The Middle East extends from Turkey to the Persian Gulf. Saudi Arabia is geographically the largest Middle Eastern nation, while Bahrain is the smallest. Arabs, Turks, Persians, and Kurds constitute the largest ethnic groups in the region by population. Most of the countries that border the Persian Gulf have vast reserves of crude oil, which have significantly contributed to the economy. Tourism continues to rise, with Turkey, the United Arab Emirates (Dubai), Iran, and Jordan being the most visited.