The North Atlantic Treaty Organization (NATO), also called the North Atlantic Alliance, is an intergovernmental military alliance and a collective security system, in which its member states agree to defend each other against attacks by third parties.
NATO was originally founded in August 1949 by 12 member states: Belgium, Canada, Denmark, France, Iceland, Italy, Luxembourg, Netherlands, Norway, Portugal, the United Kingdom, and the United States of America. As of today, NATO has 32 member states, with Sweden joining the alliance in March 2024.