Palazzo Poli is another magnificent landmark of the Trevi Square. This palace, owned by the Duke of Poli, along with the Trevi Fountain, forms a unified architectural ensemble in the Baroque style. The duke was a relative of Pope Urban VIII, under whose initiative the fountain's construction began. Palazzo Poli was built in the 16th century, before the fountain appeared, so it had to be significantly rebuilt. In 1730, the central part of the palace was demolished to make way for the fountain.

In the 1830s, the Russian poetess and singer Princess Zinaida Volkonskaya settled in Palazzo Poli. Her literary and musical salon hosted such celebrities as Stendhal, Vasily Zhukovsky, Walter Scott, and Fyodor Tyutchev. Here, Nikolai Gogol read "The Government Inspector" to the public.

The facade of Palazzo Poli was created by architect Luigi Vanvitelli, while Nicola Salvi and Pietro Bracci worked on the exterior decoration. The ensemble of the palace and fountain is a unique masterpiece of Baroque. At the center of the composition is Neptune, emerging from the central entrance of the palace in a chariot shaped like a seashell, drawn by sea horses. In the niches on either side of the facade are sculptures of the goddesses of healing and abundance, created by Filippo Valle. The building also features reliefs by Giovanni Grossi: on the left is the virgin Agrippina, examining the aqueduct, and on the right, a virgin pointing the legionnaires to the source.

Zinaida Volkonskaya (1792, 1862) was known in Russia as the hostess of magnificent salons in St. Petersburg and Moscow. She was celebrated in poems by Pushkin, Mickiewicz, Baratynsky, and Vyazemsky. The princess engaged in painting, wrote novellas, and organized amateur opera performances and musical evenings in Paris, Rome, St. Petersburg, and Moscow.

In the spring of 1829, Volkonskaya left Russia and settled in Rome. This was due to several reasons: she decided to convert to Catholicism, which was not welcomed at court, and her brother-in-law, Nikita Volkonsky, participated in the Decembrist uprising. The princess even held a farewell reception for the wives of the Decembrists going to Siberia, for which she came under police surveillance.

She lived in Rome until the age of 69 and was known not only for her social talents but also for her piety. According to legend, she died of a cold after giving her cloak to a freezing beggar.

In Italy, they remember the Russian princess, whom the Roman poor called the Pious, and even named one of the streets of the Eternal City in her honor.