Iran

Iran, also known as Persia and officially the Islamic Republic of Iran, is a country in West Asia. It is bordered by Iraq to the west and Turkey to the northwest, Azerbaijan, Armenia, the Caspian Sea and Turkmenistan to the north, Afghanistan to the east, Pakistan to the southeast, the Gulf of Oman and the Persian Gulf to the south. With over 90 million inhabitants in an area of 1.648 million square kilometers (0.64 million square miles), Iran ranks 17th in the world in both geographic size and population. Its capital and largest city is Tehran, with around 16 million people in its metropolitan area; other major urban centres include Mashhad, Isfahan, Karaj, and Shiraz.
Iran is one of the world's oldest civilizations, beginning with the Elamites in the fourth millennium BC. It was first unified by the Medes in the seventh century BC and reached its territorial height in the sixth century BC, when Cyrus the Great founded the Achaemenid Empire, one of the largest empires in antiquity. Alexander the Great conquered the empire in the fourth century BC, and it was subsequently divided into several Hellenistic states. An Iranian rebellion established the Parthian Empire in the third century BC, which was succeeded in the third century AD by the Sasanian Empire. Arab Muslims conquered the region in the seventh century AD, leading to its Islamization. Iran became a major centre of Islamic culture and learning, and its culture, language, and customs spread across the Muslim world. A series of native Iranian Muslim dynasties ruled the country until the Seljuk and the Mongol conquests of the 11th to 14th centuries. In the 16th century, the native Safavids re-established a unified Iranian state with Twelver Shia Islam as the official religion.
Under Nader Shah in the 18th century, Iran was a leading world power, though by the 19th century, it had lost significant territory through a series of conflicts with the Russian Empire. The early 20th century saw the Persian Constitutional Revolution, the establishment of the Pahlavi dynasty, and efforts at modernization. Attempts to nationalise the country's vast fossil fuel supply led to an Anglo-American coup in 1953. After the Iranian Revolution of 1979, the current Islamic republic was founded by Ruhollah Khomeini, who became the country's first supreme leader. Iran is officially governed as an Islamic republic with a presidential system, albeit with ultimate authority vested in a theocratic supreme leader (rahbar), currently Ali Khamenei since Khomeini's death in 1989. The Iranian government is authoritarian and has attracted widespread criticism for its significant constraints and violations of human rights and civil liberties.
Iran is a major regional and middle power, due to its large reserves of fossil fuels—including the second largest natural gas supply and third largest proven oil reserves—strategic location in the Asian continent, and role as the focal point Shia Islam within the Middle East. It is a founding member of the United Nations, the ECO, the OIC, the OPEC, the SCO, and a member of BRICS. Owing to its long history and rich cultural legacy, Iran has 27 UNESCO World Heritage Sites—the 10th highest number in the world—and ranks fifth globally in the number inscriptions of Intangible Cultural Heritage. The people of Iran are multicultural and comprise wide variety of ethnic, linguistic, and religious groups.