of the Havel. Disguised as a mosque, it was designed by Ludwig Persius. Persius also had plans to extend the theater wall on the Ruinenberg with a high look-out tower, in imitation of a medieval watchtower. After his early death, the so-called Norman Tower was built by Ferdinand von Arnim in 1846. References The information in this article is based on a translation of its German equivalent. External links The Ruinenberg, the Nordic Garden and Sicilian Garden, and the Potentestück The Steam Engine Building The Norman Tower Potsdam from Above – Ruinenberg Geography of Potsdam Buildings and structures in Potsdam Sanssouci Park