Counterterrorism will feature prominently on the United Nations’ agenda this year, as it increasingly has for much of the past two decades since the September 11, 2001 attacks. The organization will be marking the 20th anniversary of the adoption of Security Council resolution 1373, and the 15th anniversary of the elaboration of the UN General Assembly’s Global Counter-Terrorism Strategy. These resolutions set in motion the development of a robust and distinct UN counterterrorism architecture that has continually expanded with new mandates and requests for more resources since then.