President Obama and British Prime Minister David Cameron meet children at Mount Pleasant Primary School in Newport, South Wales, on Thursday. / Christopher Jones, epa
NATO is holding a closely watched summit in Newport, Wales, Thursday and Friday.
NATO - the North Atlantic Treaty Organization - was established in 1949 to act as a counterweight to the threat of militant European nationalism and to encourage political integration.
Here are some facts that you may not know about the Brussels-headquartered organization.
1. It is a political and military alliance of 28 member countries from Europe and North America.
2. The greatest responsibility of the alliance is to protect and defend NATO's territory and populations. NATO's Article 5 states that an attack on one member is an attack on all. Article 5 has been invoked only once in NATO's history, on Sept. 12, 2001, the day after the 9/11 attacks on the U.S.
3. NATO has a permanent, integrated military command structure where military and civilian personnel from all member states work together. U.S. Air Force General Philip Breedlove is NATO's top military officer.
4. NATO defends airspace over Albania, Estonia, Latvia, Lithuania and Slovenia on a 24/7 basis, 365 days per year.
5. Member countries make direct and indirect contributions to the costs of running NATO and implementing its policies and activities. NATO wants all members to contribute at least 2% of their respective GDPs to defense spending. Only a handful of members do that. The U.S. and U.K. are among them.
6. The alliance's deterrence strategy is currently based on a mix of nuclear and conventional capabilities. However, NATO Secretary General Anders Fogh Rasmussen wants the alliance to evolve to become a "faster, fitter and more flexible" fighting force able to deploy its military assets at short notice into a variety of military situations.
7. In 1995, NATO helped to end the war in Bosnia-Herzegovina and implement the peace agreement there. In 1999, NATO helped to stop mass killings and expulsions in Kosovo, and NATO troops continue to serve in Kosovo under a United Nations mandate.
8. NATO has a global network of security partners from over 40 countries. Among these are the United Nations, the European Union, the Organization for Security and Cooperation in Europe and the African Union. Ukraine, the location of ongoing tensions with Russia, is not a member of NATO, but it wants to be. Russia opposes the idea.
9. Four other countries currently aspire to NATO membership: Bosnia-Herzegovina, Georgia, Montenegro and the former Yugoslav Republic of Macedonia.
10. Collectively, NATO members comprise at least 50% of the world's total GDP and can call on over 3 million men and women on active service.
Read the original story: NATO fact sheet: 10 things to know