The truth is that when you are down, you feel that this small square is very little for the immense Trevi Fountain. Shocking. One of the most spectacular places in all of Rome from my point of view. A statue that fills you, a beautiful fountain.
A magical moment is to toss the coins. They explain it very well in the article of the Trevi Fountain of Travel Italy :
“The toss of a coin ensures that whoever does it will return to Rome, two that he will fall in love with a beautiful Roman (or Roman) and three that he will marry her (or him) in Rome . What most of the that make this gesture is that the three coins were thrown by three different people in the movie from which it is inspired “