The short answer is
both.
While the city did invent the iconic deep-dish, the vast majority of Chicagoans actually prefer
thin crust pizza commonly known as
tavern style pizza. Although some Chicagoans will fight you on the name, the style originates in 1920s taverns, so it's called tavern style.
Tavern style pizza has a long history in Chicago. It features a super thin and cracker-like crust that is crispy and flakey but not hard. It's firm enough to hold a perfect amount of sauce and toppings without flopping over. Then, it's cut into small squares perfect for passing around the bar or table.
This style of pizza traces its origins back to the Great Depression when bar owners needed a way to entice customers to stop by and stay longer. They'd serve up these square cut slices on napkins to thirsty patrons to keep them drinking without filling them up. It's just the right amount of salty goodness to keep you thirsty and hungry for more.
Over the years square cut thin crust pizza has gained popularity and spready around the Midwest. St louis and Ohio both have claims as the original tavern style pizza creators but good luck convincing any Chicagoans of that (myself included).
Fast forward to 2019 and Chicago native Jared Leonard brought this tradition to Denver, with Grabowski’s Pizzeria in Lakewood, CO.
Jared knows his pizza and has absolutely nailed the cracker crust on his tavern style pizza. Grabowski’s also offers a full service bar and even an arcade where you can book
private events. When you're in the neighborhood definitely stop by Grabowski’s for authentic Chicago pizza experience.