The 2,500th Anniversary of the Charter of Cyrus the Great (also known as the 2,500-year celebration of the Persian Empire) was a series of lavish,, international, and highly controversial festivities held in Iran in October 1971. 

Organized by Shah Mohammad Reza Pahlavi, the celebration marked 2,500 years of continuous monarchy in Persia (Iran), starting from the foundation of the Achaemenid Empire by Cyrus the Great in 550 BC.