BINNENALSTER

The 'Binnenalster' (meaning "inner Alster") is one of two artificial lakes within the city limits of Hamburg, Germany, which are formed by the river Alster (the other being the Außenalster).
The phrase "inner" refers to the old city walls of Hamburg. The Binnenalster was the part of the lake that was "inside" the city walls. The lake was originally created to serve as a reservoir for a mill.
Today the old city walls do not exist, instead two car and train bridges, the Lombardbrücke and the Kennedybrücke, span the river.
The Alstervergnügen festival is held around the Binnenalster.