Founded on 4.4.1949 by
Belgium,
Denmark,
France,
Great Britain,
Ireland,
Italy,
Canada,
Luxembourg,
the Netherlands,
Norway,
Portugal and the
USA as a collective defense union.
Greece and
Turkey joined 1952,
West Germany 1955,
Spain 1982,
Poland,
Czech and
Hungary 1999.
"The heart of the North Atlantic Treaty and thus of the NATO alliance is Article 5, in which the signatory members "agree that an armed attack against one or more of
them in Europe or North America shall be considered an attack against them all;" by britannica.com
The NATO was formed as a counterweight to the Soviets.
It is lead by the North Atlantic Council with consists of representaries of the member states.
In 1999 the NATO fought its first war, an air war against Yugoslavia.
Official Homepage http://www.nato.int