The Fontana dell'Acqua Acetosa is a fountain in Rome, located in the flat area with the same name, in the quarter Parioli; at this point the river Tiber forms a deep bend before heading north again. The fountain rises at a lower elevation than the street level, and is therefore accessed via a staircase.
In 2003 the Fondo Ambiente Italiano, on the basis of a popular survey, identified it as the monument to which Italians are fondest of.
Wikipedia https://en.wikipedia.org/wiki/Fontana_dell'Acqua_Acetosa_(Rome)
Address 4 Via Enrico Elia, Roma 00197, Italy
Coordinates 41°55'53.476" N 12°29'8.344" E