Florence is a magical city on the way north. For many tourists it is the stopping point for a day trip to Pisa, while for local Italians Pisa is somewhat of a joke. Florence has a lot to offer for a short trip. Its most famous landmark would be the massive Duomo. Unlike other churches you may see in Italy, it is intricately designed on the outside. Entry is free, but the line can be often long. To the side, one can climb the tower to see Florence from the top.
Accademia Gallery a bit off central Florence has the overly famous statue of David (although a copy lies in the central square). The line is usually one hour long, and other than David the museum may not be too interesting for most travelers.
Another long line waits for you at Galleria degli Uffizi, which is definitely worth the wait. This beautiful museum is enormous and often the long lines keep it from being unbearably crowded. If you enjoy renaissance art, this is the place to go. Try to book a spot in advance, or plan on spend upwards of an hour and a half in a line.
Ponte Vecchio is another Florence landmark. This bridge crosses the Ano and houses several jewelry shops as is tradition. If you look above you will see a connecting walkway that snakes from the bridge connecting both Medici Palaces. Apparently Mussolini had windows cut out for Hitler’s visit. The walkway is inaccesible unless you know the right people.
Across the Ponte Vecchio you will find more welcoming streets and yet another museum/palace. The lines are shorter since few venture so far out, but the other side of Florence is also pretty nice.