A short distance south of Cairo the Nile valley begins to open out into the delta. East of the city, the 700-foot scarp of the Moqattam Hills, at the north end of the limestone plateau, drops off abruptly to the sandy plain that borders the delta on the east all the way to the coastal lagoons. West of the river the gravel hills recede until, just north of Cairo, the valley is in a broad plain over fifteen miles wide. The river, here at its widest and broken by several large islands, keeps to the east side of the valley floor. The cultivated land is west of the river and reaches a width of eight miles opposite Cairo.
Since ancient times this junction of valley and delta has played a commanding role in the various conquests of the country and in its administration, industry, commerce, and communications. Across the river southwest of Cairo are the Great Pyramids and the ruins of Memphis, the capital from which the Pharaoh Menes united the kingdoms of Upper and Lower Egypt. There is evidence that the apex of the delta was then farther south than at present and that Memphis was built on a pronounced westerly bend of the river.
Memphis continued to hold its preëminence in commerce and trade even during the period when the Pharaohs had their seat at Thebes. During the periods of Ptolemaic rule and Roman occupation, although Alexandria became the administrative capital of the country and ultimately surpassed it in size, Memphis was still the largest native city. Only after the conquest by the Arabs and their choice of a more strategic site protected by the Moqattam Hills on the east bank of the Nile was Memphis abandoned, although, because of the shifting of the channel, it had long since lost its riverside location.
East of the Nile, in what is known as Old Cairo, still stand the towers and wall of a fortress built by the Romans on the site of a Persian town called Babylon by the Greeks. Nearby are the sites of a succession of capitals built by the Arabs before the establishment of Cairo itself: Fustat, founded in 640 A. D. by 'Amr, the Arab conqueror of Egypt, and now marked by the latest of a succession of mosques built on the site of a mosque he built; a mound that is all that remains of the town of 'Askar, built as his seat by a Caliph of the succeeding Abbassid Dynasty in 751 A. D.; and the mosque, now restored and one of the sights of Old Cairo, that Ahmad ibn-Tulud, founder of the Tulunid dynasty, built when he moved his seat to Qatai', a suburb of 'Askar. But long before the Persian conquerors built their town of Babylon, there were settlements on this east side of the Nile. The village of Mataria, just north of the residential suburb of Heliopolis, six miles northeast of Cairo, is on the site of a town called On by the early Egyptians and Heliopolis (City of the Sun) by the Greeks, where the Pharaohs worshipped their sun god in his most sacred temple. This side of the Nile was also at various times an entrepôt for the cargoes brought into the valley towns by canal from the Gulf of Suez. It would appear likely that when the first of these canals, the so-called "Canal of the Pharaohs," probably dug during the twelfth Dynasty ( 2000-1782 B.C.), connected the ancient Pelusiac Branch of the Nile with the Gulf of Suez, there were piers and a port settlement nearby, as there must have been when one or another of the conquerors of Egypt restored this canal or dug a new one. Khaleeg Street, which now traverses Cairo for five miles from south (Old Cairo) to north (Daher district) and marks the frontier between the old city and the new, occupies the filled-in course of the old Khaleeg Canal, which connected the Arab conqueror 'Amr's restoration of the "Canal of the Pharaohs" with the main stream of the Nile.
The founding of El Qahira ( Cairo is a corruption of the Arabic name meaning "The Victorious") dates from the Fatimite conquest in 960 A.D. The location chosen for the town was on high ground near the escarpment of the Moqattam Hills. The course of the main channel of the Nile was then much farther east than now, and the annual flood of the river inundated not only the land between it and the Khaleeg Canal but a wasteland of lagoons and marshes between the canal and the city walls. Although between the ninth and fourteenth centuries the Nile shifted gradually westward to approximately its present position, not until the Khaleeg and the lagoons and marshes had been filled in late in the nineteenth century did the new, west side of the city begin to develop.
Fatimite Cairo was a fortified city enclosed first with a brick wall and later, as it expanded north and south, with a succession of walls of stone. To it the Caliph Mo'izz, for whom Egypt had been conquered from the Tulunid Caliphs, moved his headquarters in 973 A.D. from Kairawan in Tunisia, and from it he claimed under his suzerainty Egypt's most extensive "empire" of all time. The essentially military character of the early city and its strategic position, commanding the valley and delta from the shelter of the Moqattam Hills, were recognized by Saladin. Having ousted the Fatimites in 1171 and founded the Ayyubid Dynasty, he built the famous Citadel in Cairo as his headquarters.
