The Warsaw Pact.
The Warsaw Pact was given that name because the agreement was signed in Warsaw, Poland. Established in 1955, the Warsaw Pact included the Soviet Union, Albania, Poland, Romania, Hungary, East Germany, Czechoslovakia, and Bulgaria as members. The nations signing the treaty called on each other to defend of any member of the Pact that was threatened by enemy forces. The formation of the Warsaw Pact was in direct response to the formation of the North Atlantic Treaty Organization (NATO).