I wonder if it would be possible to generate street view like navigation of the world decades ago by geolocating photos. Could we reconstruct a 1920s city for example?
In popular areas with lots of overlapping photos, something akin to that was possible with PhotoSynth where it joined together matching photos projected into an inferred 3D space. Sadly the service was discontinued a while back.
Compare with one of my favourite maps of all times, the Turgot Map of 1730s Paris. The full-res image is worth the giant download, it's a lot of fun to just pan around.
The publisher Blondel la Rougery made a modernized one, I had a poster version from a mid-nineties copy of the French GEO magazine, now misplaced. Sadly they went out of business shortly afterwards, and the map seems out of print.
Here is a 1953 version from the Rumsey collection:
Theres some similar data from Montreal. I once made a draggable map out of a bunch if 1947 aerials a long time ago, but the hosting/dns screwed up when i moved the domain. Oh well.
In 1970 a massive project crowdsourced thousands of photographs of everywhere in Paris (nearly every single grid square on each letter sized page, a rare few have no photos).
To see the photos, click on a map section to go to the subgrid page. Then find the square grid number that corresponds to where you want to see and click the corresponding numbered link from the list at the top.
There's a pretty great article here in English, full of details about this collection of over 30k amateur photographs: Catherine E. Clark, "'C’était Paris en 1970': Amateur Photography, Urbanism and Photographic History"
