Fontana dell'Acqua Acetosa

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.

Source: Wikipedia