The roman Watchtower can be visited
Roman Watchtower 14/4

The Upper Germanic-Rhaetian Limes, with a length of 550 km, from Eining near Regensburg to Rheinbrohl on the Rhine, is the largest archaeological monument in Germany and has been recognized by UNESCO as a World Heritage Site. Limes (Latin: border path/wall) refers to the border fortifications of the Roman Empire, which were erected towards the end of the 1st century AD.
This border was monitored by more than 900 towers, which were built in timber construction during the initial phase, starting around 80 AD. Stone towers followed, which were plastered from 150 AD onwards. Excavations have shown that the white plaster often had cracked joints, which were painted in terracotta. This created the impression of beautiful ashlar masonry.
The tower, unusually large at 4.7 x 6.3 m, re-examined, conserved, and partially reconstructed by the Bavarian State Office for Monument Preservation in 1980, stood dominantly on the ridge and offered a wide panoramic view. The ring wall, on which Wp 14/4 is located, dates back to prehistoric times and is thus considerably older than previously assumed by earlier research.
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: 49.1168, 10.7719