Saudi Arabia is known for its desert climate and enormous oil reserves; it is the largest country in the world not to contain any rivers. The nation is also the birthplace of Islam, and all Muslims who can afford it are obligated to go on a pilgrimage (the "hajj") to the holy city of Mecca at least once in their lives. Saudi Arabia was one of the poorest countries on Earth, with few natural resources and hostile, dry terrain. This all changed with the discovery of the world's largest reserves of oil in 1938.
See also: Hejaz