The fountain in the Piazza Colonna is a fountain in Rome, Italy, designed by the architect Giacomo Della Porta and constructed by the Fiesole sculptor Rocco Rossi between 1575 and 1577.
The fountain was one of a group of sixteen fountains built by Della Porta following the reconstruction of the Acqua Vergine aqueduct, a project begun by Pope Pius IV in 1561 and finished by Pope Pius V in 1570. The fountain itself was built under Pope Gregory XIII, best known for creating the Gregorian calendar. Like the other Roman fountains of its time, it was built to provide clean drinking water to the Roman residents, who before then had to drink the polluted water of the Tiber River. Also like the other fountains of its time, it operated purely by gravity; the source of the water was higher than the fountain itself, causing the water to spout into the air.
The water for the fountain first arrived at the old Trevi Fountain, then went to two reservoirs at the foot of the butte of San Sebastiancello, then through a series of the channels to the corner of via Condotti and the via del Corso, to Piazza Venezia, to the foot of the column of Marcus Aurelius.