The ‘war on terror’ became a popular slogan in the United States after the 9/11 attacks. The reaction against ‘Islamist terrorism’ has profoundly influenced not only American politics, both nationally and internationally, but also European policies. Since then the struggle against the terrorist threat has often been used by Western governments to pass legislation that, according to many observers, has reduced the freedom of citizens in the name of security. Today, however, the world scenario has changed again and completely. The economic crisis begun in 2007 has dramatically influenced the priorities of governments, the perception of citizens and has been the driver of geopolitical shifts in North Africa. The killing of Bin Laden in Pakistan (May 1, 2011) appropriately marked the end of an era. What is the legacy of these ten years? 9/11 has placed emphasis on four major trends in Europe. Historically, the Islamist terrorist has favoured the rise of a common idea of who is a terrorist. Politically, the fight against terrorism has turned out to be one of the most advanced models of EU cooperation. Philosophically, the necessity of preventing terrorist attacks has paved the way to the concepts of threat and risk, which have compressed criminal justice in favour of a more discretionary ‘crime prevention’. Technologically, risk management calls for new technologies to be effective. Coherently, since 9/11, the EU has allocated resources to combat terrorism that have been spent mainly to develop technologies for the control and prevention of attacks. This chapter deals with each of those trends in order to take stock of the European experience and to imagine future developments.