UNESCO on Saturday added eight pre-Islamic Iranian archeological sites to its World Heritage List, the UN agency announced at a meeting in the Bahraini capital.
The sites collectively appear on the worldwide list as the "Sassanid Archaeological Landscape of Fars region (Islamic Republic of Iran)".
A province in modern-day Iran's south, Fars was the cradle of the Sassanid dynasty, which appeared at the start of the third century.
After the fall of the Parthian empire, the Sassanids ruled territory that, at its peak, stretched from the west of Afghanistan to Egypt, before falling to the Arab conquest under the Umayyad caliphate in the middle of the seventh century.
"These fortified structures, palaces and city plans date back to the earliest and latest times of the Sassanian Empire," UNESCO said.
With the latest addition, Iran now has 24 sites on the heritage list of the United Nations Educational, Scientific and Cultural Organisation.