Animal violence
Throughout the book, Harari uses violent imagery to underscore the brutality with which Homo sapiens have dealt with animals. After humans shifted away from their hunter-gatherer ways, they started to domesticate animals and grow crops for sustenance, staying in one place. This imagery underscores humanity's tremendous power and their ability to dominate every part of the world they are in as they attempt to survive.
Groups of humans
One of Harari's theses is that Homo sapiens were able to survive and thrive because they are the only animal that is able to cooperate in large groups. Throughout his book, Harari uses imagery of large groups to underscore this point, often showing how groups of people (including nations) work together towards a common goal. He specifically points to the United States, where groups of seemingly different people worked together towards a common goal ("Life, Liberty, and the Pursuit of Happiness").
Industry
When describing human advancement, Harari describes the industrial revolution, when humans built large factories to make new products more efficiently. As a result of the factories, smog and pollution spewed from the factories, dirtying the cities they were in and harming human beings. Harari describes things like thick smoke and terrible smells in great detail, underscoring not only the transformative nature of the change, but the deleterious effects industry and the industrial revolution had on people.
Religion
After Homo sapiens developed the ability to imagine things, Harari hypothesizes they created religion. Throughout the book, there is frequent religious imagery to show the role religion has played in Homo sapiens lives.
