Martin Luther King
http://www.webcorp.com/civilrights/martin.htm
Audio clips from the I Have a Dream speech

Martin Luther King, Jr., Papers Project
http://www.stanford.edu/group/King/
Primary and secondary materials about the civil rights leader.

The Cuban Missile Crisis, 1962
http://www.gwu.edu/~nsarchiv/nsa/cuba_mis_cri/cuba_mis_cri.html
A detailed chronology of the crisis, with some documents and photographs.

The Sixties Project
http://lists.village.virginia.edu/sixties/
Scholarly articles and primary source documents cover American involvement in Vietnam.