( View map )The map seems to date from around 1930; among the differences it shows from the present is that one of the canals I cycle along on the way to work, the Neuköllner Schifffahrtskanal, is reduced to a mere ditch, the Wiesen Graben, which, instead of connecting to the Landwehrkanal at its western end, originates instead at a pool labelled Wiesen Br[?unnen].
This is interesting, because the curve where the former bank of the Landwehrkanal ran, and where it now turns into the Schifffahrtskanal, is precisely the point where the iced-over section of the canal (i.e. the Schifffahrtskanal, but not at all the Landwehrkanal, which I didn't until I got this map realise was even a separate canal) began last winter.
I still don't know the reason why. Maybe the Schifffahrtskanal is shallower; maybe there's less flow along it.
You can see other interesting differences in the bit of map I'm posting here: present-day Sonnenallee and Karl-Marx-Straße were then Kaiser Friedrich Straße and Berliner Straße; the interesting thing about the latter of these is that it was in _west_ Berlin, i.e. it wasn't the communists who renamed the street after Marx!
(The other notable difference that you can't see on this segment of map is that there were lots more synagogues than there are today. :-()
I wonder what the lack of grey for built-up areas towards the outskirts of the city mean. Surely they couldn't have laid out so many streets with no houses yet? And surely Berlin can't have grown so much since just 1930?