In 1947, writer John Gunther named Knoxville, Tennessee, the “ugliest city” he visited during his 13-month-long transcontinental survey of the United States. Spurred by the insult (which was made famous in Gunther’s best-selling guide, Inside U.S.A.), Knoxville officials began a city-wide beautification process to turn things around. New parks, renovated buildings, and striking architecture quickly became the norm in the Tennessee town.Thankfully for Knoxville, the transformation worked, and Travel + Leisure readers think it’s now one of the country’s most architecturally compelling cities. Other destinations they love for architecture include several colonial cities that have preserved their historic cores, former industrial hubs that built monumental public buildings during boom years in the early 20th century, and a city with a skyline defined largely by miniature recreations of the world’s most famous landmarks.In the annual America's Favorite Places survey, readers of all stripes evaluate hundreds of cities and towns across a range of categories, from the friendliness of the locals to the quality of the pizza. Unlike Travel + Leisure's World's Best Awards , which encourages readers to weigh in on travel experiences across the globe, the America's Favorite Places survey is a way for locals to share what their hometowns do best.And when it comes to attractive facades and iconic silhouettes, some cities are more memorable and instantly recognizable than others. From the Rust Belt to upstate New York, these are America’s favorite cities for architecture.Travel + Leisure’s America’s Favorite Places survey opened on 10/8/2015 and closed on 04/15/2016. It was open to everyone, and ran alongside a sweepstakes. The open-response survey asked respondents to submit their favorite place and rate it in over 65 categories, including affordability, notable restaurants, and public parks. Cities are defined as governed bodies with a population over 100,000.