European Heritage Days in Essonne

European Heritage Days in Essonne: two days to explore an exceptional department

Every third weekend in September, the European Heritage Days (JEP) transform Essonne into a vast open-air museum. Dozens of sites, many of which are closed to the public the rest of the year, exceptionally open their doors to allow everyone to discover the richness of Essonne's heritage.

A department with exceptional heritage

Essonne is an often little-known department but holds remarkable heritage treasures:

• 76 monuments classified as Historical Monuments
• 193 buildings listed in the Supplementary Inventory of Historical Monuments
• 21 gardens protected as Historical Monuments
• Medieval, Renaissance, and Classical castles (Dourdan, Chamarande, Méréville, Vaux-le-Vicomte on the border)
• World-class scientific institutions: Université Paris-Saclay, École Polytechnique, Essonne Tourisme

Iconic sites open during the JEP

Among the sites that open their doors during the Heritage Days in Essonne:

• Château de Dourdan: 13th-century medieval fortress with themed evenings
• École Polytechnique in Palaiseau: guided tours of laboratories and architectural heritage
• Pagode Khánh-Anh in Évry-Courcouronnes: the largest pagoda in Europe
• Château de Villiers in Draveil: visits of this listed monument
• Musée des Sciences ACO in Orsay: the Orsay Collision Ring, a pioneer of world physics
• Mus'X – Musée de l'École Polytechnique: historical scientific instruments, uniforms, and archives
• Le Cyclop in Milly-la-Forêt: monumental sculpture by Jean Tinguely and Nikki de Saint Phalle
• Domaine de Méréville: remarkable 18th-century landscaped garden

A unifying theme each year

Each edition of the Heritage Days is placed under a national theme that guides the proposals of the participating sites. In 2025, the theme was architectural heritage. These themes allow sites to renew their programming and open new perspectives on their history.

Guided tours and educational activities

Beyond simple visits, the JEP in Essonne offer:

• Guided tours led by passionate volunteers, conference guides, and property representatives
• Educational workshops for children and families
• Temporary exhibitions on the history of the sites and the department
• Shows and performances in exceptional heritage settings
• Concerts in chapels, castles, and historic gardens

Essonne, department of science and culture

Essonne is home to the Saclay plateau, the scientific heart of Île-de-France with its grandes écoles and research laboratories. This scientific and industrial heritage, often unknown to the general public, is highlighted during the JEP, just like the castles and gardens.