1850s: The United States embraces the concept of "Manifest Destiny," a phrase coined in an article in the July-August, 1845, issue of United States Magazine and Democratic Review. The phrase imparts the view that It is God's will that the young nation expand across the continent. In the resulting expansion, settlers race west to California in search of gold in 1849.

1997: Although no longer claiming that expansionism is God's will, the United States continues to explore new frontiers. U.S. astronauts work side-by-side with their Russian counterparts aboard the Russian space station Mir in an effort to investigate the prospects of long-term cooperation in space.

1850s: American society at large perceives gambling at cards and other games of chance, in which money changes hands, as the domain of drifters, con-men, and prostitutes.

1997: Casino gambling is no longer confined to Las Vegas or Atlantic City, having come...