The 600-year-old Voynich Manuscript is so baffling that some people believe it might have been the work of an elaborate ancient prankster. It seems designed to defy translation, despite the fact that whoever made it in Central Europe put a lot of time into its creation.
Page after page of looped text is contained within the manuscript, along with many illustrations. The current theory is that they might be an encoded form of old Hebrew, but even then, we can't make coherent sentences from the text.