Piazza Trilussa, located directly across from Ponte Sisto, is dedicated to the great Roman satirical poet Carlo Alberto Salustri, better known as Trilussa.
A monument to Trilussa, with a bronze bust by Lorenzo Ferri, was inaugurated in the square in 1950. An inscription features verses from the poem "All'ombra," which perfectly captures the satire and biting irony often directed at corrupt politicians.

Piazza Trilussa, which until 1952 was called Piazza di Ponte Sisto, is home to the beautiful fountain commissioned by Pope Paul V Borghese from architects Jan van Santen (known as Vasanzio) and Giovanni Fontana. It is the final destination of the ancient Trajan Aqueduct, built after the canalization from the Fontana dell'Acqua Paola on the Janiculum was extended to supply the Trastevere and Borgo districts, as well as the Regola and Ponte districts.

The fountain was originally built in 1613 on the opposite bank of the Tiber, near the Mendicanti Hospice. Following the flood of 1870, it was demolished to widen the riverbed and build the walls. In 1898, it was decided to rebuild it on the opposite bank of the Tiber, in its current location in Piazza Trilussa. The task was entrusted to architect Angelo Vescovali: the reconstruction, faithful to the original architecture, was built on the same axis as the bridge and in a position elevated above street level, at the top of a wide flight of fifteen steps.

The fountain, conceived as a monumental arch, features a central niche flanked by two marble Ionic columns. Above, the attic bears an inscription commemorating the work undertaken by Paul V: "S.P.Q.R. (here understood as 'the Municipality of Rome'), needing to widen the opposite bank of the river, had the Acqua Paola fountain moved here from the beginning of Via Giulia and prepared for new work in 1898." At the highest point is the Borghese family coat of arms, symbolized by an eagle and a dragon.