What US city is famous for a type of no-cheese pizza called "tomato pie"?

Philadelphia's traditional no-cheese pizza has roots in the southern Italian island of Sicily. There, Sicilians topped their pies with tomatoes, anchovies, onions, and oregano — but rarely, if ever, cheese. That's largely due to the lack of dairy cows in southern Italy.

In the early 1900s, Italians immigrated to Philadelphia, bringing that southern Italian no-cheese pie along with them. Like many foods from other countries, the pie was soon Americanized, onions and anchovies became a topping of the past, and it earned the official name, "tomato pie."

Today, Philadelphia has two main tomato pie types: Philly bakery style and Trenton style. The bakery-style pie has a focaccia-like dough with chunky tomato sauce and few if any, cheese toppings. The Trenton-style pie from neighboring New Jersey is like a traditional thin-crust pizza, except reversed: The cheese is on the bottom, and it's topped with crushed tomato.