If you live in Chicago, it's a beef frank and you eat it on a poppy seed roll with mustard, relish, onions, pickles, tomatoes and celery salt. If you're in Rochester, N.Y., it's a spicy pork sausage -- split, grilled and nestled in a toasted bun. The varieties are as endless as the stories of its origins. Are they called franks because they were invented in Frankfurt, or are they called wieners because they come from Wien (aka Vienna)? Nobody knows for sure, but one thing's certain: A hot dog's not a hot dog until it's sitting in a bun. And that important innovation is all-American.