In its annual America’s Favorite Cities survey, readers of Travel + Leisure were asked to pick the dirtiest cities in the country. As for what constitutes "dirty," it could be litter, smokers, air pollution, homeless people, graffiti, and even the taste of local tap water.

Before I list the top 13 dirtiest cities, I should mention that I am not surprised that some of the dirtiest were also ranked as some of the hottest destinations. Just because the city is filled with litter does not mean it isn't fun to visit. For example, cities such as Memphis, Las Vegas, and Miami scored high marks for great bars, live music, and people-watching. Great bars usually means smokers who also happen to be people who can't help littering.