The Grand Line, as well as the greater One Piece world, holds a variety of hidden treasures, yet none are as rare and sought-after as the Poneglyphs. These ancient manuscripts are historical records and instructions created by the ancient inhabitants of Wano Country, and when combined, they provide the location of the One Piece, as well as the true history of the Void Century itself.
Source：https://www.cbr.com/one-piece-every-poneglyph/
