The Fountain of Four Rivers depicts the allegories for the four great rivers in the four continents recognized by the Renaissance geographers. These are the Nile in Africa, Ganges in Asia, the Danube in, Europe, and the Rio de la Plata in America. Each has animals and plants that further carry forth the identification, and each carries a certain number of allegories and metaphors with it. The Ganges carries a long oar, representing the river's navigability. The Nile's head is draped with a loose piece of cloth, meaning that no one at that time knew exactly where the Nile's source was. The Danube touches the Papal coat of arms as it is closest to Rome. And the Río de la Plata is sitting on a pile of coins, a symbol of the riches America could offer to Europe. Also, the Río de la Plata looks scared by a snake. It shows the rich men's fear that their money could be stolen. Each is a river god, semi-prostrate, in awe of the central tower, epitomized by the slender Egyptian obelisk symbolizing by Papal power surmounted by the Pamphilj symbol which is the dove.

In addition, the fountain is a spectacle of action that can be strolled around, a theater in the round. From the Water fountain, the water flows and splashes from a jagged and pierced mountainous disorder of travertine marble. According to the legend common among tour guides, Bernini positioned the cowering Rio de la Plata River as if the sculpture feared the facade of the church of Sant'Agnese by his rival Borromini could crumble against him. But in actuality, the fountain was completed several years before Borromini began work on the church.

The Fountain of Four Rivers was also plagued with controversies because the making of the fountain was met by opposition by the people of Rome for several reasons. First, it is said that Innocent X had the fountain built at public expense during the intense famine of 1646-48. Murmur and talk of riot was in the air throughout the construction of the fountain the city. Pasquinade writers protested the construction of the fountain in September 1648 by attaching hand-written invectives on the stone blocks used to make the obelisk. Pasquinade is an often anonymous lampoon or satire that was traditionally displayed in a public place. The pasquinades condemned the construction of the obelisks and fountains and reiterating that what they want is bread and bread alone. Innocent quickly had the authors arrested and disguised spies patrol the Pasquino statue and Piazza Navona. Not contented to sending pasquinade authors, he also expelled the street vendors who opposed the construction of the fountain from the piazza. The Pamphilij pope believed they detracted from the magnificence of the square. In retaliation, the vendors refused to move and the papal police had to chase them from the piazza.