Jadebusen
The Jade Treaty () of 20 July 1853 between Kingdom of Prussia and Grand Duchy of Oldenburg provided for the handover of 340 hectares of Oldenburg territory at what is now Wilhelmshaven, Germany, on the western shore of the Jade Bight, a bay of the North Sea west of Bremerhaven. It was considered the best natural deep-water port in the German North Sea coast, and a good place for the naval base Prussia wished to build. The navy base built there became the nucleus of today's Wilhelmshaven.