If you look back at the time when humans first decided to give up their nomadic, hunter-gatherer lifestyle in favor of settling down at one place, six distinct cradles of civilization can be clearly identified: Egypt, Mesopotamia (present-day Iraq and Iran), the Indus Valley (present-day Pakistan and Afghanistan), China, Mexico and Peru.

These are the regions where our very first cities were built, the expanses where harvesting of crops and raising of livestock first took place, the areas where the first innovations in technology were made, and the places where language was developed and complex social orders came into being.

Since these regions needed to be hospitable and capable of sustaining life, you will notice a common thread between the early civilizations: They all sprung up near rivers. And this development took place around 3000 BCE for each of them except China, who joined the scene only in 2100 BCE.

While this video focuses on the rise of the Incan Empire the underlying ideas can be applied to the other 5 regions mentioned in above text.