Mesopotamia and Egypt: 3100 BC
In about 3200 BC the two earliest civilizations develop in the region where southwest Asia joins northeast Africa. Great rivers are a crucial part of the story. The Sumerians settle in what is now southern Iraq, between the mouths of the Euphrates and the Tigris. Egypt develops in the long narrow strip of the Nile valley.
Rivers offer two main advantages to a developing civilization. They provide water to irrigate the fields, and they offer the easiest method of transport for a society without paved roads. Rivers will play an equally important role in two other early civilizations - those of the Indus and of northern China.
The Indus: 2500 BC
This vast eastern empire seems set apart from the rest of the world, fiercely proud of its own traditions, resisting foreign influences. Its history begins in a characteristically independent manner.
There are no identifiable precedents for the civilization of the Shang dynasty, which emerges in China in about 1600 BC. Its superb bronze vessels seem to achieve an instant technological perfection. Its written texts introduce characters recognizably related to Chinese writing today. This is a civilization which begins as it will continue - with confidence.
America: 1200 BC
Around this time the earliest American civilizations have their beginnings, with the Olmecs in central America and the Chavin in the Andes.
Both these cultures develop large towns, centred on temples. Both are now famous for their sculpture. And each, in its own region, is at the start of a succession of civilizations leading directly to the two which are discovered and destroyed in the 16th century by the Spanish - the Aztecs in central America and the Incas in the Andes.
The Mediterranean: from 1000 BC
The first distinctively Mediterranean civilization, that of the Aegeans, comes to a sudden and still unexplained end in around 1200 BC. Some 200 years later an energetic seafaring people, the Phoenicians, become extensive traders. From their base in Lebanon they establish colonies along the coast of Africa and even into the Atlantic.
Their example, as Mediterranean imperialists, will be followed by the Greeks and then by the Romans. The Mediterranean becomes the world's most creative arena for the clash and synthesis of civilizations - a status which it has never entirely lost.
Regional civilizations: AD 400 - 1500
With the dominance of Greece and Rome in the west (both successfully managing a transition from pagan to Christian empires),...