Schloßinsel

The castle is located opposite the Köpenick city center with the Köpenick town hall on an island in the Dahme, not far from its confluence with the Spree. The island is connected to the mainland by a bridge over the moat. In the immediate vicinity is the Long Bridge, which crosses the Dahme and connects the old town of Köpenick as well as the Castle Island and the Castle with the newer districts to the west and north-west and the center of Berlin.
Source: Wikipedia

Especially in summer there are also great events here... I think in September there will also be a pop party... Always a lovely atmosphere and great people

From the outside you can see the great location. Inside, it's about handicrafts from the Baroque era and its marriage to the Rococo.