Saudi Arabia is the largest country in Western Asia and one of the largest Arab countries. This absolute monarchy occupies a significant portion of the Arabian Peninsula, spanning the area between the Persian Gulf and the Red Sea. Saudi Arabia is considered the birthplace of Islam as it is home to the two holiest cities, Mecca and Medina. The discovery of large oil reserves in the twentieth century led to rapid economic development in Saudi Arabia. The country attracts over 14 million tourists annually, with a majority of them being religious pilgrims, but there is also an increasing trend of leisure tourism.