Where: Sankt Johann, Germany
Start of construction: 12th Century
End of construction: 17th Century
Accessible: yes, interior with guide
Bürresheim was a double castle, where two noble families shared and expanded the castle. One part, the Trier Castle, has been perfectly preserved. The other, the Kölner Castle, is a ruin.
This is due to the fact, that in 1659, the Trier castle was expanded and the Köln section became less and less used and important.
The Trier section is accessible; the ruin not.