The earliest humans were hunter-gatherers. Hunter-gatherer societies were nomadic out of a necessity to survive, as farming had not yet been invented. Hunter-gatherers would survive by foraging and hunting for food. This required hunter-gatherer societies to be mobile in order to follow the animals they hoped to hunt. These hunter-gatherer societies make up the majority of the time of human history.
Around 10,000 BC, humans experienced the Neolithic Revolution, in which they invented farming and learned to domesticate animals. It is believed that the first area of the world to experience the Neolithic Revolution was the Fertile Crescent, located in the area around the Tigris and Euphrates rivers.
With the invention of farming and the domestication of animals, human history changed significantly. Societies became permanent, because people had to stay in one spot to tend to their crops. The invention of farming and animal domestication also led to greater production of food and required less manpower to do so. This meant that fewer people were required to be involved in food production, and those not involved in food production were able to undertake other tasks. With greater food production, populations grew, and more tasks necessary to society (aside from food production) were accomplished.
With the invention of farming, early human societies developed in river valleys. River valleys provided water necessary for farming to be successful. Humans did, however, further improve their odds of success by modifying their environments. In the earliest farming societies, there is evidence of people creating irrigation canals to ensure water reached their farmland and also evidence that they attempted to build dams and barriers to prevent flooding. Since the Neolithic Revolution, humans have become masters of adapting and altering their environment in order to thrive in very diverse areas of the planet.