Iran also known as Persia officially the Islamic Republic of Iran is a sovereign state in Western Asia. With over 80 million inhabitants Iran is the  world's 18th-most-populous country, Comprising a land area of 1,648,195 km2, it is the second-largest country in the Middle East and the 17th-largest in the world. Iran is bordered to the northwest by Armenia and the Republic of Azerbaijan to the north by the Caspian Sea, to the northeast by Turkmenistan, to the east by Afghanistan and Pakistan, to the south by the Persian Gulf and the Gulf of Oman, and to the west by Turkey and Iraq. The country's central location in Eurasia and Western Asia, and its proximity to the Strait of Hormuz, give it 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 fourth millennium BC. It was first unified by the Iranian Medes in the seventh century BC and reached its greatest extent during the Achaemenid Empire founded by Cyrus the Great in the sixth century BC, stretching from Eastern Europe to the Indus Valley, becoming a larger empire than previously ever existed in the world.The Iranian realm fell to Alexander the Great in the fourth 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 seventh century AD, ultimately leading to the displacement of 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 the coup of 1953 instigated by the United Kingdom and the United States, Iran...