Terrorism is defined as the unlawful use of violence or threats to intimidate or coerce governments, organizations, or societies in pursuit of political, religious, or ideological goals. It has a long history dating back thousands of years and has taken various forms throughout history from individuals and groups to states. Modern terrorism emerged in the late 19th century and has increasingly been used by religiously-motivated groups in the last 20 years of the 20th century. Terrorism is a form of asymmetrical warfare and propaganda that aims to achieve political objectives through psychological means of spreading fear.