re:Has anyone ever eaten a piece of pizza in Pisa?
well american/itlalian pizza is really naples style pizza, but in the rest of italy you can get a pizza rustica, i am told, (but it is a special dish for Easter. It is deep dish pie filled with wheat, (whole grain wheat, cooked till its a porriage)vegetable and other savory ingredients.

i am not sure were pizza really come from.. i have heard it come from the italian for a piece of pie -- as an idiom, since pizza really means point..refering to the wedge shape..