Once upon a time, a mysterious substance emerged that was so precious, so wondrous to have inspired a kind of worship. That magical object was … a chalk. But not just any chalk! This was Hagoromo: a Japanese brand so smooth, so perfect that some mathematicians wondered if it was made from the tears of angels. But one day it was threatened with extinction, triggering the greatest crisis the world of chalk had ever seen. Pencils down, please, as we tell the tale of a writing implement so irreplaceable, professors stockpiled it. And we’ll meet the brave teacher who singlehandedly saved its legacy from being erased. To learn more about how CNN protects listener privacy, visit cnn.com/privacy Learn more about your ad choices. Visit podcastchoices.com/adchoices