The 2,500 year celebration of the Persian Empire consisted of an elaborate set of festivities that took place on 12–16 October 1971 on the occasion of the 2,500th anniversary of the founding of the Iranian monarchy (Persian Empire) by Cyrus the Great. The intent of the celebration was to demonstrate Iran's long history and to showcase its contemporary advancements under Mohammad Reza Pahlavi, the Shah of Iran.
The planning for the event took more than a decade. The Cyrus Cylinder served in the official logo as the symbol for the event. With the decision to hold the main event at the ancient city Persepolis near Shiraz, the local infrastructure had to be improved including the airport at Shiraz and a highway to Persepolis. While the press and supporting staff would be housed in Shiraz, the main festivities were planned for Persepolis that for this occasion would be the site of an elaborate tent city. The area around Persepolis was cleared of snakes and other vermin. Other events were scheduled for Pasargadae, the site of the tomb of Cyrus the Great, and Tehran.
The Tent City (also Golden City) was planned by the Parisian interior-design firm of Maison Jansen on 160 acres (0.65 km2) that took its inspiration from the meeting between Francis I of France and Henry VIII of England at the Field of the Cloth of Gold in 1520. Fifty 'tents' (actually prefabricated luxury apartments with traditional Persian tent-cloth surrounds) were arranged in a star pattern around a central fountain, and vast numbers of trees were planted around them in the desert, recreating something of how the ancient Persepolis would have looked. Each tent had direct telephone and telex connections back to its respective country and the whole celebration was televised to the world by way of a satellite connection from the site. The large Tent of Honor was designed for the reception of the dignitaries. The Banqueting Hall was the largest structure and measured 68 by 24 meters. The tent site was surrounded by gardens of trees and other plants flown in from France and adjacent to the ruins of Persepolis. Catering services were provided by Maxim's de Paris, which closed its restaurant in Paris for almost two weeks in order to provide for the glittering celebrations. Legendary hotelier Max Blouet came out of retirement to supervise the banquet. Lanvin designed the uniforms of the Imperial Household. 250 red Mercedes-Benz limousines were used to chauffeur guests from the airport and back. Dinnerware was created by Limoges and linen by Porthault.
The festivities were opened on 12 October 1971 when the Shah and the Shahbanu paid homage to Cyrus the Great at his mausoleum at Pasargadae. For the next two days, the Shah and his wife greeted arriving guests, often directly at the Shiraz airport. On 14 October, a grand gala dinner took place in the Banqueting Hall in celebration of the birthday of the Shahbanu. Sixty members of royal families and heads of state were assembled at the single large serpentine table in the Banqueting Hall. The official toast was raised with a Dom Perignon Rosé 1959.
Six hundred guests dined over five and a half hours thus making for the longest and most lavish official banquet in modern history as recorded in successive editions of the Guinness Book of World Records. A son et lumière show, the Polytope of Persepolis designed by Iannis Xenakis and accompanied by the specially-commissioned electronic music piece Persepolis concluded the evening. The next day saw a parade of armies of different Iranian empires covering two and half millennia by 1,724 men of the Iranian armed forces, all in period costume. In the evening a less formal "traditional Persian party" was held in the Banqueting Hall as the concluding event at Persepolis.
On the final day, the Shah inaugurated the Shahyad Tower (later renamed the Azadi Tower after the Iranian revolution) in Tehran to commemorate the event. The tower was also home to the Museum of Persian History. In it was displayed the Cyrus Cylinder, which the Shah promoted as "the first human rights charter in history". The cylinder was also the official symbol of the celebrations, and the Shah's first speech at Cyrus' tomb praised the freedom that it had proclaimed, two and a half millennia previously. The festivities were concluded with the Shah paying homage to his father, Reza Shah Pahlavi, at his mausoleum.
The event brought together the rulers of two of the oldest extant monarchies, the Shah and Emperor Haile Selassie I of Ethiopia. By the end of the decade, both monarchies had ceased to exist. Orson Welles said of the event: "This was no party of the year, it was the celebration of 25 centuries!"