of gold by being a ruthless pirate badass. In fact, he may have been the one who started the whole pirate-wear-eyepatches-trend. When he was caught, and standing on the scaffold, he pulled a necklace off his neck and threw it into the crowd. The necklace had a 17 line message, which is still not decoded, but believed to show the way to great treasure.

7. Operation Forte

Do all these codes inspire you to break some of your own? Why not try our Operation Forte Challenge. Each week we post clues that will help you break codes found on ColdWitch.com, and unlock hidden content from our serial The Witch Who Came In From The Cold.Did we miss any cool codes? Sound off in the comments!