The Fortness can be visited
Berliner Tor Fortness (Wesel)

The Berlin Gate in Wesel, built between 1718 and 1722, is the only surviving gate of the former Wesel Fortress complex. Its design in Prussian Baroque style.
History+
The construction of the Berlin Gate took place from 1718 to 1722 under the direction of the fortress and court architect Jean de Bodt. It was part of the Wesel Fortress, whose construction began under Elector Frederick William of Brandenburg and was expanded by Frederick I, the first King of Prussia. King Frederick William I, son of Frederick I, completed the complex in 1722. The gate was renovated in 1791. Although it suffered damage during the defortification between 1890 and 1895 and especially in World War II, its original splendor is still recognizable.
Source: Wikipedia · Licence: CC BY-SA 4.0
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: 51.6572, 6.6222