Florence is located on the banks of the river Arno, between the Adriatic and Tirreno Seas. The city is almost in the middle of the Italian boot (the peninsula, I mean).
It is a city full of life, but over all it is a city full of tourists. In the city center you will find millions of tourists, that come from everywhere in the world. If you plan to visit this fabulous city, reserve ahead, because it is always high season here (yes, this affects prices too).