Wilhelmshaven , Mer du Nord , Basse-Saxe , Allemagne

Port d’Allemagne sur la Mer du Nord , allez-y plutôt en été !

The Siebethsburg castle , built before 1383, operated as a pirate stronghold; the Hanseatic League destroyed it in 1433. Four centuries later, the Kingdom of Prussia planned a fleet and a harbour on the North Sea. In 1853, Prince Adalbert of Prussia, a cousin of the Prussian King Frederick William IV, arranged the Jade Treaty (Jade-Vertrag) with the Grand Duchy of Oldenburg, in which Prussia and the Grand Duchy entered into a contract whereby Oldenburg ceded 3.13 km2 (1.21 sq mi) of its territory at the Jade Bight to Prussia. In 1869 King William I of Prussia (later also German Emperor) founded the town as an exclave of the Province of Hanover and a naval base for Prussia’s developing fleet. All the hinterland of the city remained a part of Oldenburg.