This is a great tweet and link:
The link is to a figure-ground map of Paris that allows you to filter its buildings by period of construction. Here’s what all of the periods and all of the buildings look like:
Once you play around with the map, it will become obvious that the second half of the 19th century and the early 20th century was a prolific building period for Paris (1231 hectares of area). This is what Samuel was getting at in his tweet.
I would love to see a map like this for every city in the world.
BRANDON DONNELLY 
Fascinating, and I too would like a similar map for every major city. Even better though if the colours were better differentiated – with a mind not just to architecture or history but to social issues I can’t be sure about the age of expansion of the banlieus, with the huge slab developments beyond the peripherique that may have been built with the best of intentions have been used as a dumping ground for the poor and dispossessed and therefore unsurprisingly have given rise to a great many social problems. The colours from 1940 until you get to the bright green and yellow of post 2000 are too similar.
And of course no-one with an eye to heritage will be surprised that the ‘real’, desirable, expensive Paris is largely pre 1850.
LikeLike