Lisa Cooke (@LisaCooke) tweeted …
Digitized historic Sanborn Fire Maps are available from the Digital Public Library of America … a t: http://pinterest.com/pin/14847873744179015/
At first I was hopeful, but alas only maps from GA, KY (only Frankfurt?), and San Franciso (CA). For genealogists in those locales these are a treasure trove of info about the historic residences.
Library Of Congress – http://www.loc.gov/rr/geogmap/sanborn/
Wikipedia – http://en.m.wikipedia.org/wiki/Sanborn_Maps