Aussenalster, or the Outer Alster Lake, is the larger of the two Alster lakes located in Hamburg. It was formed in the 13th century by damming the Alster River. At the time, it was outside of the city walls, which is how it became known as the Outer Alster Lake. The Inner Alster Lake was within the city walls. The lake is almost 400 acres large but no more than about eight feet deep. In order to maintain the charm and beauty of the area, it is a rule that all buildings surrounding the lake must be white and their roofs must be covered with copper.
The Outer Alster Lake is a popular place for boating activities. You can rent sail boats, canoes, kayaks, paddle boats, and rowboats at many locations. There are also several boat tours available on the lake. Many people also enjoy jogging or walking around the lake, which is about four and a half miles around. There are also parks where you can have a picnic, sunbathe, or relax in an Alsterchair. All along the shores, you can find restaurants and cafes where you can have a meal or a drink with a view of the lake.
The Outer Alster Lake is separated from the Inner Alster Lake by the Kennedy Bridge and the Lombard Bridge. The lake is located in the northern part of the city, north of both the Inner Alster Lake and Hamburg's main train station.