Or emperors, if you want to get technical about it.
Four of the Achaemenid emperors after Cyrus -- Darius, Xerxes, Artaxerxes and Darius II -- are buried not far from Persepolis in the cliffs at Naqsh-e Rostam. Or at least that is who traditionally is believed to be buried here; only the tomb of Darius (on the right in this picture) is actually inscribed with a name.
The tomb of Cyrus had a simple majesty; his successors obviously decided to turn the dial to 11. The teeny-tiny people in the bottom of the picture give you an idea of the awe-inspiring immensity of these tombs.