of any kind. During the Pax Britannica, America developed close ties with Britain, evolving into what has become known as a "special relationship" between the two. The many commonalities shared with the two nations (such as language and history) drew them together as allies. Under the managed transition of the British Empire to the Commonwealth of Nations, members of the British government, such as Harold Macmillan, liked to think of Britain's relationship with America as similar to that of a progenitor Greece to America's Rome. Throughout the years, both have been active in North American, Middle Eastern, and Asian countries. Late 20th century After the Second World War, no armed conflict emerged among major Western nations themselves, and no nuclear weapons were used in open conflict. The United Nations was also soon developed after World War II to help keep peaceful relations between nations and establishing the veto power for the permanent members of the UN Security Council, which included the United States. In the second half of the 20th century, the USSR and US superpowers were engaged in the Cold War, which can be seen as a struggle between hegemonies for global dominance. After 1945, the United States enjoyed an advantageous position with respect to the rest of the industrialized world. In the Post–World War II economic expansion, the US was responsible for half of global industrial output, held 80 percent of the world's gold reserves, and was the world's sole nuclear power. The catastrophic destruction of life, infrastructure, and capital during the Second World War had exhausted the imperialism of the Old World, victor and vanquished alike. The largest economy in the world at the time, the United States recognized that it had come out of the war with its domestic infrastructure virtually unscathed and its military forces at unprecedented strength. Military officials recognized the fact that Pax Americana had been reliant on the effective United States air power, just as the instrument of Pax Britannica a century earlier was its sea power. In addition, a unipolar moment was seen to have occurred following the collapse of the Soviet Union. The term Pax Americana was explicitly used by John F. Kennedy in the 1960s, who advocated against the idea, arguing that the Soviet bloc was composed of human beings with the same individual goals as Americans and that such a peace based on "American weapons of war" was