Evidence of early civilizations has been uncovered by archeologists. Neolithic people in Mesopotamia, now roughly Iraq, Kuwait and Syria, swapped nomadic hunter–gatherer lifestyles for life in villages, near which they grow crops and keep livestock. These settlements attract vermin, insects and parasites, and the denser populations that they support encourage infectious diseases to emerge. Many animal pathogens, including those that cause tuberculosis and smallpox, make the jump to humans. The best known civilizations first emerged in the great river valleys of Asia, Egypt and Mesopotamia about 6 thousand years ago emerged along the Nile, Sumeria between the Tigris and Euphrates, in the Indus valley of India and in China, along the yellow river. South East Asia was a centered of agricultural development and a place of convergence of migratory groups. The common element of early civilizations was the development of agriculture in the fertile valleys and adjacent lands that produced food surpluses and wealth, first expressed as food stores that could be bartered and sold. Populations grew larger, cities emerged, trade links were established with other groups and cultures developed.
Growth of human populations intensified during the Holocene, as domestication centers in the Near East, Egypt, China, Mexico and Peru underwent expansions commencing about 10,000 years ago. From these centers, population growth spread into Europe, South America, North Africa, South Asia, Southeast Asia, and Australasia during the succeeding 6,000 years. Sub-Saharan Africa has no archeological evidence for agriculture before 4,000 years ago; the population of sub-Saharan Africa was likely less than 7 million people, compared with European, West Asian, East Asian, and South Asian populations approaching 30 million each. Increasing concentrations of people had benefits and liabilities that continue today. In about 100 AD Roman poet, Juvenal wrote of the “thousand perils” that are faced by those who live in ancient Rome; fire, collapsing buildings, infection, sewage and noise .
City states acquired rulers and myths based on the claims of rulers to be Gods or, at least, the human envoys of Gods. Rulers were supported by priestly castes and armies who confirmed the divine status of rulers and obtained the obedience of subjects. Human sacrifice was popular in all these settlements. The folly of Egyptian pharaohs is well known; for several centuries they were preoccupied with preparations for an imaginary life after death. The pharaohs of the pyramid era could assemble workers by the hundreds of thousands and build ever more grandiose monuments for themselves. Pyramids were death monuments with accommodations, not only for the Pharaoh’s mummified corpse, but also for wives, family, friends, servants and favorite animals who were buried alive with his corpse. The sacrifice of large numbers of people with dead rulers also appeared in Sumeria and China. While human civilizations have left some interesting stories and artifacts, real human history involves endless repetitions of cruelty, slavery, war, death and destruction. Most humans were not and still are not nice, peaceful creatures who respect human rights.
( Stephanie Pain. The Rise of the Urbanite. Nature 531, S50–S51 17 March 2016)