One day trip to Florence. What we can not miss?

Under the Medici Chapel is a tiny basement room that Michelangelo hid out in for weeks when the family wanted him killed. It was only discovered many years later and in it, are some of his very well-preserved sketches on the walls. He later used some of the sketches in the Sistine Chapel! Very cool to visit.

Also, visit the perfumery at the Santa Maria NovellaBasilica. It's one of the oldest pharmacies in the world - The nuns have been hand making the soaps and lotions for hundreds of years to raise money for the church. The products are super luxe and there are only a handful of places that you can buy them in the world. It's a nice stop to visit the and a nice surprise for your wife if she likes that sort of thing! 

Greetings!  Ahh, Florence, one of my favorite cities.  I guess I would ask yourself whether you think you will go back to Florence, or not.  If you think you are, I would probably just map out a leisurely walk and stroll through the churches and Piazza's.  If you don't think you will be back, then you would be doing yourself a great disservice by not seeing the Duomo and The Baptistery of St. John.  Though you will need much longer, purchase advance tickets and spend a few hours in the Uffizi Gallery.  I really enjoyed the Bargello National Museum, which is more for sculptures, but has a fantastic David sculpture from Donatello.  Donatello's sculpture is quite different than the more famous one.  I'm not a huge fan of the Gallery of The Academy, but it does house Michelagelo's David.  I also think Santa Maria Novella and Basilica of Santa Croce are well worth seeing.  If I had to narrow it down to one day, I would get to the Uffizi right at opening and spend a few hours, then stroll a little bit around the Arno River and Ponte Vecchio.  Find a nice low key place to have lunch.  In the afternoon, work a walking map around the Duomo and Baptistry, which are right next to each other, and see how you feel about what you want to see or do.  Could be a museum, a church or two, or maybe a stroll through Boboli Gardens.  Or, just sit and people watch in a Piazza with a bottle of great Tuscan wine, Brunello di Montalcino being my recommendation.  Enjoy!