The river-side city wall of the southern suburb was secured by two round towers; on one side we can name the Red Tower and on the other the Tower of Haus Schönburg.
The name of the tower already indicates that in its area once the city palace of the Schönburg family was located.

The round tower is centrally positioned on the city wall, allowing the walkway to run right through the tower. The round-arched walkways on both sides are still visible today. It has a diameter of just under six meters. Additionally, this tower, at a height of nine meters, is also smaller than the other towers on the river-side city wall.
Inside the tower, there is a small stone staircase leading to the defense platform. From the outside, the tower is adorned on the upper floor or at the defense platform by a round arch frieze made of light sandstone and a crenellation above it with sloped arrow slits. Noteworthy are the pointed arched windows added later on the river side as well as the octagonal battlement of the observation platform, which connects above the round arch frieze on lime sandstone consoles.

Source: Kira Bublies, University of Koblenz-Landau, 2016