The famous structure built to commemorate the 2500th anniversary of the founding of the Persian Empire is the Persepolis. Established by King Darius I in 518 BC, Persepolis served as a ceremonial capital where grand celebrations and religious festivals took place. Its architectural grandeur featured impressive palaces, vast staircases, and detailed reliefs illustrating the empire's diversity. Persepolis symbolizes the achievements of the Achaemenid Empire and stands as a testament to ancient Persian culture and civilization, although it was ultimately destroyed by Alexander the Great in 330 BC. Today, it is a UNESCO World Heritage site.