The rivers represented in the fountain are the Danube, the Ganges, the Nile and the Rio de la Plata. They are arranged on a steep rocky reef from which a Roman obelisk taken from the Cirucus of Maxentius rises up into the air. Rumor has it that sculptures on the fountain symbolize the rivalry between Bernini and Borromini. Innocent the X first commissioned Borromini, but Bernini obtained the comminssion by corrupting Donna Olimpia, the Pope's sister-in-law.

