With the exception of the contribution in World War II by the Soviet Union, China, and the Italian resistance movement, communism was seen as a rival, and a threat to western democracies and capitalism for most of the twentieth century.[citation needed] This rivalry peaked during the Cold War, as the world's two remaining superpowers, the United States and the Soviet Union, polarized most of the world into two camps of nations. This was characterized in the West as The Free World vs. Behind the Iron Curtain. It supported the spread of their economic and political systems, capitalism vs. communism, and strengthened their military powers. As a result, the camps developed new weapon systems, stockpiled nuclear weapons, and competed in space exploration. They even fought each other through proxy client nations.[citation needed]

network type
alternative energy