The flamboyant baroque ensemble was designed by Nicola Salvi in 1732 and depicts Neptune's chariot being led by Tritons with sea horses – one wild, one docile – representing the moods of the sea. The water comes from the aqua virgo , a 1st-century-BC underground aqueduct, and the name Trevi refers to the tre vie (three roads) that converge at the fountain. It's traditional to throw a coin into the fountain to ensure your return to the Eternal City. It's usually very busy around the fountain during the day, so it's worth trying to visit later in the evening when you can appreciate its foaming majesty without the hordes.