Iran

Asia, and its proximity to the Strait of Hormuz, make it of great geostrategic importance. Tehran is the country's capital and largest city, as well as its leading economic and cultural center.
Iran is home to one of the world's oldest civilizations, beginning with the formation of the Elamite kingdoms in the 4th millennium BC. It was first unified by the Iranian Medes in the 7th century BC, and reached its greatest extent during the Achaemenid Empire founded by Cyrus the Great in the 6th century BC, stretching from Eastern Europe to the Indus Valley, becoming the largest empire the world had yet seen. The Iranian realm fell to Alexander the Great in the 4th century BC, but reemerged shortly after as the Parthian Empire, followed by the Sasanian Empire, which became a leading world power for the next four centuries.
Arab Muslims conquered the empire in the 7th century AD, largely displacing the indigenous faiths of Zoroastrianism and Manichaeism with Islam. Iran made major contributions to the Islamic Golden Age that followed, producing many influential figures in art and science. After two centuries, a period of various native Muslim dynasties began, which were later conquered by the Turks and the Mongols. The rise of the Safavids in the 15th century led to the reestablishment of a unified Iranian state and national identity, which followed the country's conversion to Shia Islam, marking a turning point in Iranian and Muslim history. By the 18th century, under Nader Shah, Iran briefly possessed what was arguably the most powerful empire at the time. The 19th-century conflicts with the Russian Empire led to significant territorial losses. Popular unrest culminated in the Constitutional Revolution of 1906, which established a constitutional monarchy and the country's first legislature. Following a coup instigated by the United Kingdom and the United States in 1953, Iran gradually became closely aligned with the West, and grew increasingly autocratic. Growing dissent against foreign influence and political repression led to the 1979 Revolution, which followed the establishment of an Islamic republic, a political system which includes elements of a parliamentary democracy vetted and supervised by a theocracy governed by an autocratic "Supreme Leader". During the 1980s, the country was engaged in a war with Iraq, which lasted for almost nine years and resulted in a high number of casualties and financial loss for both sides.
According to international observers, the current Iranian government is oppressive, with human rights abuses commonplace. Since the 2000s, Iran's controversial nuclear program has raised concerns, which is part of the basis of the international sanctions against the country. The Joint Comprehensive Plan of Action, an agreement reached between Iran and the P5+1, was created on July 14, 2015, aimed to loosen the nuclear sanctions in exchange for Iran's restriction in producing enriched uranium.
Iran is a founding member of the UN, ECO, NAM, OIC, and OPEC. It is a major regional and middle power, and its large reserves of fossil fuels – which include the world's largest natural gas supply and the fourth-largest proven oil reserves – exert considerable influence in international energy security and the world economy.
The country's rich cultural legacy is reflected in part by its 21 UNESCO World Heritage Sites, the third-largest number in Asia and 11th-largest in the world. Iran is a multicultural country comprising numerous ethnic and linguistic groups, the largest being Persians (61%), Azeris (16%), Kurds (10%), and Lurs (6%).