The Großer Wannsee (Greater Wannsee) is a bight of the Havel river near the locality of Wannsee and Nikolassee (in the borough of Steglitz-Zehlendorf), a south-western suburb of the German capital Berlin not far from Potsdam. At its borders is located the island of Schwanenwerder and, opposite from the Greater Wannsee on the other side of the Havel, is the locality of Kladow (in Spandau).
The Wannsee lake is well known as the number-one bathing and recreation spot for western Berlin, especially from a 1951 Schlager hit by teen idol Cornelia Froboess. The Strandbad Wannsee, an open-air lido with one of the longest inland beaches in Europe and a popular nudist area, was built in 1920-1930 after a concept by architect Richard Ermisch. Situated on the eastern shore of the lake it is officially part of the Nikolassee locality.