The Middle East is a region that roughly encompasses Western Asia. The history of the Middle East dates back to ancient times, and throughout its history, the Middle East has been a major centre of world affairs. The Middle East generally has an arid and hot climate, with several major rivers providing for irrigation to support agriculture in limited areas, especially in Mesopotamia and the rest of the Fertile Crescent. Many countries located around the Persian Gulf have large quantities of crude oil, which has resulted in much wealth particularly for nations in the Arabian Peninsula. In modern times the Middle East remains a strategically, economically, politically, culturally and religiously sensitive region.