Iran is a sovereign state in Western Asia. It is bordered to the northwest by Armenia, the de facto independent Nagorno-Karabakh Republic, the Republic of Azerbaijan, and the exclave of Nakhchivan; 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. With over 79.92 million inhabitants (as of March 2017), Iran is the world’s 18th-most-populous country. Comprising a land area of 1,648,195 km2 (636,372 sq mi), it is the second-largest country in the Middle East and the 18th-largest in the world. It is the only country with both a Caspian Sea and an Indian Ocean coastline. 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.