The complex includes Wilhelmshöhe Palace (with the Antiquities Collection and Old Masters), the Hercules monument, and the Lions Castle. Wilhelmshöhe Palace above the city, was built in 1786 by landgrave Wilhelm IX of Hesse-Kassel. The palace is now a museum and houses an important collection of Graeco-Roman antiques and a fine gallery of paintings comprising the second largest collection of Rembrandts in Germany. It is surrounded by the beautiful Bergpark Wilhelmshöhe with many appealing sights. The complex was named a UNESCO World Heritage Site in 2013.
The Hercules monument is a huge octagonal stone structure carrying a giant replica of Hercules "Farnese" (now at Museo Archeologico Nazionale in Naples, Italy). From its base down to Wilhelmshöhe Palace runs a long set of artificial cascades which delight visitors during the summer months. Every Sunday and Wednesday afternoon at 14:30 (from May until October) the famous water features take place. They start at the Oktagon and during a one-hour walk through the park visitors can follow the water's way until they reach the lake of the castle Wilhelmshöhe, where a fountain of about 50 metres (160 ft) marks the end of the spectacle.
The Löwenburg ("Lions Castle") is a replica of a medieval castle, also built during the reign of Wilhelm IX. After the Franco-Prussian War of 1870/71 Napoléon III was imprisoned in Wilhelmshöhe. In 1918 Wilhelmshöhe became the seat of the German Army High Command (OHL): it was there that the military commanders Hindenburg and Ludendorff prepared the German capitulation.