Mountains, Plateaus, Deserts. On the north the region is almost completely ringed by mountain ranges. Lesser chains of hills and mountains extend along the coastal areas of the eastern Mediterranean. The Arabian Peninsula, which makes up more than one quarter of the region's area, is bounded by mountainous heights in the west and south. Most of the region's interior is flat and contains some of the world's most forbidding deserts--among them the Libyan (or Western), the Arabian (or Eastern), and the aptly named Rub' al Khali, or Empty Quarter, of Saudi Arabia.

Fertile River Valleys. The region's two major river systems are the Nile and the Tigris and Euphrates. The Nile, the world's longest river, is the lifeblood of Egypt, most of which is otherwise desert. The Tigris and Euphrates rise in Turkey, flow through Syria, and join in Iraq, there forming the region long known as Mesopotamia (meaning land between rivers). These river valleys contain much of the region's limited fertile land and are the most densely populated areas, and it was here that the first known civilizations arose thousands of years ago.

Climate: A Hot, Dry Land. Hot, dry weather is common to the Middle East for much of the year except in the highest mountains, where snow is frequent. The rainy season in most places lasts from about October to April. In the southern part of the Arabian Peninsula, rain comes mainly between May and September. But there is only light, brief rainfall in most of the region and in some areas it never rains at all. In the deserts, which are baked by the blazing sun, the daytime temperature often rises to more than 125°F (52°C). Yet at night the deserts are cool or even cold.

Life itself in the Middle East has long been dependent upon the amount and location of water. Rain-bearing winds are often unable to penetrate into the interior of the region because they are blocked by the surrounding mountains. The best-watered areas are usually the strips of land lying between the mountains and the sea, but the Middle East generally suffers from a severe shortage of water due to the limited rainfall.

Water and History. Long ago the availability of water determined where people could live in the Middle East and how they would earn their livelihood. The amount of available water limited the farmer's choice of crops. It compelled the nomads, who traveled from place to place seeking grazing land for their herds, to rely on goats, sheep, and camels, since cattle could not easily survive in the harsh, dry environment. The location of sources of water also determined the routes of travel and trade.

From earliest times the power of Middle Eastern empires depended on ready supplies of water. It is no accident that the valleys of the Nile and the Tigris and Euphrates rivers were--and remain--main centers of life in the region. Some of the oldest irrigation systems in the world were developed in the Middle East. Many are still in use, along with newer systems.

Dams and Distilling Seawater. Modern methods of providing regular supplies of water in the region include the Aswan High Dam, which irrigates large areas of Egypt and provides hydroelectric power as well. In Israel a pipeline system has been built to divert water from the Jordan River to the desert areas of the Negev. Turkey in 1990 completed the great Ataturk Dam to harness the waters of the Euphrates River. Saudi Arabia, Kuwait, and other countries of the Arabian Peninsula are converting seawater into drinking water by various distilling processes. The success of programs to raise the standard of living throughout the Middle East will depend to a large extent on the outcome of the various water projects.

Chief Cities. Early Middle Eastern civilization developed great cities, and cities continue to play an important role in the life of the region. The largest city of the Middle East is Cairo, the capital of Egypt. Founded by Arab conquerors in the A.D. 900's, it has a population of about 6 million in the city proper and some 14 million in its metropolitan area. The older Egyptian port city of Alexandria, rebuilt by Alexander the Great in the 300's B.C., was famed for its great library, the largest in the ancient world. Istanbul, the major city of Turkey, lies on one of the world's most historic sites, spanning Europe and Asia. As Constantinople, it was once the capital of the Roman and Byzantine empires.

Baghdad, capital of Iraq, lies on the Euphrates River. Founded in the A.D. 700's, it was the seat of the Abbasid dynasty of Muslim rulers, whose most renowned figure was Harun al-Rashid, famed in the West as the caliph in The Arabian Nights. Damascus, Syria's capital, is one of the world's oldest cities, dating back to at least 732 B.C. It was the site of St. Paul's conversion to Christianity, and from A.D. 66 to 750 served as the capital of the Muslim Ummayyad dynasty.

The importance of Jerusalem, Israel's capital, is far greater than its size, containing as it does, places holy to Jews, Christians, and Muslims. Tehran, capital of Iran, is a relatively new city by Middle Eastern standards, first gaining prominence in the 1500's.