1949: The North Atlantic Treaty Organization is founded to create an alliance between the United States and nations of Western Europe in opposition to the military might of the Soviet Union in much of Eastern Europe.

1955: The Warsaw Pact forms a military alliance between the Soviet Union and other Eastern European nations.

1963: The Nuclear Test Ban Treaty, signed by the United States, the Soviet Union, and the United Kingdom, bans the testing of nuclear weapons in the earth's atmosphere, in outer space, and underwater; it limits the testing of atomic weapons to underground sites.

1967: The Outer Space Treaty is signed by the United States, the Soviet Union, the United Kingdom, and other nations; it declares that space exploration be conducted for peaceful purposes only and that no nation may claim sovereignty over the moon or any other region of outer space.

1968: The Nuclear Non-Proliferation Treaty...