The document discusses the key characteristics and achievements of early civilizations. It describes the first civilizations as forming along major rivers like the Nile, Tigris/Euphrates, Indus, and Yellow River and developing cities, governments, social hierarchies, religions, writing systems, and cultural productions like art. The major early civilizations discussed are ancient Mesopotamia, Egypt, the Indus River Valley civilization, ancient China, and Mesoamerican civilizations. Each developed complex cultures with their own achievements in areas like architecture, mathematics, engineering, and calendar systems.