Villennes-sur-Seine, a charming commune in the Yvelines department, is home to a little-known treasure: the waterfalls of the Parc Fauvel grotto. Located some 36 kilometers west of Notre-Dame Cathedral in Paris, this small town near Poissy on the left bank of the Seine boasts a park that combines history and nature. The park, an example of English romanticism, features an unusual grotto and waterfalls.