1) Big history looks at the progression of human knowledge and society from the formation of the universe to current times. 2) Pursuing knowledge has driven constant technological advances and changes in societies as knowledge defines people's worldviews. 3) Major climate changes like volcanic eruptions in the 6th century CE disrupted many societies and helped shape subsequent world history. 4) Factors like geography, climate, and available plants and animals gave Eurasian civilizations advantages that allowed them to dominate other parts of the world.