NATO:

• NATO, established in April 1949 through the North Atlantic Treaty, is a military alliance formed by the United States, Canada, and various Western European nations to ensure collective security against the Soviet Union.
• The alliance currently consists of 30 member states.
• Original members include Belgium, Canada, Denmark, France, Iceland, Italy, Luxembourg, the Netherlands, Norway, Portugal, the United Kingdom, and the United States.
• Greece and Turkey joined in 1952, followed by West Germany in 1955 (later referred to as Germany from 1990), Spain in 1982, and the Czech Republic, Hungary, and Poland in 1999.
• Further expansions occurred in 2004 with the inclusion of Bulgaria, Estonia, Latvia, Lithuania, Romania, Slovakia, and Slovenia, and in 2009 with Albania and Croatia joining.
• Montenegro became a member in 2017, followed by North Macedonia in 2020.
• France withdrew from NATO's integrated military command in 1966 but remained a member, resuming its position in NATO's military command in 2009.
• Recently, Finland and Sweden have expressed interest in joining NATO.
• NATO's headquarters is situated in Brussels, Belgium.

The headquarters of Allied Command Operations is located in Mons, Belgium.