By war, we mean a social phenomenon that has its distinctive feature in the armed violence carried out between states, governments, societies, or paramilitary groups such as mercenaries, insurgents, and militias.

Archaeological evidence indicates that war has been part of human life since the dawn: according to past theories, it was assumed that the first nomadic peoples (hunter-gatherers) were more peaceful than their sedentary counterparts (growers) of the following years, but the findings mass burial sites around the world have led researchers to review this theory.