Poneglyphs are ancient stone tablets found in the world of One Piece, a popular manga and anime series. They are inscribed with a unique script that holds important historical information, including the location of the One Piece treasure and the history of the Void Century. These tablets are often scattered across various islands and are key to understanding the world's past. Only a few characters, like Nico Robin, can read the Poneglyphs, making them crucial for uncovering secrets and advancing the story's plot.