A Neapolitan baker named Gennaro Lombardi opened the nation’s first pizzeria in New York in 1905, and to this day Lombardi’s pies stand up as stellar examples of Italian-America’s take on the Neapolitan original: Larger in size, they’re topped with fresh-tasting sauce, milky mozzarella, grated Romano cheese, olive oil, and aromatic basil leaves, and cooked in a coal oven. Today, most New York pizza uses coarser flour, gooier industrial mozzarella, and a longer cook-time in an electric oven.

In New Haven, Connecticut, a different style of pizza, known as apizza, evolved from the same Neapolitan roots. Frank Pepe opened his eponymous pizzeria in that city’s Little Italy in 1925, and today his establishment and neighboring ones still make pies that are thinner, wetter, and more heavily charred than most New York-style pizza. In the mid 1960s, Pepe introduced its signature clam pizza topped with juicy bivalves, grated pecorino, garlic, and oregano.

Chicago pizza is a different beast entirely. When Pizzeria Uno founders Ike Sewell and Ric Riccardo invented it in 1943, they weren’t trying for true Italian. They believed Chicagoans needed something more substantial, ergo deep dish pizza, which is more a casserole than a flatbread.

California is where pizza became boutique food, starting in the 1980s, as part of a larger exaltation of Mediterranean cuisine. Alice Waters put a wood-burning oven into Berkeley’s the Cafe at Chez Panisse, and Wolfgang Puck got famous by feeding Hollywood stars $100 caviar pies. Puck’s pizza man, Ed LaDou, went on to found the California Pizza Kitchen chain, now famous around the country for its barbecued-chicken pizza.