1914: The assassination of archduke Franz Ferdinand, heir to the Austrian throne, sets off a chain of political events that draws most of the countries of the world into the First World War.

1985: Many of the countries that had formerly been in the Austro-Hungarian empire before the start of World War I are members of the Soviet Union.

Today: After the Soviet Union's dissolution in 1991, some countries are struggling to cope with independence and establish their own identities.

1914: Feminist Margaret Sanger is forced to leave the United States for England to avoid prosecution for printing her pamphlet, "Family Limitation," which dealt with the subject of birth control.

1985: U.S. abortion rights, which were established by the Supreme Court in the 1973 decision in Roe v. Wade, constitute one of the most talked-about political issues. Candidates for national offices endure tremendous pressure to declare themselves supporters for...