Paper? https://www.monperrus.net/martin/store-data-paper https://www.monperrus.net/martin/store-data-paper I mostly jest. It would require a lot of paper. But

Paper? https://www.monperrus.net/martin/store-data-paper https://www.monperrus.net/martin/store-data-paper I mostly jest. It would require a lot of paper. But it should be stable storage for potentially centuries.