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. What park is built close to the Rhine by Vauban?