Plön castle stands on a hill above the lake and the town, a pale, solid, rather formal building that looks as though it was designed to impress someone, which it was. Duke Joachim Ernst of Schleswig-Holstein-Plön had it built in the early seventeenth century, and the dukes of Plön lived here until their line ran out in the eighteenth century, when the Danish crown took over. Later it became a Prussian military school, and today it is a private boarding school, so you can look at the exterior and the terraced gardens but not walk through the rooms.
What matters most to a rider is the setting. The castle sits on a ridge between two lakes, the Great Lake of Plön and the smaller Lake of Plön, and the view from its edge covers islands, reed beds and forested shores. The town's streets slope down towards the water, and the old centre has some good half-timbered houses and a pleasant market square. Plön is a town of about thirteen thousand, which means it has fuel, supermarkets and several cafés.
The roads around here are some of the best in Holstein, with long, curving lanes that follow the lake shores and climb the low glacial hills. The hills, left by the Ice Age, are gentle but numerous, so the riding has a rolling, rhythmic quality, with the occasional sharp bend at the bottom of a dip. In summer, the lakes fill with sailboats and swimmers, and the roads fill with cyclists and day-trippers, so the early morning and the evening are best. Spring brings fields of rape and blossoming orchards.
Ascheberg and Bösdorf, both just five kilometres away, are small lakeside villages with swimming spots and small restaurants serving fresh fish. Try the local smoked fish if you see it. Pull in at the car park by the lake for a few minutes, and the view will explain why people have been building castles here for four hundred years. Stay for the sunset if you can, because the lake turns copper.