Inside the building complex of the Salita del Grillo, near Mercati di Traiano in Rome, there is a rectangular structure with an apse on the wall in the background. The analysis of the remains has established that it is a monumental nymphaeum dated to the Middle Republican age supplied by a branch of the acqua Marcia aqueduct (144 B.C.). This is the oldest public nymphaeum found in Rome and the typology and construction techniques of the monument are similar to contemporary nymphaeums found in the Lazio region, in Italy. The position of the nymphaeum allows to establish the path of the
acqua Marcia towards the Capitol Hill and provides important elements for the area's topography reconstruction.