The Trevi fountain is at the ending part of the Aqua Virgo,
an aqueduct constructed in 19 BC. It brings water all
the way from the Salone Springs (approx 20km from Rome)
and supplies the fountains in the historic center of
Rome with water.
In 1732, Pope Clement XII commissioned Nicola Salvi to
create a large fountain at the Trevi Square. A previous
undertaking to build the fountain after a design by
Bernini was halted a century earlier after the death
of Pope Urban VIII. Salvi based his theatrical

masterpiece on this design. Construction of the monumental baroque
fountain was finally completed in 1762.
The central figure of the fountain, in front of a large
niche, is Neptune, god of the sea. He is riding a chariot
in the shape of a shell, pulled by two sea horses. Each
sea horse is guided by a Triton. One of the horses is
calm and obedient, the other one restive. They symbolize
the fluctuating moods of the sea.
On
the left hand side of Neptune is a statue representing
Abundance, the statue on the right represents Salubrity.
Above the sculptures
are bas-reliefs, one of them shows Agrippa, the girl
after

whom the aqueduct was named.
The water at the bottom of the fountain represents the sea.
Legend has it you will return to Rome if you throw a
coin into the water. You should toss it over your shoulder
with your back to the fountain.