Every summer, millions of people jet off on vacations around the world. The United Nations World Tourism Organization estimates that international arrivals, the measure of global travel, will be 2% higher than the pre-pandemic total was in 2019. However, as more of us are taking vacations, some of the world's tourism hotspots are feeling more crowded than ever. And that's even led to protests in some popular destinations. Residents in some European cities have marched through popular areas, calling on tourists to "go home." Some destinations, like Amsterdam, are doing what was previously thought unthinkable and actively discouraging visitors. Tourism crowding has become an indelible feature of travel and it warrants some understanding. So, what is overcrowding in tourism? How do we respond to it? And why does it appear to be increasing? ....