Terrorist attacks and terrorism have become major global problems. Between 1961 and 2003 the US Department of State documented 228 acts of worldwide terrorism (DiMaggio and Galea 2006). Since 2003 there have been numerous terrorist attacks in more than 50 countries worldwide (Global Terrorism Index 2015). The single biggest terrorist attack has been the September 2001 (9/11) World Trade Center attacks in New York City in which almost 3000 people were killed.