The Electors and Landgraves of Hesse-Kassel spent their "summer retreat" in the over 200-year-old Wilhelmshöhe Castle. Today, it is a museum for significant art and cultural collections.

Landgrave Wilhelm IX commissioned the construction of Wilhelmshöhe Palace as the centerpiece of his mountain park. Originally, it consisted of three separate buildings. Later, Elector Wilhelm II had these buildings connected to each other. This is how the palace acquired its current closed and solid appearance.

The imperial family used Wilhelmshöhe Palace as a summer residence until 1918. It was heavily damaged during World War II and gradually rebuilt after 1945. Today, the left wing serves as an administrative building. The central section houses unique collections such as the Old Masters Picture Gallery. The museum in the right part of the building (White Stone Wing) is currently being restored and usually displays historically furnished rooms of the Landgraves.