From earliest times waterways have provided the readiest means of getting about.  All that was needed was a hollow log, a raft, a primitive canoe.  Movement by land was impeded by mountains, deserts, forests, swamps, water courses.  Movement by water was a natural.

More and bigger boats required shelter against storms and protection against destruction by enemies.  A good harbor with an adjacent walled town or city was the answer to this need.

Good harbors and navigable waterways are notably absent along the west coast of South America and notably present in the Eastern Mediterranean.  Consequently, the South American West Coast line is sparsely settled to this day, while the Eastern Mediterranean has been crowded with peoples, teemed with trade and commerce, carried largely by sea, between cities that occupied the best access to waterways.

Safe harbors and navigable waterways made trade and transport easy and cheap.  As each wave of human advance turned from animal husbandry and agriculture to bourgeois practices of industry, commerce and finance, locations at strategic points along trade routes were first occupied by occasional markets and fairs and eventually by trading towns and cities.  Geography was a decisive factor.

Fertility was equally important.  In the early stages of social development transportation was difficult, dangerous and expensive.  Sources of food and building materials were found within a short distance of the growing trade center.  Again geography played a decisive role.  A deep, sheltered harbor backed by a desert could not attract and support a thriving trade center.  Food and raw materials are indispensable to concentrations of human beings.

The Nile Valley, like that of the Ganges and the Yellow River, provided the fertility and transport, the food and raw materials that have sustained concentrated human populations for many thousands of years, forming part of the base for Egyptian, Indian and Chinese civilizations.  Animal husbandry and grain farming, coupled with fishing and forestry, made possible the growth of cities and laid the foundations for the nuclei of these civilizations.

Temples, tombs and other public constructs provided the centers around which Egyptian civilization was built.  The stone, wood and other raw materials used in the building of these unique examples of human handiwork were floated up and down the Nile from their sources of origin.  Annual Nile floods provided silt deposits necessary to fertilize farms and gardens.  Nile water, impounded during floods, irrigated the land during the long dry seasons.  Banked by deserts, the Nile was a ribbon of fertility running through a largely uninhabited wilderness.  The upper reaches of the Nile lay in the mountains of Central Africa.  The Nile delta, built up through ages by silt deposits, provided a meeting place where African, European and Asian traders could exchange their wares and lay the foundations for the civilization of lower Egypt.  The Nile also provided the means of communication which connected Lower Egypt with Upper Egypt and led, finally, to the unification of the two areas in a long enduring and prestigious Egyptian civilization.  Once again geography was laying down the guide lines within which civilizations have been built up and liquidated.