The Sahara is the world's second largest desert (second to Antarctica), over 9,000,000 km² (3,500,000 mi²), located in northern Africa and is 2.5 million years old. The entire land area of the United States of America would fit inside it. Its name, Sahara, is an English pronuciation of the word for desert in Arabic.
The boundaries of the Sahara are the Atlantic Ocean on the west, the Atlas Mountains and the Mediterranean Sea on the north, the Red Sea and Egypt on the east, and the Sudan and the valley of the River Niger on the south. The Sahara is divided into western Sahara, the central Ahaggar Mountains, the Tibesti massif, the Aïr Mountains (a region of desert mountains and high plateaus), Tenere desert and the Libyan desert (the most arid region). The highest peak in the Sahara is Emi Koussi (3415 m) in the Tibesti Mountains in northern Chad.
The Sahara divides the continent into North and Sub-Saharan Africa. The southern border of the Sahara is marked by a band of semiarid savanna called the Sahel; south of the Sahel lies the lusher Sudan.
Humans have lived on the edge of the desert for almost 500,000 years. During the last ice age, the Sahara was a much wetter place, much like East Africa, than it is today. Over 30,000 petroglyphs of river animals such as crocodiles survive in total with half found in the Tassili n'Ajjer in southeast Algeria. Fossils of dinosaurs have also been found here. The modern Sahara, though, is generally devoid of vegetation, except in the Nile Valley and at a few oases and in some scattered mountains and has been this way since about 3000 BC.
2.5 million people live in the Sahara, most of these in Mauritania, Morocco and Algeria. Dominant groups of people are the Tuareg-Berber, the Sahrawis, Moors, and different black African ethnicities including the Tubu, the Nubians, the Zaghawas and the Kanuri. The largest city is Nouakchott, Mauritania's capital. Other important cities are Tamanrasset, Algeria; Timbuktu, Mali; Agadez, Niger; Ghat, Libya; and Faya, Chad.
By 2500 BC the Sahara was as dry as it is today and it became a largely impenetrable barrier to humans, with only scattered settlements around the oases, but little trade or commerce through the desert. The one major exception was the Nile Valley. This well watered section of the desert became one of the most densely populated regions on the planet and the home to one of humanity's earliest civilizations. The Nile, however, was impassable at several cataracts making trade and contact difficult. Over time Egypt spread south and technologies such as iron working, and perhaps ideas such as that of monarchy spread into Nubia and further south.
Sometime between 633 and 530 BC Hanno the Navigator either established or reinforced Phoenician colonies in the Western Sahara, but all ancient remains have vanished with virtually no trace
By 500 BC a new influence arrived in the form of the Greeks and Phoenicians. Greek traders spread along the eastern coast of the desert, establishing trading colonies along the Red Sea coast. The Carthaginians explored the Atlantic coast of the desert. The turbulence of the waters and the lack of markets never led to an extensive presence further south than modern Morocco. Centralized states thus surrounded the desert on the north and east; it remained outside of the control of these states. Raids from the nomadic Berber people of the desert were a constant concern of those living on the edge of the desert.
The greatest change in the history of the Sahara arrived with the Arab invasion that brought camels to the region. For the first time an efficient trade across the Sahara desert could be conducted. The kingdoms of the Sahel grew rich and powerful exporting gold to North Africa. The emirates along the Mediterranean sent south manufactured goods and horses. From the Sahara itself salt was exported. This process turned the scattered oasis communities into trading centres, and brought them under the control of the empires on the edge of the desert.
This trade persisted for several centuries until the development in Europe of the caravel allowed ships, first from Portugal but soon from all Western Europe, to sail around the desert and gather the resources from the source in Guinea. The Sahara was rapidly remarginalized.
The colonial powers also largely ignored the region, but the modern era has seen a number of mines and communities develop to exploit the desert's natural resources. These include large deposits of oil and gas in Algeria and Libya and large deposits of phosphates in Morocco and Western Sahara.
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Sahara".