I can spend days rummaging around the US Library of Congress website. The early colour photography is fantastic and the occupational pictures, always my first call, are fascinating. The site can be tricky to manoeuvre at first and the items come up in list form but there is a GALLERY option which makes searching easier. There are also oral history recordings of ordinary people's memories, freed slaves, folk musicians and eyewitness accounts of history for example, which add an extra dimension to character study.
Remember to search with American English - color being the most obvious difference.
