"An attack on one is an attack on all." This is the basic principle, Article 5, in NATO's statutes. In this film, you will learn more about NATO, which was formed in 1949 by twelve nations from North America and Western Europe as a defence alliance against the Soviet Union, which shortly after NATO's founding formed the Warsaw Pact. Members of NATO pledged never to start a war against each other, but instead to defend their nations with collective strength. Over the years, and especially since the end of the Cold War in 1991, more countries have joined. The film explains how decisions are made within the organisation through consensus in the North Atlantic Council, which is NATO's decision-making body. Finally, the film discusses that the function of NATO is often debated and questioned, since the member countries have very different political, economic, and military conditions.