Think you know pizza? These regional varieties may make you reconsider crowning yourself a connoisseur of this Italian-American cuisine. Even those who believe (as we do) that pizza deserves to be it’s own food group may not recognize St. Louis pizza, sfincione, or Trenton tomato pies—or, may not fully understand the unique nuances that go into each pizza variety. Click through for the full low-down on everyone’s favorite cheesy treat.