The Wilhelmsthal Park is located away from the hustle and bustle of the city in the municipality of Calden and offers relaxation in a fairytale atmosphere. Wilhelmsthal Castle and its garden with elaborate flower beds provide the backdrop for popular open-air events such as the Kassel Garden Festival.

Wilhelm VIII commissioned the construction of Wilhelmsthal Palace as a pleasure and hunting palace in the Rococo style from 1743. It is located - rather unusually - at the lowest point of the park. The Rococo garden landscape. was never completely finished. An impressive grotto building with water features from that time has been preserved. Landgrave Wilhelm the Ninth had the park transformed into a landscape garden. On a hill, the Warttum was also built as an artificial medieval ruin. From the tower, one has a wonderful view of the surroundings.