Visitors to the US tend to flock to the same handful of big cities: San Francisco, New York, Las Vegas, LA... These behemoths do have the culture, nightlife and general air of excitement to justify their popularity, but most travellers will be looking to escape the crowds right now, and the US has many more cities to discover. Here we reveal some of America's most underrated yet utterly brilliant cities. Just remember to check state travel advisories before you go.