So this is Naqsh-e-Rostam, in Fars province (near Shiraz). 5 of the ancient Persian Shahanshahs (emperors) are interred there: Darius I, II and III, Artaxerxes, and Xerxes too (the one from "300"). It's 3 000 years old. The little people at its base give you an idea of the size of the thing.