This Tuscan hill town will transports us back to the Middle Ages. Siena's grand cathedral, built in the 1200s, has treasured artworks and marvellous marble floors. The Piazza del Campo, the main town square, is a UNESCO World Heritage Site. It's also home to the Palio, perhaps the most infamous horserace in the world. No goofy hats and mint juleps here—this is a medieval tradition involving bareback riders racing on cobblestones (so as you might imagine, it's quite dangerous).