As a reference to the volatility of the sea, one of the seahorses is passive, while the other is wild. Other statues surround the fountain as well, each representing different facets of the natural world. The one exception is a figure of Agrippa, the person in charge of building the aqueduct in 19 B.C. Tradition states that visitors who want to return to Rome in the future should turn their back and toss a coin into the fountain.