[OT from cottage renovations]
[crossposted from Google+]
Sanborn fire maps are a familiar tool to anybody who has ever needed a times series of historical maps for some location. Mapping the as-built conditions was intended to provide a baseline for any claim adjudication, valuation and reconstruction that might might follow a natural (or unnatural) disaster. Periodic updates and secure storage made them a natural for other historical purposes.
These UK before-and-after news images show an interesting use of GSV imagery for the same purpose.
(click past these samples for interactive before-and-after imagery)
[edit: added link to wiki page]