Rongorongo
Rongorongo ( /ˈrɒŋɡoʊˈrɒŋɡoʊ/; Rapa Nui: ) is a system of glyphs discovered in the 19th century on Easter Island that appears to be writing or proto-writing. Numerous attempts at decipherment have been made, none successfully. Although some calendrical and what might prove to be genealogical information has been identified, not even these glyphs can actually be read. If rongorongo does prove to be writing and proves to be an independent invention, it could be one of very few independent inventions of writing in human history.
Read more about Rongorongo.