The document provides an introduction to world history, including key terms and concepts. It discusses how the oldest human fossils were found in Africa by Louis and Mary Leakey and Donald Johanson. It also outlines some of the biggest achievements in world history, such as the invention of tools, language, and wheels. Additionally, it introduces the four early river valley civilizations that arose around 3500 BCE in Mesopotamia, Egypt, the Indus Valley, and China due to fertile land and water resources. Key terms related to these early civilizations are also defined.