Terrorism Terrorism -- 40 Prevention 17 Prevention -- 7 Terrorists 7 Weapons of mass destruction 7 World politics -- 7 more ... Security, International 6 War on Terrorism, 2001-2009 6 Political violence 5 Forecasting 4 Radicalism 4 Terrorists -- 4 War on terrorism, 2001- 4 Foreign relations -- 3 History 3 History -- 3 International cooperation 3 Moral and ethical aspects 3 Disasters 2 Fanaticism 2 Influence 2 Liberalism 2 Psychological aspects 2 Psychology 2 September 11 Terrorist Attacks, 2001 2 September 11 Terrorist Attacks, 2001 -- 2 Social aspects 2 Violence 2 Accidents 1 less ...