The history of the Hildebrandt mansion in Osieki dates back to 1924. The mansion was built by Carl Hildebrandt, whose grandfather purchased the villages of Osieki, Rzepkowo and Kleszcze in 1838. Built in the heart of an English park, the Osieki mansion is a half-timbered structure with rich wooden ornaments. The owners lived there until 1945; after World War II, the mansion was converted into an apartment building for the workers of the local State Agricultural Farm. Ruined during the period of martial law in Poland, it was eventually purchased by a private investor in the 1990s and rebuilt into a hotel.