The Neues Palais, a much larger and grander palace than Sanssouci, stands at the end of the long avenue that runs through Sanssouci Park. It was built after the Seven Years' War (1756–63), when Frederick loosened the purse strings. It's said he wanted to demonstrate that the state coffers hadn't been depleted too severely by the long conflict. Interiors that impress include the Grotto Hall with walls and columns set with shells, coral, and other aquatic decor. The royals' upper apartments have paintings by 17th-century Italian masters. You can opt to tour the palace yourself only on weekends between late April and mid-May.
Str. am Neuen Palais, Sanssouci, Potsdam, Brandenburg, 14469, Germany