Iran

Iran is divided into thirty one provinces (ostān), each governed by an appointed governor (استاندار, ostāndār). The provinces are divided into counties (shahrestān), and subdivided into districts (bakhsh) and sub-districts (dehestān).
Iran has one of the highest urban growth rates in the world. From 1950 to 2002, the urban proportion of the population increased from 27% to 60%. The United Nations predicts that by 2030, 80% of the population will be urban. Most internal migrants have settled near the cities of Tehran, Isfahan, Ahvaz, and Qom. The listed populations are from the 2006/07 (1385 AP) census. Tehran, with a population of 7,705,036, is the largest city in Iran and is the capital. Tehran, like many big cities, suffers from severe air pollution. It is the hub of the country's communication and transport network.
Mashhad, with a population of 2,410,800, is the second largest Iranian city and the centre of the Razavi Khorasan Province. Mashhad is one of the holiest Shia cities in the world as it is the site of the Imam Reza shrine. It is the centre of tourism in Iran, and between 15 and 20 million pilgrims go to the Imam Reza's shrine every year.
Another major Iranian city is Isfahan (population 1,583,609), which is the capital of Isfahan Province. The Naqsh-e Jahan Square in Isfahan has been designated by UNESCO as a World Heritage Site. The city contains a wide variety of Islamic architectural sites ranging from the 11th to the 19th century. The growth of the suburban area around the city has turned Isfahan into Iran's second most populous metropolitan area (3,430,353).