Iran, officially the Islamic Republic of Iran, is a country in Western Asia. It is the second-largest country in the Middle East, and the seventeenth largest in area in the world. Iran is the site of one of the world’s oldest civilizations, which began with the Elamite kingdoms in the fourth millennium BCE. Its long history includes falling to Alexander the Great in the fourth century BCE; the Islamization of Iran, which lead to great contributions to art, philosophy, and science during the Islamic Golden Age; its status as a powerful state in the eighteenth century, and its territorial losses in the nineteenth century due to conflicts with the Russian Empire. Iran boasts a rich cultural history, with 22 UNESCO World Heritage sites.