There is a movie about post-war Warsaw [1], based on Russian airplane photo shoots. The part of the city that looks almost perfectly flat is the former Jewish ghetto. Nowadays, this area has a completely different arrangement of streets, because in 1945 you could not tell very well a street from a building, so it was re-engineered.

[1] https://www.youtube.com/watch?v=Vx3aGiurRbQ

Stalingrad 1942 vs 2013: http://fpvestnik.ru/foto/stalingrad-194243-volgograd-2013/

Take a look at the second picture on this page:

http://culture.pl/pl/artykul/co-pamieta-warszawa

This is the ghetto area.

And these are before/after photos, all taken in the center of Warsaw: http://wczorajidzis.blogspot.com/2010/06/3-w-1-1945-1971-201...

I've always been hoping that we can learn from past mistakes, but recent inaction of western europe towards Putin's war with Ukraine has me deeply worried.