1940s: World War II pits the major European powers against each other, with axis powers Germany and Italy, and later Japan, on one side and allied powers Britain, Russia and later the U.S. on the other. The entry of the United States into the war in 1941 tips the scales in favor of Britain and its allies.

Today: The main European combatants of World War II are steadily moving toward more and more economic and political integration through the European Union. In January 2002, twelve European countries, including France and Germany, adopt a single currency, the Euro.

1940s: Radio and newspapers are the media through which people get their information. Communication is via telephone, letters, and, in urgent cases, telegrams.

Today: Television has replaced the newspaper as the principle source of information for most people. The Internet is a rapidly growing resource for news and...