The Ruinenberg is a landscaped hill at the northern edge of Sanssouci Park, topped with an artfully designed fake Roman ruin — columns, arches, and fragments arranged as if the remains of an ancient temple had been discovered there. Frederick the Great built it in 1748 as a picturesque folly visible from the park below, in the English landscape tradition of constructed ruins. The hill also served as the reservoir for the park's fountains, though the pump that was supposed to fill it never worked properly.
The Ruinenberg is one of the less-visited spots in the park and worth seeking out. The view from the hill takes in the entire length of Sanssouci Park from east to west, with the Orangerie, the Sanssouci palace, and the Neues Palais all visible in sequence. At the bottom of the hill on the park side, the Sicilian and Nordic Gardens — two small formal gardens laid out by Frederick William IV in the 1840s — offer a quiet detour on the walk back.