War is an organised and often prolonged armed conflict that is carried out by states or non-state actors. It is characterised by extreme violence, social disruption, and economic destruction.[1][2] War should be understood as an actual, intentional and widespread armed conflict between political communities, and therefore is defined as a form of political violence or intervention.[1][3] The set of techniques used by a group to carry out war is known as warfare. An absence of war is usually called peace.