4) Voynich Manuscript
Written in the 1400s this beautiful book is filled with meticulous script, exquisite illustrations, and holds a mystery no one has been able to break in the past 600 years: what is the darn thing about? Like other books of the era, the Voynich Manuscript seems to show formulas, medicinal plants, and illustrations about personal and medical care. Astronomy seems to be another subject of the book, but we really don’t know since the language is unreadable and the plants in the illustrations are unlike anything on Earth.
Some people have been studying the manuscript for decades with no success. The book is part of the rare book collection at Yale University and has even been printed in a modern copy for the perusal of the general public. The book is named for the bookseller who brought it out of hiding after 3 centuries kept hidden away in a monastery. Will this book’s code ever be broken? Why was it created? We may never find out.