Cairo dates its preeminence as the commercial and industrial center of the country from this period of the Ayyubid Caliphs. Merchants, artisans, and craftsmen of all nationalities and religions were encouraged to settle there and given many privileges. Ayyubid times are still reflected in the craft divisions of the old city - the alleys where goldsmiths, coppersmiths, leather workers, pottery makers, tent makers today ply their ancient trades. The bazaar of the Musky quarter, the mecca of every tourist, hums with activities that stem from that period. For nearly 900 years, however - until the Cairo-Suez railroad was completed in 1856 - Cairo had no connection with Egypt's eastern neighbors except by caravan. Until Mohammed Ali opened his Mahmudiya Canal in 1820 to provide a barge way between the valley and the port of Alexandria, Cairo's only connection with the Mediterranean was by caravan and intermittent barge transport on the Rosetta and Damietta branches of the Nile through the delta. When Ismail (Governor-General 1863-1867 and Khedive 1867-1879) succeeded to the Governor-Generalship, the railroad to Alexandria had also been built and the stage was set for the development of Cairo to become the hub of the country.
Indeed, the growth of modern Cairo may properly be said to date from Ismail's reign. His ambition was to bring his country more closely into the European orbit, and the approaching completion of the Suez Canal made the time especially auspicious for the creation of a city that would impress the visiting dignitaries at the opening festivities.
The deserted marshlands between the Nile and the Khaleeg Canal were filled in with refuse and rubble from the old quarters. Wide avenues were laid out on the reclaimed land and lined with residential palaces and other fine buildings. The government offices were moved to new buildings from the Citadel, where they had been ever since Saladin had first installed his headquarters there. Many of the palaces and monumental construction of present-day Cairo-the Opera House, the house of the Geographical Society, and the road to the Great Pyramids-date from that period. Ismailiya District, planned by Ismail and named for him, is still one of the main business sections of the city.
Ismail's successors followed his example. By the end of the nineteenth century the Khaleeg Canal, which up to 1899 still supplied Cairo with water, was completely filled and the city stretched to the right bank of the Nile. The westward expansion has continued during the present century. The towns of Giza, Doqqi, and Aguza west of the river have been developed and so connected by bridges as to become integral parts of the Cairo metropolis, as are the two islands of Gezira and Roda.
Cairo is today not only the largest city in Africa but the largest in the Arab world. It has grown phenomenally in the last two decades and particularly since World War II.
In no other large city in the world is the history of so great a span of years so clearly visible and in no other are the traditional and the modern, the old and the new, so intricately intertwined. There could scarcely be a greater contrast than that between the modern business districts of Ismailiya and Tewfiqiya and the shops and bazaars of the medieval Musky section; between Garden City, with its well-planned streets lined with houses and apartment buildings, and the old native quarter of Sayeda Zeinab, where thousands of families are crowded in ancient buildings huddled together along tortuously winding alleyways; between Zamelek, a spacious modern residential section on the northern end of Gezira Island, and the teeming town of Bulaq, which faces it across the Nile.
Fast interurban trains and well-paved roads connect Cairo with Heliopolis, Giza, Ma'adi, Helwan, and other suburbs. A few miles northeast of the city is one of the world's most important international airports, and nearby is the Almaza Airport from which Fgyptian-owned airlines fly annually nearly 400, 000 miles in Egypt, carrying upwards of 1,000,000 kilograms of freight and baggage and between 40,000 and 50,000 passengers. But even in the most modern section of the city, freight-laden donkeys and camels, donkey carts and horsedrawn carriages, porters with pushcarts and heavy back loads still mingle with automobiles and motor trucks, and Nile sailing crafts with their pointed lateen sails moor side by side with motor barges. Men of the working classes, in gown and skull cap scarcely to be distinguished from the garb of the rural fellahin, sheiks in striking traditional costume, and even an occasional veiled woman rub shoulders with men and women in clothes that reflect the latest European styles.
Until recently tolerance toward people of other nationalities and religions had long distinguished Cairo from other Arab capitals, and in fact set off Egypt as a whole from other countries of the Arab orbit. The role that Europeans and other outsiders have played in Cairo's development is visible in its numerous foreign quarters, synagogues and churches of many Christian sects, and foreign schools and colleges.
Like most European capitals, Cairo is not only the administrative center of the country but its cultural, financial, commercial, and business center and its leader in industrial development.