To be privately owned
Knonau Castle

In the Canton of Zurich, Switzerland, Knonau Castle stands as a former bailiff's castle. Its history dates back to the 13th century, although the current structure originates from the 16th century. It is known for its architecture and the plane trees at its entrance.
History+
The origins of the estate date back to 1240, when a manor farm was first documented. In 1507, Zurich relocated the seat of a bailiwick to Knonau, and just five years later, the city acquired the jurisdiction along with the manor farm. Around 1525, the castle was built as the seat of the bailiff and underwent expansions in the following decades, including walls and a moat. In the 18th century, the castle was redesigned, with the main entrance relocated and new outbuildings added.
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: 47.2228, 8.4643