It is located on the Paseo del Prado, near the Fuente de Cibeles, to which it is a sister fountain. It represents the Roman god of the sea with his trident in his chariot pulled by horses with fish tails that seem to come out of the water.
The fountain was commissioned by King Charles III from the architect Ventura Rodríguez, who created the fountain of Cibeles at the same time. Made of white marble, the monument represents the god Neptune (Poseidon for the Greeks), god of the seas in Roman mythology, on a chariot pulled by two sea horses with fish tails.
Address: Plaza de Cánovas del Castillo