The former city fortifications now form a green belt around the old town and contribute significantly to Überlingen's special flair. This impressive testimony to its imperial past has evolved into an inner-city green belt of high ecological importance and a local recreational area with a unique experience.
Developed over several centuries, the first phase of the city moat system probably dates back to the 12th century. During the Thirty Years' War, the fortifications successfully withstood onslaughts and sieges by the Swedish army twice. Today, the city moat, which consists of several sections, is a true gem of Überlingen and is popular with walkers. Especially in high temperatures, the city moats offer a shady spot.
A variety of plants and animals can be found there, and Europe's largest owl species, the eagle owl, regularly nests in a rock crevice. The rocky outcrops in the city moat provide ideal living and nesting conditions for the eagle owl pair, albeit unusually close to humans. In June 2010, the first Überlingen eagle owl left its nesting site in the city moat, and since then, Überlingen has had chicks every year.
In preparation for the 2021 State Garden Show, various "green spaces" are being interconnected, including the city moats. These are attractive connecting elements, but they also hold great historical value in the city.