Finland Just Joined NATO. But What Is NATO and Why Is It Expanding?

Finland has become the latest North Atlantic Treaty Organization member, known as NATO. The country joined in a brief ceremony on 4 April. Finnish President Sauli Niinistö called it ‘a great day for Finland’. But what is NATO? NATO is an intergovernmental military alliance. It was founded in 1949 by 12 countries, including the US and France, in response to Soviet expansion under Joseph Stalin. When the USSR collapsed in 1991, many former Eastern Bloc states joined NATO. Today, it has 29 European members and 2 North American ones. Under NATO rules, an armed attack on one member is considered an attack on them all. Watch to learn more about what it is and why it is expanding further.