Spiral Cipher
Explorer Academy header image

The Code: Spiral Cipher

If you really want to create a super-secret code, you need to make it up yourself! In the new book Explorer Academy: The Nebula Secret, 12-year-old Cruz Coronado breaks codes in order to fight dangerous villians and solve mysteries. His mom, Petra Coronado, designed her own cipher based on spirals to communicate with him.


Check out the alphabet she created below. Look carefully! The differences between the spirals are small.

Explorer Academy spiral cipher

Crack this Code!

Now use the spiral key to crack the following codes. Then visit to learn how you can win an autographed copy of Explorer Academy: The Nebula Secret using the secret message!

Explorer Academy spiral cipher

NO PURCHASE NECESSARY TO ENTER OR WIN. A PURCHASE WILL NOT IMPROVE YOUR CHANCES OF WINNING. Contest begins on or about August 10, 2018 at 12:01 a.m. ET and ends on August 17, 2018 at 11:59 p.m. ET. See Official Rules at for complete information, including eligibility restrictions, prize descriptions/restrictions/ARVs and complete details. Void where prohibited. Sponsored by National Geographic Partners, 1145 17th Street NW, Washington, DC, 20036.

Enter the world.

Meet Cruz and his friends.

science that inspired the book

Behind-the-scenes book info