NATO
Participating countries
NATO has thirty members, mainly in Europe and North America. Some of these countries also have territory on multiple continents, which can be covered only as far south as the Tropic of Cancer in the Atlantic Ocean, which defines NATO's "area of responsibility" under Article 6 of the North Atlantic Treaty. During the original treaty negotiations, the United States insisted that colonies such as the Belgian Congo be excluded from the treaty. French Algeria was however covered until their independence on 3 July 1962. Twelve of these thirty are original members who joined in 1949, while the other eighteen joined in one of eight enlargement rounds.
NATO-30