that this thread has been up for 6 hours without anyone mentioning Gary, Indiana.
So, I'll take this occasion to share my original research on the origin of pizza:
All this "Italian / Neapolitan" fiction is cultural appropriation of the most vile sort.
Recent research by Alton Brown and the late Anthony Bourdain has revealed that what we now call "pizza" originated where the Land of Tippecanoe met the Great Waters. It seems that Chief Gahree of the Kickapoo Tribe sought a fitting accompaniment to their legendary "Joy Juice". The tribe was so pleased with the culinary creation they named the location after their Chief. Since, his name became 'Anglicized' to the now familiar "Gary".
After the Kickapoo were vanquished by future President William Henry Harrison at the Battle of Tippecanoe, their traditions did not perish as several surviving members of the tribe made it to NYC via the Erie Canal. Soon after they encamped in SE Manhattan and made a prosperous living by selling their Joy Juice and Chief Gahree's wonderful creation.
All went well for nearly fifty years until their territory was invaded yet again, this time by Sicilians and Neapolitans. Soon, the "newcomers" made the Kickapoo "an offer they couldn't refuse"!
And the rest is the history that involves New York City and Italian immigrants.