1957: First military nuclear power plant is dedicated at Fort Belvoir, Va.

1965: Australia announces it will send troops to Vietnam

1970: 50,000 U.S. and South Vietnamese troops invade Cambodia

1974: President Richard Nixon agrees to release the Watergate tapes

1975: The Vietnam War ends after more than 20 years of conflict

Sources: www.history.com; www.scopesys.com