Where: Dresden, Germany
Constructed: 1709-1732
End of construction: 1855
Most important renovation: 20th Century
Accessible: yes
Important fact:
The Zwinger, originally a wooden orangery, has been damaged several times in its existence (last time in 2002) or destroyed (last time in 1945), but has been repaired or rebuilt
over and over again.
https://www.der-dresdner-zwinger.de/en/home/