Wikimedia The best-known secret in Florence is known of by many, but visited by almost none, and its story runs through the heart of Florentine history, literally and figuratively. Every tourist in Florence will see it, because everyone visits the Ponte Vecchio, and the corridor passes just above it. But few are aware of what they are seeing, inauspicious as it appears from the outside. The passage is around a kilometer long and runs from the Palazzo Vecchio, the headquarters of the Medici rulers of Florence, to the Palazzo Pitti, a newer residential palace built on the far side of the Arno River.