The Residential Palace Darmstadt is the former residence and administrative seat of the landgraves and from 1806 to 1919 of the Grand Dukes of Hesse-Darmstadt. It is located in the centre of the Hessian city of Darmstadt.
Today the castle is the seat of the Technische Universität Darmstadt and the German-Polish Institute.
Wikipedia https://en.wikipedia.org/wiki/Residential_Palace_Darmstadt
Address 15 Marktplatz, Darmstadt 64283, Germany
Coordinates 49°52'25.132" N 8°39'18.14" E