to the Nazi's battle to burn as much "degenerate art" as they could find
The "degenerate art" removed from the museums headed in all sorts of directions,
- Sold on the international markets to raise money for the Reich
- vanished into private hands - Cornelius Gurlitt's collection resurfaced as recently as three years ago
- vanished into private hands and then was destroyed in allied bombing raids
- destroyed by the Nazis
Hitler used to use Baedeker travel guides as a guide to what should be destroyed, although a famous library in the Netherlands was bombed at the start of the war "just because". After the Allies (ok, the British) destroyed a few German cultural spots of neglible military value, the Luftwaffe was sent to destroy highlights selected from Baedeker such as Coventry Cathedral.
There were two Warsaw uprisings, the Jewish one and then later - with the Soviets approaching - the Polish one. As revenge for the second one, buildings were blown up in the order of their ranking in the Warsaw Baedeker - best to worst. The Soviets ceased their advance and waited for the Nazis to suppress the uprising before resuming operations. That is one of the factors behind the Polish attitude to Russia, Katyn being another big one.
With ISIS (I thought it was ISIL) now starting to operate in Saudi Arabia, I wonder if Islamic sites are in danger. One would think not but I had not expected the recent suicide bombings either.