The very first design and construction was commitioned in 1453 by Pope Nicholas V in the intersection of three streets which was also a place were the ancient aqueduct supplying the water to Rome laid but most of it was ruined during the goths invasion.The fountain was supposed to be a commemoration of bringing the fresh water and mending the ducts providing the pure water to city again.
It was designed and accomplished by a great architect Leon Battista Alberti .Then in 1629, with a death of the Pope a new head of a church Pope Urban VII asked Gian Lorenzo Bernini to prepare a re- design of a structure as he found it not sufficently dramatic and grandeur, then the project was abandomned with another popes death.
The present barouque (almost as dramatic as rococo) design though , as we know it today, is a work of Nicola Savi that was chosen within the competition organized in 1730 by Pope Clement XII .
Finally the fountain was completed in 1762 by Giuseppe Pannini .The fountain was constructed on the back elevation of the Palazzo Poli.
The elevation was decorated with a giant order of Corinthian pilasters with nishes in the exedras and a triumphal arc and a statue of Oceanus in a tritons drawn shell chariot that try to tame the waters and see- horses ( hippocamps)
The fountain was a background in a famous Federico Fellini's film , La Dolce Vita and also in Roman
Holiday starring Gregory Peck and Audrey Hepburn.
Once you are there, do not forget to throw a coin into the water- according to a tradition, throwing one, ensures the visitor's come back to Rome, two will lead to a new romance and three coins guarantee a mariage or a divorce.