1962: The Cuban missile crisis in October makes the threat of global nuclear war seem an imminent possibility.

Today: The Cold War over, the United States no longer faces the consolidated military strength of a communist rival. The Berlin Wall, a powerful symbol of Cold War division, fell m 1989. The fear of nuclear war is no longer as great, although there exists widespread concern about the spread of nuclear technology to terrorist groups or so-called "rogue states."

1962: Cold War competition with the Soviet Union affects many aspects of American life. In space, prior Soviet achievements are matched by the U.S. this year, as Col. John Glenn achieves the first U.S. Earth orbit and the U.S. launches its first satellite, Telstar.

Today: The Soviet Union no longer exists as such, first withdrawing its control over the Eastern Bloc countries, and then fragmenting into...