The remains of the Castle can be visited
Blankenburg Castle

The Blankenburg castle ruin, a lowland castle, is located in Uckerland-Wolfshagen in the Uckermark region. Its strategic location on the former border between Brandenburg, Mecklenburg, and Pomerania made it a stronghold during times of regional conflicts.
History+
Around 1250, the castle was built by the von Raben family on an island in the Haussee lake. Its position on the border gave it military importance in the disputes between Brandenburg, Mecklenburg, and Pomerania. As early as 1392, it is documented that the Lords of Blankenburg were vassals of the Margrave of Brandenburg.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:Wolfshagen_Blankenburg.jpg?uselang=de
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 53.4419, 13.6496