People appeared on Earth between 5 and 7 million years ago. The period of history from this time until people started writing is Prehistory. There are three periods of Prehistory: the Palaeolithic, the Neolithic and the Age of Metals. The Palaeolithic Period started about 2.5 million years ago. At this time, people hunted animals for food, caught fish and collected fruit. They were nomads, so they moved around a lot, living in huts or caves – there were no villages, towns or cities. The Palaeolithic people discovered fire and they made tools from stone. About 10,000 years ago, the Neolithic Period began. People started growing food and keeping animals, so they stopped moving around. Instead, they had a quiet lifestyle. They built houses, lived in villages and stayed in one place for many years, perhaps their whole lives. During this time, they invented the wheel, sails for boats, farming tools and pottery. The Age of Metals began at different times in different parts of the world, when the people in a place discovered how to make tools from metal. In ancient Greece and China, the Age of Metals began before 3000 BCE, but in Britain it started after 2000 BCE. Making tools from metal helped people grow food and build things more easily. When a culture started writing, their period of prehistory ended. After prehistory, we can use records, like books and letters, to find out what life was like for people in the past.