The endless stream of memes; the crossover into high couture; the ability to order delivery with emojis; the dedicated slice harvesters who document every minute detail on their blogs—all the advancements, scholarship, and tributes paint a pretty clear picture that America is, and will always be, obsessed with pizza.

Along with thousands of Italian immigrants, pizza arrived in America in the late 1800s, but our favorite food went virtually unnoticed until the 1950s. Many believe it was soldiers returning from World War II with a craving for Italian food that spurred the initial craze, while others point to improvements in oven technology and user-friendly grocery-store pizza kits. Some even insist it was the promotion of Italian food by popular celebrities such as Frank Sinatra, Sophia Loren, and Dean Martin (remember “That’s Amore”?) that encouraged Average Joes to jump on the bandwagon.

However it took off, the stats indicate that pizza is here for the long haul. There are approximately 75,000 pizzerias in the United States, with nearly $40 billion spent on the humble combination of flour, water, salt and yeast. Out of that simple formula, however, grew a spectrum of pizza styles, with each region of the country leaving its own unique imprint through differing methods, ingredients, and resources available. In that sense, pizza is a valuable indicator of a person's roots. Whether it’s the style they lean toward (thick versus thin) or the toppings they pile on (light versus heavy; traditional versus gourmet), you can often determine what part of the country people hail from—and sometimes even their age.

So what does it mean, then, if someone craves Old Forge pies? What region are you from if you grew up eating dough spiked with a heavy dose of brewer's malt? Is D.C. really home to the largest slices? To make sense of it all, we present to you a taxonomy of pizza styles here in America.