Cyrus the Great Day (Persian: روز کوروش بزرگ Rūz-e Kuroš-e Bozorg) is an unofficial holiday in Iran.

Secular and nationalist in nature, it commemorates the legacy of Cyrus II of Persia, who founded the Achaemenid Empire in the 6th century BCE.

[2] Based on some historical records, 29 October was the day when Cyrus entered Babylon after the Neo-Babylonian Empire fell to the Achaemenid Persians in the Battle of Opis.

[6] In 2017, Bahram Parsaei, the representative of the electoral district of Shiraz in the Iranian parliament, openly voiced the demand for the state to recognize and observe the holiday.

",[9][10][11] "Iran is our homeland; Cyrus is our father," and "Clerical rule is synonymous with only tyranny, only war", as well as "Freedom of thought cannot take place with beards" were among the slogans in the amateur videos going viral on social media.