The North Atlantic Treaty Organization, commonly known as NATO, is an intergovernmental military alliance established on April 4, 1949, through the signing of the North Atlantic Treaty (also known as the Washington Treaty). It is headquartered in Brussels, Belgium, and currently has 32 member states from North America and Europe. NATO was founded with the primary purpose of ensuring collective defense. According to Article 5 of the treaty, an armed attack against one member is considered an attack against all, obligating allies to respond collectively. This principle has been invoked only once in NATO’s history, following the September 11, 2001 terrorist attacks in the United States.
The organization plays a crucial role in international security by conducting crisis management operations, supporting conflict prevention, and enhancing the military capabilities of its members. NATO has participated in various missions including those in the Balkans, Afghanistan, Iraq, and Libya.

Under Secretary General: Deniz Nur Berk