The City Wall can be visited
Town Fortification Olpe
The city fortification of Olpe, a historical structure in the Olpe district, is located in the city of Olpe. Although it has undergone changes, remnants of this defensive complex, which once protected the city, can still be visited today.
History+
The origins of the Olpe city fortification likely date back to the period after the city fire of 1373, when reconstruction also included the construction of protective walls and gates. However, another city fire in 1795 led to the demolition of large parts of the fortifications. In the 20th century, specifically between 1957 and 1961, a renovation of the wall at Kurkölner Platz took place, including the round tower located there.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: https://commons.wikimedia.org/wiki/File:Olpe_city_wall.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: 51.0300, 7.8467