Pizza arrived in the U.S. during a wave of southern Italian immigration in the early 20th century. It's difficult to imagine that one of America's most beloved foods has only been sold here since 1905, per Serious Eats. The first pie, served out of a grocery store in New York City, was based on a Neapolitan style. However, Gennao Lombardi adapted that seminal pie with local ingredients and preparations.

And in such a manner, regional Italian pizza variations mixed and mingled with outside influences. Now, there's everything from Roman, and Cajun, to Sicilian Pizza found in New York City, reports Eater. Sicilian pizza, also known as Sfincione, was born from market vendors and bakers, and popularized in cities like Palermo. Noted for its square shape, it's defined by a unique dough and taste explains Best of Sicily Magazine.