National Detroit-Style Pizza Day is observed worldwide every June 23 to celebrate the unique square-cut pan pizza known as Detroit-style pizza. This style features a thick, crisp crust topped with Wisconsin brick cheese and tomato sauce, with other toppings added on top of the cheese. The holiday originated in 2011 when the then-mayor of Detroit, Dave Bing, declared June 23 as "Buddy’s Pizza Day" to mark the 65th anniversary of this iconic dish, which was developed at Buddy’s Pizza, a pizzeria opened in 1936. In 2021, the name was changed to National Detroit-Style Pizza Day to commemorate its 75th anniversary. To celebrate, people are encouraged to enjoy authentic Detroit-style pizza at Buddy’s Pizza locations or other pizzerias, or to make their own version at home. Sharing photos of the pizza on social media with specific hashtags is also a common practice among enthusiasts.