This fountain means to depict allegories for the four great rivers in the four continents recognized by the Renaissance geographers: the Nile in Africa, Ganges in Asia, Danube in Europe, and Río de la Plata in America. Each has animals, plants, or river gods with sometimes awkward racial physiques to carry forth the identification. Each has a river god, semi-prostrate, in awe of the central tower, epitomized by the slender Egyptian obelisk (built for the Roman Serapeum in AD 81), symbolizing by Papal power surmounted by the Pamphilij symbol (dove). In addition, the fountain is a theater in the round, a spectacle of action, that can be strolled around. Water flows and splashes from a jagged and pierced mountainous disorder of travertine marble. A legend, common with tour-guides, is that Bernini positioned the cowering Nile River as if the sculpture was fearing the facade by his rival Borromini could crumble against him. history lesson over now to photo ....brilliant