The name "Bagni di Mario" was established during the nineteenth century when it was mistakenly identified as a Roman spa of the Republican age built at the time of the consul Caio Mario.The Conserva di Valverde is a Renaissance-era water collection system (1564) carried out by Tommaso Laureti, an architect from Palermo, and was built to feed the Fountain of Neptune (plus other 2 other fountains).The building is made up of a main octagonal tank, four blind ducts that go into the hill and three cans of collection connected to each other. Of great beauty is a very high fireplace completely covered with centuries-old limestone encrustations.