Rosetta stone found in 1799 during the Napoleon's campaign in Egypt is the keystone to decipher Ancient Egyptian scripts. It was dated 196 B.C. and three kinds of glyphs, Greek, Demotic and Hieroglyphic, of a single passage were curved on the stone. Comparative translation of them assisted in understanding the writing system and structure of the Egyptian scripts. Now Rosetta stone is used as idiomatic words for a process of decryption or translation of a difficult problem.
Now we have another Rosetta stone, named Rosetta Project, to archive all the human languages spoken on the earth and build a publicly accessible digital library of human languages. Now it serves nearly 100,000 pages of material documenting over 2,500 languages. Its main concern is the drastic and accelerated loss of the world's languages. It is just one of our LOP's main concern.
You can refer and search resources of this project from the URI below.