The Belvedere (1789-90), a charming construction by Carl Gotthard Langhans, served at one point as the "tea house" of Frederick William II for the spiritualist meetings, of which he was a great fan. It is depicted by a simple façade in white and pastel tones, the style of which is more neo-Classical than Rococo. The building houses a small museum of the Royal Berlin Porcelain Factory which charts the history of the Berlin porcelain industry of the 18C and 19C.