I had this bread and tomato soup on my honeymoon (or luna de mare since we were in italy) and learned how to make it from the cookbook of my favorite restaurant while there - Cibreo. If you are going to Florence, visiting cibreo is a must! Its one of those recipes that came from the old world that is

Here is the recipe (sort-of, its kind of a mish-mash!)
Serves 8 (large servings!)

10 tomatos peeled and seeded and pureed
1.5 lbs of stale italian bread
1c. Olive oil
1 hot pepper or ground chili peper (optional)
3-1,000,000 cloves of garlic, chopped or sliced (depends on the quality of the garlic and whether you plan on kissing anyone that evening!)

Lots and Lots of fresh basil

As much (or none) of these as you feel appropriate or have available:
carrots
celery
Red Onions
Leeks

Directions:
1) Fry up the veggies and pepper (optional) until they are golden in a large frying pan or (preferably) some kind of ceramic pot.
2) Drop in the tomatoes and some more olive oil Cook for 15 minutes
3) While the tomato batch is cooking, Soak the bread in water until thoroughly soaked. mix it into a paste
and then drain the water and ring as much out of the bread paste as you can.
4) Drop in the bread and garlic. Add more olive oil, Cook for 10 more minutes
5) Chop up the basil while the batch is cooking
6) Turn off the heat and mix in the chopped basil.
7) Mix in whatever olive oil is left

let sit and serve!