The remains of the fortress can be visited
Fortress Magdeburg-Wittenberger Eisenbahntor
The Wittenberg Railway Gate is a historic fortress structure in Magdeburg, Saxony-Anhalt.
Magdeburg's first fortifications can be traced back to the 13th century. Between 1450 and 1550, extensive modernizations took place, including the construction of a second city wall and the fortification of the Elbe front. These installations proved effective during sieges in the 16th and 17th centuries. Rebuilt under Prussian rule after its destruction in the Thirty Years' War, Magdeburg developed into one of Prussia's strongest fortresses.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:Magdeburg_Wittenberger_Eisenbahntor.JPG
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: 52.1362, 11.6519