A primate of this period, at ease both in the trees and on the ground, is probably the common ancestor of gorillas, chimpanzees and humans

Various species of ape develop the habit of walking upright on two feet

Certain primates, in eastern and southern Africa, are by now sufficiently like humans to be classed as hominids

A female of the species Australopithecus Afarensis (nicknamed Lucy when her skeleton is found), lives in the Afar Depression in Ethiopia within 50 miles of where her predecessor Ardi was unearthed

A Homo erectus boy, aged about ten, lives near Lake Turkana in Kenya and dies at Nariokotome

Painted and engraved images, on the rock face in a cave near Twyfelfontein in Namibia, date from this period

The Sahara, damp enough for the hippopotamus, supports neolithic communities until it begins to dry up in about 3000 BC

The first evidence of a loom comes from this period in Egypt, but some simple method of holding the warp must be as old as weaving

A simple hand-held plough is in use in Egypt and Mesopotamia, at least 1000 years before a heavier version is pulled by oxen

Upper and Lower Egypt are unified into a single kingdom, inaugurating the first Egyptian dynasty

The Egyptians paint murals on the walls of tombs, designed to help the occupants in the next world

The Egyptian hieroglyphic script develops at much the same time as the Sumerian cuneiform

The pharaoh Narmer celebrates a victory with a sculpted relief showing his personal dominance over the enemy

An easily portable writing surface is developed, from the papyrus plant of the Nile

The lever is in use in both Mesopotamia and Egypt

The ass, until now roaming wild from northeast Africa to Mesopotamia, is domesticated in Egypt

The earliest known currency, consisting of gold bars, is in use in Egypt and Mespotamia

The world's earliest known board game, senet, is played in Egypt

Sirius rises in this year on the first day of the first Egyptian month - a rare event which possibly launches the Egyptian calendar system

Imhotep creates the first pyramid - the 'step pyramid' at Saqqara - as a tomb for the pharaoh Djoser

Egypt enters the period known as the Old Kingdom, its first era of monumental architecture

The first and largest of the three great pyramids at Giza is built for the pharaoh Khufu, later known to the Greeks as Cheops

A boat of cedar planks, some 44 metres long, is buried at Giza

The largest sculpture of the ancient world, a sphinx with the face of the pharaoh Khufu, is carved in situ at Giza

To preserve bodies in perpetuity, the Egyptian ruling class develops the elaborate and lengthy process of mummifying an eviscerated corpse