Where: Heidelberg, Germany

Start of construction: 13th Century

End of construction: 17th century

Most important renovation: 19th Century

Accessible: yes

Important fact:

Destroyed in 1689 and 1693 and struck by lightning in 1764, causing the castle to become a ruin. At the end of the 19th century the castle was partly restored and partly kept ruined.

https://www.schloss-heidelberg.de/en/home