The world is in an unprecedented period of tourism growth, and not everyone is happy about it. Arrivals by international tourists have nearly doubled since 2000, with 674 million crossing borders for leisure back then and 1.2 billion doing the same in 2016.

As the travel industry has ramped up its operations around the world, destinations have not been well-equipped to deal with the economic, social, and cultural ramifications. Cities have often made economic growth spurred by traveler spending a priority at the expense of quality of life for locals.

Europe has been perhaps hardest hit by the stress of increased travel and tourism. Barcelona, Venice, and Reykjavik are just some of the cities that have recently been transformed by visitors.

For the last few months, news reports have reflected the truth about the global travel industry: Not enough has been done to limit the negative impact of tourism as it has reached record levels in destinations around the world. Anti-traveler sentiment is seemingly on the rise.

“I would consider [these cities] to be canaries in the coal mine,” said Megan Epler Wood, director of the International Sustainable Tourism Initiative at the Center for Health and the Global Environment at the Harvard School of Public Health. “The folks that have been protesting are from highly visited destinations and they don’t feel their lives should be interrupted by tourism.”

She continued: “They’re in a position of making a statement… something I’ve been discouraged about is the idea that people who are protesting are making a mistake. It’s important they make a statement because we need to hear from them and come to a new level of understanding of what this means. We need to very seriously find what their concerns are and figure out how to plan with those destinations and think about acting proactively.”

Why have some destinations thrown up their hands in helplessness in dealing with the deluge of tourists? And what have other destinations done to successfully limit the effects of increased visitation?

Skift has identified five solutions to overtourism, drawing from what destinations have done successfully to limit the influx of tourists, and we spoke to global tourism experts about their perspectives. We also looked at the ways in which travel companies themselves have been complicit and what more they can do to grow global tourism in a more sustainable way. We don’t argue that these are one-size-fits-all solutions for every trampled-upon destination, but they may serve as a solid foundation for beginning to tackle the problem.

Furthermore, we look to the future for ways in which the travel industry, in conjunction with local stakeholders, can better measure and limit the adverse effects of tourism.

If the travel industry can help connect the world and build bridges between cultures, why has it struggled to find a sustainable path forward?