This link will take you to the home page of the American Memory Historical Collections of the Library
of Congress.
Hint: Go to collection finder and select “History”, then
pick a category. I particularly
like “Western US Photographs 1860 – 1920”.
This gives you access to the collection “History of the American West,
1860-1920: Photographs from the Collection of the Denver Public Library”. Also check out the
Railroad Maps Section and the Depression to WWII Photographs Section. Caution
– this is a very addictive site! But, as a taxpayer, you own it -- so go
ahead and take a look.