The Museum Island is a museum complex on the northern part of the Spree Island in the historic heart of Berlin, Germany. It is one of the capital's most visited sights and one of the most important museum sites in Europe. Originally, built from 1830 to 1930, by order of the Prussian Kings, according to plans by five architects, the Museum Island was designated a UNESCO World Heritage Site in 1999 because of its testimony to the architectural and cultural development of museums in the 19th and 20th centuries. It consists of the Altes Museum, the Neues Museum, the Alte Nationalgalerie, the Bode-Museum and the Pergamonmuseum. As the Museum Island designation includes all of Spree Island north of the Karl Leibniz avenue, the historic Berlin Cathedral is also located there, next to the open Lustgarten park. To the south of Leibniz avenue, the reconstructed Berlin Palace houses the Humboldt Forum museum and opened in 2020. Also adjacent, across the west branch of the Spree is the German Historical Museum. Since German reunification, the Museum Island has been rebuilt and extended according to a master plan. In 2019, a new visitor center and art gallery, the James Simon Gallery, was opened within the Museum Island heritage site.

The Spree is, with a length of approximately 400 kilometres (250 mi), the main tributary of the River Havel. The Spree is much longer than the Havel, which it flows into at Berlin-Spandau; the Havel then flows into the Elbe at Havelberg. The river rises in the Lusatian Highlands, that are part of the Sudetes, in the Lusatian part of Saxony, where it has three sources: the historical one called Spreeborn in the village of Spreedorf, the water-richest one in Neugersdorf, and the highest elevated one in Eibau. The Spree then flows northwards through Upper and Lower Lusatia, where it crosses the border between Saxony and Brandenburg. After passing through Cottbus, it forms the Spree Forest, a large inland delta and biosphere reserve. It then flows through Lake Schwielochsee before entering Berlin, as Müggelspree (pronounced [ˈmʏɡl̩ˌʃpʁeː] ).