Animatronio mentioned a fountain. That's a statue of Neptune, god of water. The number of points on him trident is three, or trey. The "u" in his name is written like "v". Trey, "v". Trevi! It's the Trevi Fountain. There can be no question!

I watched all of Futurama, but I don't remember that episode. Which one was it?

This reminds me of national treasure so much. Literally just random jumps until you fall into the obvious answer.