The Lower Pond is a large artificial pond in northern Kaliningrad, Russia. It was known as the Schlossteich while part of Königsberg, Germany, until 1945.
The pond is about one kilometre long, north to south. Along its length, its width varies between about 50 and 100 metres. The source of the water is from the north. The water eventually drains underground down to the river Pregel to the south. During the winter months, the pond can freeze over.
Wikipedia https://en.wikipedia.org/wiki/Lower_Pond_(Kaliningrad)
Address (Unnamed Road), Калининград, Russia
Coordinates 54°42'54.248" N 20°31'1.654" E