This imposing tower standing over the Schuldturm bridge used to guard the crossing. Later on, its role was to provide a secure place to hold the mentally ill. Eventually, it was turned into a debtor's prison. It is said that those passing the tower could hear the screams of those imprisoned inside.
Wikipedia (German) https://de.wikipedia.org/wiki/Schuldturm_%2528N%25C3%25BCrnberg%2529
Coordinates 49°27'9.71" N 11°4'51.396" E