The bright yellow walls of the Orangery Palace in Karlsaue are visible from afar. Today the building houses the Cabinet of Astronomy and Physics with its world-renowned historical measuring instruments and clocks as well as the largest Planetarium in Hesse.
Early in the 18th century the maison de plaisance built by Landgrave Wilhelm IV (r. 1567 –1591) was converted into a stately orangery palace at the behest of Landgrave Carl (r. 1677–1730). The central block with the two flanking pavilions – the kitchen quarters and the Marble Bathhouse – are situated at right angles to the layout of the surrounding Karlsaue park, with the main facade facing south.
The central pavilion housed the so-called Apollosaal, while numerous orange and laurel trees wintered in the long connecting wings. The pavilions at either end were used by the Landgrave and his spouse as a summer residence. Five more pavilions were planned along the same axis, but during Carl's lifetime, only one of them – the Marble Bathhouse – was actually built. The kitchen pavilion at the opposite end was only completed in 1770.
In WWII, parts of Karlsaue were destroyed. The Orangery burned down, but the Marble Bathhouse survived. The Federal Garden Show of 1955 provided an impetus to restore and redesign those stretches of park in the vicinity of the palace; in 1959, the Orangery ruins provided the setting for documenta II. On the occasion of the second Federal Garden Show to be held at Kassel in 1981, and with the Orangery already rebuilt, the bowling green to the west of the palace was restored to a Baroque layout.