MADRID — Suitcases rattle against cobblestones. Selfie-snappers jostle for the same shot. Ice cream shops are everywhere. Europe has been called the world’s museum, but its record numbers of visitors have also made it ground zero for concerns about overtourism.

Last year, 747 million international travelers visited the continent, far outnumbering any other region in the world, according to the U.N.’s World Tourism Barometer. Southern and Western Europe welcomed more than 70% of them.

As the growing tide of travelers strains housing, water and the most Instagrammable hotspots in the region, protests and measures to lessen the effects of overtourism have proliferated.

What’s causing overtourism: Among factors driving the record numbers are cheap flights, social media, the ease of travel planning using artificial intelligence and what U.N. tourism officials call a strong economic outlook for many rich countries that send tourists despite some geopolitical and economic tensions.

Citizens of countries like the U.S., Japan, China and the U.K. generate the most international trips, especially to popular destinations, such as Barcelona in Spain and Venice in Italy. They swarm these places seasonally, creating uneven demand for housing and resources such as water.

Despite popular backlash against the crowds, some tourism officials believe they can be managed with the right infrastructure in place.

Where overtourism is most intense: Countries on the Mediterranean are at the forefront. Olympics-host France, the biggest international destination, last year received 100 million international visitors, while second-place Spain received almost 94 million — nearly double its own population.

The impact of overtourism: In Spain, anti-tourism activists, academics, and the government say that overtourism is driving up housing costs in city centers and other popular locations due to the proliferation of short-term rentals that cater to visitors.

Others bemoan changes to the very character of city neighborhoods that drew tourists in the first place.

In Barcelona and elsewhere, activists and academics have said that neighborhoods popular with tourists have seen local shops replaced with souvenir vendors, international chains and trendy eateries.

On some of Greece’s most-visited islands, tourism has overlapped with water scarcity as drought grips the Mediterranean country of 10.4 million.

In France, the Louvre, the world’s most-visited museum, shut down this week when its staff went on strike warning that the facility was crumbling beneath the weight of overtourism, stranding thousands of ticketed visitors lined up under the baking sun.

Angelos Varvarousis, a Barcelona- and Athens-based academic and urban planner who studies the industry, said overtourism risks imposing a “monoculture” on many of Europe’s hotspots.

“It is combined with the gradual loss and displacement of other social and economic activities,” Varvarousis said.