A unique architectural curiosity found only in the Italian city of Florence are tiny decorated openings on the outside walls of many sumptuous palaces. They are about the size of a cat door, but are located below the level of the waist. The openings are blocked by a wooden or iron door, and many doors have knockers.
For many centuries, a surreptitious trade of wine was conducted through these tiny windows. A customer looking to buy wine would knock on the door, whereupon the cellarman or porter appointed by the owner of the house would open the door from the inside. The customer would slip a few coins into the hands of the cellarman, and in return, he would hand the customer a flask of wine.
