Tehran

Tehran is the capital and largest city of Iran. It is also the capital of Tehran province and the administrative center for Tehran County and its Central District.

With a population of around 9 million in the city, and 16.8 million in the metropolitan area, Tehran is the most populous city in Iran and West Asia, the largest metropolitan area in the Middle East and the 24th-most-populous metropolitan area in the world. Greater Tehran includes several municipalities, including Eslamshahr, Shahriar, Qods, Malard, Golestan, Varamin, Pakdasht, Qarchak, Nasimshahr, Parand, Pardis, Andisheh, Fardis, Tajrish, and Rey.

Rey is absorbed into the metropolitan area of Greater Tehran. Tehran was first chosen as the capital of Iran in 1786 by Agha Mohammad Khan of the Qajar dynasty, because of its proximity to Iran's territories in the Caucasus—which were contested in the Russo-Iranian Wars—and to avoid the vying factions of prior ruling Iranian dynasties; the capital of Iran had been moved several times throughout its long history, with Tehran becoming the 51st.