The first people to inhabit the earth lived more than two million years ago. They survived by hunting, fishing, and wild plants. They were forced to move from place to gathering place in the pursuit of food. The development of agriculture around 10,000 BCE ended this nomadic way of life and gave rise to the first civilizations. When people learned how to grow crops and domesticate animals, they were able to settle in one place. Settlements g into villages and eventually into cities. People began to work specialized jobs, develop arts and crafts, and participate in other activities of civilized ife. They formed governments and invented systems of writing. By 3500 BCE, the world's first civilizations emerged in the fertile valleys of the Tigris-Euphrates, Nile, Indus, and Huang He rivers.