Annaberg Castle

Schloss Annaberg is referred to as a castle-like manor house located at Annaberger Straße 400 in the Bonn district of Friesdorf. The building is situated in the western part of the village in a wooded area that transitions into the Kottenforst forest. It is currently used as a meeting place and is a listed building.
Since the 18th century, alum-containing lignite and clay have been extracted in the area from the Marienforst monastery - as was the case on Pützberg, which was sold in 1807, where the Friesdorf lignite, alum ore, and vitriol ore mining operation began in 1808. After several changes of ownership, the mines were abandoned in 1845, and the landscape was re-natured and afforested by Franz Moll. Above the then-village, the Annaberg experimental farm was established in the second half of the 19th century on the former mining site, after the Prussian government acquired the land in 1860. The experimental farm was part of the Agricultural Academy Poppelsdorf. The estate included an agricultural school and a tree nursery, which opened in 1865 after the closure of the Cologne Central Tree Nursery. By 1875, the academy had ceased its activities on the estate.

Wikipedia