Best tourist destination: Cape May, New Jersey Underrated hidden gem: Galena, Illinois Best for outdoor adventure: Girdwood, Alaska Best for history lovers: Taos, New Mexico Best for couples: Palisade, Colorado What makes a small town beautiful? The answer is, naturally, subjective. Perhaps you have a penchant for windswept coasts. Or maybe it's something about a town's unique history and culture—or its proximity to a popular wine or bourbon trail—that draws you in. To offer a glimpse at a variety of gorgeous places around the country, we considered destinations from coast to coast. Here's a look at 20 of the most beautiful small towns in the U.S., all with populations under 20,000. Cape May, New Jersey Joice Brinkerhoff / Getty Images Not only is Cape May one of the most beautiful small towns in the U.S., it's also one of the best Jersey Shore towns to visit , especially in summer.…