Strasbourg features a number of prominent parks, of which several are of cultural and historical interest: the Parc de l'Orangerie, laid out as a French garden by André le Nôtre and remodeled as an English garden on behalf of Joséphine de Beauharnais, now displaying noteworthy French gardens, a neo-classical castle and a small zoo; the Parc de la Citadelle, built around impressive remains of the 17th-century fortress erected close to the Rhine by Vauban; the Parc de Pourtalès, laid out in English style around a baroque castle (heavily restored in the 19th century) that now houses a small three-star hotel, and featuring an open-air museum of international contemporary sculpture. The Jardin botanique de l'Université de Strasbourg (botanical garden) was created under the German administration next to the Observatory of Strasbourg, built in 1881, and still owns some greenhouses of those times. The Parc des Contades, although the oldest park of the city, was completely remodeled after World War II. The futuristic Parc des Poteries is an example of European park-conception in the late 1990s. The Jardin des deux Rives, spread over Strasbourg and Kehl on both sides of the Rhine opened in 2004 and is the most extended (60-hectare) park of the agglomeration. The most recent park is Parc du Heyritz (8,7 ha), opened in 2014 along a canal facing the hôpital civil.