Potsdam, is the capital city of the German federal state of Brandenburg. It directly borders the German capital Berlin and is part of the Berlin/Brandenburg Metropolitan Region. It is situated on the River Havel, southwest of Berlin's city center.Potsdam was a residence of the Prussian kings and the German Kaiser, until 1918. Around the city there are a series of interconnected lakes and cultural landmarks, in particular the parks and palaces of Sanssouci, the largest World Heritage Site in Germany. The Potsdam Conference, the major post-World War II conference between the victorious Allies, was held at another palace in the area, the Cecilienhof.Babelsberg, in the south-eastern part of Potsdam, was a major film production studio before the war and has enjoyed success as a major center of European film production since the fall of the Berlin Wall. The Filmstudio Babelsberg is the oldest large-scale film studio in the world.Potsdam developed into a centre of science in Germany from the 19th century. Today, there are three public colleges, the University of Potsdam and more than 30 research institutes in the city.