The back of this postcard reads "Chicago's most famous hot dog." Postcard published by Sunburst Souvenirs, Evanston, IL. The Chicago-style hot dog is a perfect example of how many different ethnic and historical influences can come together to create something uniquely Chicago. The Chicago-style hot dog consists of an all-beef wiener on a steamed poppy-seed bun topped with what is known as the “Magnificent Seven”: mustard, relish, chopped onions, two tomato wedges, a pickle spear, two sport peppers, and a sprinkling of celery salt. The frankfurter aficionados behind the Hot Dog Chicago Style website ( www.hotdogchicagostyle.com ) state that adding these toppings in the order listed here is crucial to ensuring that you can taste all the ingredients in every bite. The Chicago dog was not invented by a single person but rather evolved during the 1920s through the 1950s, according to Bruce Kraig, author of Hot Dog: A Global History (as told to WBEZ in 2017).