Are there any projects in the vein of Geograph, OSM, Yelp, or Wikipedia for people remembering and preserving images and information about cities, city blocks, buildings? Particularly for cities that are damaged by disaster or war, this seems like a valuable thing to do at the granularity of "the unit that individuals photograph, remember, share with one another".
It would be good to have a freely-licensed structural history of a city in this fashion, block by block. And something that refugees from a crisis could do to preserve areas they frequented.