The United States may be one country, but sometimes, traveling through it is like hopping from one planet to another—each state is more different than the next. That's why we've consulted our complete guide to etiquette for handy tips to know before you visit some of the top U.S. cities, compiling all the do's, don'ts, and definitely nots you need to be aware of, according to our Traveler editors. For example, did you know putting ketchup on a hot dog in Chicago is practically sacrilegious? Or that in Nashville, the best honky tonk isn't always on Broadway? Keep scrolling to learn more.