Some truely amazing photos on the American Library of Congress Flickr pages. They've put up thousands of images. You could spend hours on here. Probably the best flickr account I've come across yet.
Flickr: Photos from The Library of Congress
Delano, Jack,, 1914-, photographer.
Children in the tenement district, Brockton, Mass.
1940 Dec.
Downey, Jack,, photographer.
Crowds of French patriots line the Champs Elysees to view Allied tanks and half tracks pass through the Arc du Triomphe, after Paris was liberated on August 25, 1944
1944 Aug. 25
Lee, Russell,, 1903-, photographer.
Scrap and salvage depot, Butte, Montana
1942 Oct.