Library of Congress Digital Collections
"The Library of Congress has made digitized versions of collection materials available online since 1994, concentrating on its most rare collections and those unavailable anywhere else. The following services are your gateway to a growing treasury of digitized photographs, manuscripts, maps, sound recordings, motion pictures, and books, as well as "born digital" materials such as Web sites. In addition, the Library maintains and promotes the use of digital library standards and provides online research and reference services. (from LOC website).