The eastern staircase of the Apadana, where delegations from 23 subject nations march in orderly procession toward the king. No two are identical — different dress, different tribute, different faces. It's a stone catalog of the known world, and the craftsmanship is still sharp after 2,500 years.
© Phillip Maiwald (Nikopol), CC BY-SA 3.0, via Wikimedia Commons