The town, nestled as it is in the hilly, wooded lake district of Holstein Switzerland (Holsteinische Schweiz), also has importance in the tourism industry.

In the course of the Migration Period, Slavic tribes entered the region of Plön during the early 7th century following the withdrawal of the original Germanic population.

In 1139 the Count of Holstein, Adolf II of Schauenburg, destroyed the fortress, ending the domination of the Slavs in the region of Plön.

It was here, under the protection of the castle and close to the major trading route from Lübeck to the north, that a Saxon market town emerged.

Strategically located on a narrow isthmus between the lakes and the River Schwentine, Plön remained a centre of the County of Holstein until the Danish royal house fell in the 15th century.

At that time the town had about 1,000 inhabitants and reached as far as the bridge over the Schwentine in the east and as far as the end of today's pedestrian zone in the west.

In the mid-19th century, the Danish crown prince spent a few years of his summer vacation in Plön Castle, since when it has been decorated in white plaster with a gray roof.

After the end of World War II, former NAPOLA pupils were often able to avail themselves of a form of ‘evasive selective memory’ that ultimately cast themselves as victims of the Nazi regime, and allowed them to make their own (sometimes very successful) way in postwar society.

[4] In 1891 Emil Otto Zacharias founded the first "Biological Station" for freshwater research on German soil on the Plöner See.

Hitler believed that Reichsfuhrer SS Heinrich Himmler was located in Plön and ordered newly appointed Luftwaffe commander Robert Ritter von Greim to fly there to arrest him.

On 1 May, Commander of the Navy, Admiral Karl Dönitz, moved into the buildings of the Stadtheide Barracks but it was to be a short stay.

After WWII Plon was chosen as the site for King Alfred School, a secondary school for British Forces children under the headmastership of Freddie Spencer Chapman with his staff at the Ruhleben Barracks site, As such the town holds a place of affection with many former pupils across the world and the declining number of surviving teachers and their families.

Parts of Günther Fielmann's own antique collection can be viewed at the castle; it encompasses pieces from the major north European and French epochs since the mid-seventeenth century.

It was previously used as a summer house and was given its present name when the sons of the last German Emperor, William II were taught in this building.

For example, there is on the Princes' Island, a thatched pavilion, from where there is a view of the Great Plön Lake - this was a favourite haunt of the Empress.

On Plön's Planet Walk the solar system is mapped on a scale of 1:2,000,000,000, starting from a symbol of the sun on the landing stage on Market Bridge.

Ute Krieglstein designed the yarn dolls, including the set and plays songs, composed by her, with her husband, Gerd, who is responsible for the technology.

The little town nestles, surrounded by lakes, on a narrow strip of land encircling the low hill, whose heights are occupied by the old ducal palace, ringed by old trees, avenues and terraced, sloping gardens.

Around the sprawling waters of the lakes, which can be seen from above in a single sweeping gaze, runs a belt of beautiful beech forest over serries of hills, interspersed with a gay, fertile landscape.

When, in the evening of a bright summer's day, the moon casts its beams over the gently stirring waves of the lake surface, what a wonderful decoration to play romantic games with the heart over the terraces and under the old trees…" ~ Rochus von Liliencron, 1902, in his Jugenderinnerungen ("Memories of Childhood")