We have discovered the key to keeping teenage girls happy on a hot, humid, day in Florence, Italy: alternate between air-conditioned museums with good audio tours, a little street vendor shopping, and gelato (we recommend twice a day).
Today we spent the day seeing the sights around Florence. Our morning started with a trip to the Academia to see the statue of David and other works of art by Michelangelo; followed by viewing the amazing collection of art at the Uffizi Gallery, a stroll across the Ponte Vecchio, and a stop by the Straw market to rub the nose of the boar. If you rub it you have good luck to bring you back to Florence (it worked the last time Karen and I were here.) For the museums we highly recommend the Firenze card. It allows you to enter the museums through the reserved line, no matter the time you are there, which greatly reduces your waiting time outside the museums.
We then ended our day with a fantastic, true Italian dinner (no pizza for Kelsey) at La Giostra.
Hammond Adventures 
Kelsey’s plate at the Italian restaurant looked very clean or did she just not ever have anything on it since there was no pizza. We recognized things in your pictures so are having fun thinking back to our trip. Stay cool.