This web page, created by the Library of Congress, provides general background information on wide range of subjects, including Art, Politics, Economy, History, National Security and much more . Good place to learn basic facts or background information.
Also, check Bibliography provided on this site for further reading on different subjects.
(* "The 'Portals to the World' Web project was taken down on September 16, 2010 in order to perform a comprehensive review of its content." The following links are preserved for possible future use, but they do not work currently).
Provides links to various internet resource on wide range of subjects, including: