[custom_adv] Saudi Arabia, officially the Kingdom of Saudi Arabia (KSA), is a sovereign Arab state in Western Asia constituting the bulk of the Arabian Peninsula. [custom_adv] With a land area of approximately 2,150,000 km2 (830,000 sq mi), Saudi Arabia is geographically the fifth-largest state in Asia and second-largest state in the Arab world after Algeria. [custom_adv] The area of modern-day Saudi Arabia formerly consisted of four distinct regions: Hejaz, Najd and parts of Eastern Arabia (Al-Ahsa) and Southern Arabia ('Asir). The Kingdom of Saudi Arabia was founded in 1932 by Ibn Saud. [custom_adv] Saudi Arabia has since been an absolute monarchy, effectively a hereditary dictatorship governed along Islamic lines. [custom_adv] The ultraconservative Wahhabi religious movement within Sunni Islam has been called "the predominant feature of Saudi culture", with its global spread largely financed by the oil and gas trade. [custom_adv] Saudi Arabia is sometimes called "the Land of the Two Holy Mosques" in reference to Al-Masjid al-Haram (in Mecca) and Al-Masjid an-Nabawi (in Medina), the two holiest places in Islam. [custom_adv] Petroleum was discovered on 3 March 1938 and followed up by several other finds in the Eastern Province. Saudi Arabia has since become the world's largest oil producer and exporter, controlling the world's second largest oil reserves and the sixth largest gas reserves. [custom_adv] The kingdom is categorized as a World Bank high-income economy with a high Human Development Index and is the only Arab country to be part of the G-20 major economies. [custom_adv] However, the economy of Saudi Arabia is the least diversified in the Gulf Cooperation Council, lacking any significant service or production sector (apart from the extraction of resources).