Terrorism is often defined as unlawful violence or systematic use of terror against civilians or politicians for ideological or political reasons, with the intention to create fear. Terrorism is practiced by nationalistic groups, religious groups, revolutionaries and ruling governments.
The fear of terrorism is still instilled in many people's minds. According to Gallup’s survey, which was conducted among adults in the United States in 2013, 34 percent of the participants stated that they were very worried about the possibility of future terrorist attacks. Only 10 percent of the participants said that they were not at all worried.