Sumer was the first city developed around 3,500 BCE.
Information about paleolithic life is people were Hunters and gatherers, they were nomads (no single home), they used stone and bone tools, and groups were no more than 20-60 people.
The new stone age began about 9,000 BCE when farming was developed. This time was when we started domesticating the animals we have today. The nomadic period ended in this time too. The population increased because people had more food to feed bigger families. Some farming villages even turned into cities.
In some areas of the world people had a dramatic shift in their way of life; the development of civilization. These places saw the development of writing, government, job specialization, and increased technology improvements.