Social Science
United States Census: http://www.census.gov/
C.I.A. World Factbook: https://www.cia.gov/library/publications/the-world-factbook/index.html
United Nations: http://www.un.org/en
United States Presidents: https://www.whitehouse.gov/1600/Presidents
BBC Historic Figures (archived page): http://www.bbc.co.uk/history/historic_figures/a.shtml
Library of Congress Prints and Photographs Online Collection: http://www.loc.gov/pictures/
U.S. Department of State: http://www.state.gov