
On 23 June 2013, the total work of art of Wilhelmshöhe was listed as a World Cultural Heritage site by UNESCO's World Heritage Committee, an act that distinguished it as a cultural landscape that is unique: Nowhere else in the world was a place like this ever created: a park on a steeply sloping hillside featuring huge, artistically and technologically accomplished water structures such as those built at Kassel from 1691 onwards by Landgrave Carl and his successors.
The World Heritage property is about 560 ha in size, extending from the famous Kassel landmark – the Hercules Monument – via the 350-m Cascades down towards Wilhelmshöhe Palace and beyond it along the visual axis of Wilhelmshöher Allee.
The beginnings of the park design go back to the 1680s. The park extends from the monumental Hercules building over the 350 meter long cascade down to Wilhelmshöhe Palace and beyond. The landscaped garden is one of the largest in Europe and is a unique cultural monument. Wilhelmshöhe Palace in the park served the landgraves and electors of Hesse-Kassel until 1866, and later the Prussian kings and German emperors as a summer residence.
UNESCO World Heritage
UNESCO's World Heritage programme is based on the central principle that »parts of the cultural or natural heritage are of outstanding interest and therefore need to be preserved.« To qualify, the heritage must meet three basic requirements: exceptional cultural and/or natural significance, historical authenticity, and integrity. Together, they are referred to as a property's Outstanding Universal Value (OUV). Bergpark Wilhelmshöhe fulfills these criteria due to:
Water Features

Over a distance of about two kilometres and encompassing five principal features all designed to work as monumental »stage sets«, a breathtaking water theatre unfolds. Down the stone staircases and artificial rock formations of the Grand Cascade, via Steinhöfer Waterfall, the Devil's Bridge waterfalls and the Aqueduct with the Peneus Cascades at its foot, the water finally arrives at the Fountain Pond where it rises, driven solely by its own power, in the 50-m Great Fountain – the spectacle's crowning glory.

Their vision of creating a monumental water structure on a hill set the princes of Kassel apart from their peers and contemporaries. Other Baroque rulers displayed their claims to power in the shape of sprawling parks laid out on level ground. At Kassel, Landgrave Carl seemingly conquered nature by releasing vast amounts of water from the top of a hill and channeling them in artful ways. To this day, some 750,000 litres of water are collected for the purpose in various basins, and conducted across Habichtswald by way of subterranean pipelines.

The water features of Kassel were not built under a single patron. Landgrave Carl commissioned the first structures at the end of the 17th century. From 1701 onwards, his Italian architect, Giovanni Francesco Guerniero, built large parts of the ensemble envisioned by the Landgrave. About 130 years later, the water features were completed by Carl's great-grandson, Elector Wilhelm II, who built the New Waterfall. What had been created was a gesamtkunstwerk, a total work of art incorporating various trends in landscape gardening, art history and the history of technology in a manner that can still be experienced today. Large parts of the layout have been preserved in their original substance to the present day.
Technical Innovations

The ruler's determination to conquer a force of nature, the element of water, was a major factor in the technological breakthroughs developed at Kassel. Thus the Landgrave invited the engineer, Denis Papin, to his court and tasked him with developing a machine capable of lifting large amounts of water. Papin devised a steam-powered pump, only to discover that no pipes constructed in those years could withstand the pressure created.

Even though the machine was never put to use at Kassel, it was a direct precursor of the steam engine that was to revolutionise the world soon after. Technological research conducted at the court of the princes of Kassel to further their water-engineering projects has had an impact on the history of technology. The need for pressure-resistant pipes led to trailblazing innovations in the Landgraviate's foundries: 300 years later, some of the original pipelines are still in use today, in contrast to every other garden of that time.
Herkules Monument

Mounting the 11.30 m statue of Hercules in the most difficult of locations - on top of a steep pyramid surmounting an artificial grotto that had been constructed on top of Karlsberg hill - stood as the crowning glory of Landgrave Carl's determined efforts to prove that he would dare the impossible and defy the powers of nature.
The sculpture was created in the years 1713–17, wrought in copper repoussé by the Augsburg goldsmith Johann Jakob Anthoni and mounted on a wrought-iron armature. It is a replica of the Ancient Roman statue of the »Farnese Hercules«, which Landgrave Carl had seen at Rome during his tour of Italy, undertaken in 1700.

It depicts Hercules resting from his labours and contemplating his twelve deeds. Towering above the countryside, the monumental statue was devised to embody both the virtues of a just and wise ruler and the omnipotence of Landgrave Carl. The axis marked by the Grand Cascade and stairs creates a close connection between the monument and the palace further downhill, the demigod and the Landgrave of Hesse, fully in keeping with the Absolutist notion of power and rulership.
Technologically unique, the Kassel statue of Hercules is an early precursor of the copper-wrought colossal statues of the Industrial Age such as New York's Statue of Liberty or the Hermann Monument in Teutoburg Forest. At the time of its creation the sculpture on Karlsberg hill, gigantic and superhuman in the eyes of contemporary viewers, was the most sophisticated large-scale copper-wrought sculpture in the world.