Prince Elector Johann Wilhelm had a straight avenue built from the palace courtyard to Heidelberg in 1748. Under Prince Elector Carl Theodor, the road lined with mulberries became the key element in the new baroque design of the summer residence and the “New Town”. It runs directly from Königstuhl, a hill in Heidelberg, via Schwetzingen palace garden - in part as a sight line - to the Kalmit, the highest elevation in the Palatinate Forest. This axis served as the base line (Basis Palatina) for court astronomer Christian Mayer when he surveyed the Electoral Palatinate.