Hohensalzburg

Where: Salzburg, Austria

Start of construction: 11th Century

End of construction: 16th Century

Accessible: yes

Important fact:

With a width of 150 meters, a length of 250 meters and a total area of 7,000 m², this is one of the largest castle complexes in Europe.

https://www.salzburg-burgen.at/en/hohensalzburg-castle/