Naqsh-e Rustam (also spelled Rostam) near Persepolis, Iran, is the site of 5th century BC royal tomb of ancient Persian kings (Achaemenid empire) built into a cliff. In the foreground is the Ka'ba-ye Zartosht meaning the "Cube of Zoroaster"; an Achaemenid-era tower is 12.5 m high and its original use is still unclear, eather an earlier royal tomb, or a safety boxe for the paraphernalia of rule, or an eternal flame memorial.