Which countries joined NATO and which ones joined the Warsaw Pact?

NATO, established in 1949, originally included the United States, Canada, and several Western European nations such as the United Kingdom, France, and Italy. Countries that joined the Warsaw Pact, formed in 1955 as a response to NATO, included the Soviet Union, Poland, East Germany, Czechoslovakia, Hungary, Romania, and Bulgaria. Over time, NATO expanded to include many former Warsaw Pact countries after the Cold War, while the Warsaw Pact was dissolved in 1991.