The Gallo-Roman sanctuary of Vaux-de-la-Celle in Genainville is an important archaeological site discovered in the 1930s by members of the Société Historique de Pontoise.
Excavated since the twentieth century by amateurs and professionals, it is full of testimonies of the Roman occupation of the territory of the Vesliocasses, including the presence of a temple with double cella (rooms) honoring a Roman god (Mercury) and a Celtic goddess (Rosmerta) and a gigantic theatre with an estimated capacity of between 6,000 and 8,000 seats.
The current excavations are carried out by the students of the Valdoisian Student Association of Archaeology, based on the University of Cergy-Pontoise. They also facilitate visits and cultural mediation for visitors.