The city of Sønderburg in Denmark is situated in one of the most beautiful places of Südjütland on the island of Alsen on the northern shore of the Flensburg bay. Just like many other cities it is characterized by German and Danish past. Sønderburg belonged to Denmark till 1864, after that Germany owned it till 1920. With its 30,000 inhabitants Sønderburg today is not only providing recreation for the local tourists, but has much to offer for the tourists from all over the world.
The castle built in the 12th century now serves as the museum that is the most significant in Südjütland and one of the oldest buildings in the region. To the south of the castle is located a beach. The Old Town is rich in buildings created in the style of modern. The German museum of Nordschleswig informs about the German history of this region. The harbour has a special charm together with an anchor parking of historical ships and a yacht harbour and a starting point of the so-called rum regatta from and to Flensburg.
Some kilometers to the west of Sønderburg is located the information centre of Duppel (Historiecenter Dybbøl Banke). The decisive battle took place here in 1864 during the German-Danish war which ended with Danish defeat.
There are two street bridges together with the drawbridge span the 250-metre-wide Alsen.