From the Wikipedia page 
Plön (German pronunciation: [ˈpløːn]) is the district seat of the Plön district in Schleswig-Holstein, Germany, and has about 8,700 inhabitants. It lies right on the shores of Schleswig-Holstein's biggest lake, the Great Plön Lake, as well as on several smaller lakes, touching the town on virtually all sides. The town's landmark is Plön Castle, a chateau built in the 17th century on a hill overlooking the town.
Plön has a grammar school with a 300-year history, and is home to a German Navy non-commissioned officer school and the Max Planck Institute for Evolutionary Biology. The town, nestled as it is in the hilly, wooded lake district of Holstein Switzerland (Holsteinische Schweiz), also has importance in the tourism industry.