The Rosetta Stone is one of the most famous objects in the world, attracting millions of visitors to the British museum every year, and yet most people don’t really know what it is. Discovered in a pile of rubble in 1799, this slab of stone proved to be the key to unlocking a lost language that baffled scholars for centuries.

Carved in ancient Egypt, the Rosetta Stone carried the same message in different languages—in Greek using Greek letters, and in Egyptian using picture-writing called hieroglyphs. Until its discovery, no one in the world knew how to read the hieroglyphs that covered every temple and text and statue in Egypt. Paperback, 336 pages.