Human beings evolved in Africa over millions of years and slowly spread across continents as hunter-gatherers. During the Old Stone Age (Paleolithic Age) from 500,000 BCE to 4,000 BCE, early humans were nomadic, subsisting as hunter-gatherers who used crude stone tools and weapons, lived in caves or natural shelters, and wore clothing made of animal skins or plant materials. They created some of the earliest art in vivid cave paintings between 40,000-35,000 BCE, and accidentally discovered how to control and use fire which provided protection and allowed cooked food.