- The North Atlantic Treaty Organization is an intergovernmental military alliance based on the North Atlantic Treaty which was signed on 4 April 1949.
- The NATO headquarters are in Brussels, Belgium
- The September 2001 attacks signalled the only occasion in NATO's history that Article 5 of the North Atlantic treaty has been invoked and consequently the 11 September attacks were deemed to be an attack on all nineteen NATO members
- After 11 September, troops were deployed to Afghanistan under the NATO-led ISAF and the organization continues to operate in a range of roles sending trainers to Iraq, assisting in counter-piracy operations and most recently enforced a NATO-led no-fly zone over Libya in 2011 in accordance with UN SC Resolution 1973.
- The Berlin Plus agreement is a comprehensive package of agreements made between NATO and the European Union on 16 December 2002. With this agreement the EU was given the possibility to use NATO assets in case it wanted to act independently in an international crisis, on the condition that NATO itself did not want to act—the so-called "right of first refusal".
- The combined military spending of all NATO members constitutes over 70% of the world's defence spending. The United States alone accounts for 43% of the total military spending of the world and the United Kingdom, France, Germany, and Italy account for a further 15%.
- The proposed American missile defence site in Central Europe is expected to be fully operational by 2015 and would be capable of covering most of Europe except parts of Romania plus Bulgaria, Greece and Turkey.
- In response, Russian Prime Minister Vladimir Putin claimed that such a deployment could lead to a new arms race and could enhance the likelihood of mutual destruction. He also suggested that his country would freeze its compliance with the 1990 Treaty on Conventional Armed Forces in Europe (CFE)—which limits military deployments across the continent—until all NATO countries had ratified the adapted CFE treaty.
- NATO formed the NATO Training Mission – Iraq, a training mission to assist the Iraqi security forces
- NATO comprises 28 members: Albania, Belgium, Bulgaria, Canada, Croatia, Czech Republic, Denmark, Estonia, France, Germany, Greece, Hungary, Iceland, Italy, Latvia, Lithuania, Luxembourg, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Turkey, the United Kingdom, and the United States.