The terrorist attacks of September 11, 2001, reshaped the world far beyond the day itself. The ensuing “War on Terror” transformed warfare and intelligence operations, expanded surveillance and the use of drones, and raised fundamental questions about torture, human rights and the rule of law. At the same time, 9/11 fuelled racism, radicalisation and conspiracy theories, while contributing to growing distrust in political institutions and the media. From the wars in Afghanistan and Iraq and Guantánamo to the rise of right-wing populism and increasing political and social division, the long-term consequences of 9/11 continue to shape global politics and society today.