There are not many nations that can say their national dish has become an international phenomenon. Italy has two such dishes, pasta and, of course, pizza. Both are famous all over the world, both have made the history of Italian food.
In America pizza usually falls into two categories: thick and cheesy Chicago style or thin and more traditional New York pizza. In Italy pizza also falls into two distinct categories: Italian pizza and the rest of the world. It might seem silly considering the basic ingredients, but one taste of a true Italian pizza and that's it. You will never feel the same about this simple and delicious food again.
Pizza in its most basic form as a seasoned flatbread has a long history in the Mediterranean. Several cultures including the Greeks and Phoenicians ate a flatbread made from flour and water. The dough would be cooked by placing on a hot stone and then seasoned with herbs. The Greeks called this early pizza plankuntos and it was basically used as an edible plate when eating stews or thick broth. It was not yet what we would call pizza today but it was very much like modern focaccia. These early pizzas were eaten from Rome to Egypt to Babylon and were praised by the ancient historians Herodotus and Cato the Elder.