II.

Land and Resources

The peninsula is essentially a vast plateau, bordered on the west and south by mountains that rise steeply from the Red Sea. In the east, the peninsula slopes gently to the Persian Gulf. It contains some of the world's largest sandy desert areas, notably the Rub‘ al Khali ('Empty Quarter') in the south and An Nafūd in the north. The climate is extremely arid; few places receive more than 178 mm (7 in) of rain a year and no permanent streams exist. Hot, dry winds sweep the peninsula, and summer temperatures can reach as high as 54.4° C (130° F). Various minerals, including gold, silver, sulphur, and salt, are produced. The region, however, owes its modern economic life and importance to the vast reserves of oil and natural gas, found mainly in the area around the Persian Gulf. Major cities include Riyadh, Mecca, Medina, Aden, Jiddah, Sana'a, Abu Dhabi, and Kuwait.