Sometimes, the best hiding place is right in plain sight. Find out about steganography, the practice of concealing messages right under others’ noses. See how it links with cryptology, the science of secret communication, and how the two have been used in some of history’s biggest moments.

Learn about invisible inks, the Cardano Grille, the use of microdots in WWI, and the butterfly maps of Lord Baden-Powell. And follow steganography into modern day with a hands-on activity and stories of hidden files and cybercrime.