Iran (Persian: ایران [ʔiˈɾɒn] (help·info)), officially the Islamic Republic of Iran and formerly known internationally as Persia until 1935, is a country in Central Eurasia, located on the northeastern shore of the Persian Gulf, northwestern shore of the Gulf of Oman, and the southern shore of the Caspian Sea. Both "Persia" and "Iran" are used interchangeably in cultural context; however, Iran is the name used officially in political context. The name Iran is a cognate of Aryan, and means "Land of the Aryans".
The 18th largest country in the world in terms of area at 1,648,195 km², Iran has a population of over seventy million. It is a country of special geostrategic significance due to its central location in Eurasia. Iran is bordered on the north by Armenia, Azerbaijan and Turkmenistan. As Iran is a littoral state of the Caspian Sea, which is an inland sea and condominium, Kazakhstan and Russia are also Iran's direct neighbors to the north. Iran is bordered on the east by Afghanistan and Pakistan, on the south by the Persian Gulf and the Gulf of Oman, and on the west by Turkey and Iraq. Tehran is the capital, the country's largest city and the political, cultural, commercial, and industrial center of the nation. Iran is a regional power, and holds an important position in international energy security and world economy as a result of its large reserves of petroleum and natural gas.
Iran is home to one of the world's oldest continuous major civilizations, with historical and urban settlements dating back to 7000 BC. The first Iranian dynasty formed during the Elamite kingdom in 2800 BC. The Iranian Medes unified Iran into an empire in 625 BC. They were succeeded by three Iranian Empires, the Achaemenids, Parthians and Sassanids, which governed Iran for more than 1000 years. Iranian post-Islamic dynasties and empires expanded the Persian language and culture throughout the Iranian plateau. Early Iranian dynasties which re-asserted Iranian independence included the Tahirids, Saffarids, Samanids and Buyids. The blossoming of Persian literature, philosophy, medicine, astronomy, mathematics and art became major elements of Muslim civilization and started with the Saffarids and Samanids. Iran was once again reunified as an independent state in 1501 by the Safavid dynasty — who promoted TwelverShi'a Islam as the official religion of their empire, marking one of the most important turning points in the history of Islam."Persia's Constitutional Revolution" established the nation's first parliament in 1906, within a constitutional monarchy. Iran officially became an Islamic republic on 1 April 1979, following the Iranian Revolution.
Iran is a founding member of the UN, NAM, OIC and OPEC. The political system of Iran, based on the 1979 Constitution, comprises several intricately connected governing bodies. The highest state authority is the Supreme Leader. Shia Islam is the official religion and Persian is the official language.[24
The term Iran (ایران) in modern Persian derives from the Proto-Iranian term Aryānā, first attested in Zoroastrianism's Avesta tradition.Ariya- and Airiia- are also attested as an ethnic designator in Achaemenid inscriptions. The term Ērān, from Middle Persian Ērān (written as ʼyrʼn) is found on the inscription that accompanies the investiture relief of Ardashir I at Naqsh-e Rustam. In this inscription, the king's appellation in Middle Persian contains the term ērān (Pahlavi ʼryʼn), while in the Parthian language inscription that accompanies it, the term aryān describes Iran. In Ardashir's time, ērān retained this meaning, denoting the people rather than the state.
Notwithstanding this inscriptional use of ērān to refer to the Iranian peoples, the use of ērān to refer to the geographical empire is also attested in the early Sassanid period. An inscription relating to Shapur I, Ardashir's son and immediate successor, includes regions which were not inhabited primarily by Iranians in Ērān regions, such as Armenia and the Caucasus." In Kartir's inscriptions the high priest includes the same regions in his list of provinces of the antonymic Anērān. Both ērān and aryān come from the Proto-Iranian term Aryānām, (Land) of the (Iranian) Aryas. The word and concept of Airyanem Vaejah is present in the name of the country Iran (Lit. Land of the Aryans) inasmuch as Iran (Ērān) is the modern Persian form of the word Aryānā.
The country has always been known to its own people as Iran; however, to the outside world, the official name of Iran from the 6th century BC until 1935 was Persia or similar foreign language translations (La Perse, Persien, Perzie, etc.). In that year, Reza Shah asked the international community to call the country by the name "Iran". A few years later, some Persian scholars protested to the government that changing the name had separated the country from its past, so in 1949Mohammad Reza Shah announced that both terms could officially be used interchangeably. Now both terms are common, but "Iran" is used mostly in the modern political context and "Persia" in a cultural and historical context. Since the Iranian Revolution of 1979, the official name of the country has been the "Islamic Republic of Iran."
Geography and climate
Iran is the eighteenth largest country in the world, with an area of 1,648,000 km2 (636,000 sq mi). Its area roughly equals that of the United Kingdom, France, Spain, and Germany combined, or slightly less than the US state of