Burgruine Aggstein

Where: Aggsbach Dorf, Austria

Start of construction: 12th Century

End of construction: 16th Century

Accessible: yes

Important fact:

from 1645 onward the decline of the castle started and it slowly became a castle ruin.

The castle lies some 300 meters over the Danube River and was destroyed and rebuilt several times during its existence.

https://www.ruineaggstein.at/en.html