Tehran

Tehran is both the country's capital and the administrative centre of the province of Tehran. Tehran is the most populous city in Iran and Western Asia, and it has the second-largest metropolitan area in the Middle East after Cairo, with a population of around 8.7 million in the city and 15 million in the greater metropolitan region of Greater Tehran. By metropolitan area population, it is rated 24th in the world. Aside from that, it is well-known for its vast development and futuristic architecture, which is exemplified by Zaha Hadid's Milad Tower and the Fereshteh Pasargad Hotel, both of which are located in the city.

Rhages, a great Median city that was devastated during the mediaeval Arab, Turkic, and Mongol invasions, inhabited a portion of the land that is now Tehran during the Classical period. Currently, the city of Ray is an urban region that has been integrated into the greater Tehran metropolitan area.

Agha Mohammad Khan of the Qajar dynasty chose Tehran as the capital of Iran in 1786 because of its proximity to Iran's territories in the Caucasus, which were later separated from Iran during the Russo-Iranian Wars, and to avoid conflict between competing factions of the previously ruling Iranian dynastises. Tehran has been the capital of Iran since that time. Tehran is the 32nd national capital of Persia, having been relocated multiple times during the course of its history. Tehran has been a destination for major migrations from all around Iran since the beginning of the twentieth century, when large-scale destruction and reconstruction started.

A number of historical sites, including the royal complexes of Golestan, Sa'dabad, and Niavaran (where the final two dynasties of the old Imperial State of Iran were seated), can be found in Tehran. The Azadi Tower, a memorial built during the reign of Mohammad Reza Shah of the Pahlavi dynasty in 1971 to commemorate the 2,500th anniversary of the founding of the Imperial State of Iran, as well as the Milad Tower, the world's sixth-tallest self-supporting tower, originally planned by the Shah and completed in 2007, and the Tabiat Bridge, which was completed in 2014, are among Tehran's most notable landmarks.

However, huge numbers of various ethno-linguistic groups reside in Tehran and speak Persian as a second language, despite the fact that the vast majority of the population is Persian and around 99 percent of them understand and speak Persian.

Iranian capital Tehran is served by an international airport (Imam Khomeini International Airport) and two domestic airports (Mehrabad International Airport and Tehran Central Railway Station), a rapid transit system (the Tehran Metro), a bus rapid transit system, trolleybuses, and an extensive network of highways.

To address pollution and seismic risks, plans to transfer Iran's capital from Tehran have not yet been approved by the Islamic Republic. The city of Tehran came in at number 203 in a 2016 assessment of 230 cities conducted by the consultancy firm Mercer. Global Destinations Cities Index 2016 indicates that Tehran is one of the ten fastest rising destinations in the world.

Tehran Day was formally established by the municipal council on October 6, 2016, to commemorate the day in 1907 when the city was officially designated as Iran's capital by the Islamic Revolutionary Court.