The River Spree flows through which European capital city?

Berlin is the capital and largest city of Germany by both area and population, and its 3,711,930 (2017) inhabitants make it the second most populous city proper of the European Union after London. The city is one of Germany's 16 federal states, and it is surrounded by the state of Brandenburg, the capital of which, Potsdam, is contiguous with Berlin. The two cities are at the center of the Berlin/Brandenburg Metropolitan Region, which is, with 6,004,857 (2015) inhabitants, Germany's third-largest metropolitan region after the Rhine-Ruhr and Rhine-Main regions.

Berlin straddles the banks of the River Spree, which flows into the River Havel (a tributary of the River Elbe) in the western borough of Spandau. Among the city's main topographical features are the many lakes in the western and southeastern boroughs, formed by the Spree, Havel, and Dahme rivers, the largest of which is Lake Müggelsee. Due to its location in the European Plain, Berlin is influenced by a temperate seasonal climate. About one-third of the city's area is composed of forests, parks, gardens, rivers, canals and lakes. The city lies in the Central German dialect area, the Berlin dialect being a variant of the Lusatian-New Marchian dialects.