The Fountain of Piazza Colonna, as the name indicates, can be found on the Piazza Colonna, just off the Via del Corso, in the historical center of Rome.
Piazza Colonna Fountain Rome
History and description

The Piazza Colonna Fountain was commissioned by Pope Gregory XIII Boncompagni, designed by Giacomo della Porta and sculpted by Rocco de Rossi.
The Fontana di Piazza Colonna was finished in 1577, but the two groups of dolphins were sculpted by Alessandro Stocchi and added during a restoration in 1832, when it was also made smaller than in its original version.
The fountain gets its water from the Acqua Vergine Aqueduct.