Chicago is known for its all-beef hot dogs served with mustard, relish, celery salt, chopped onions, tomato slices, pickled peppers, and dill pickle spears, in a poppy seed bun. And while plenty of vendors sell them, Portillo’s is the place to go. The chain has been running since 1963 in Illinois and over the years it's expanded into other states including Michigan, California, Indiana, Arizona, and Florida.